Provided by: fetchmail_6.3.26-3ubuntu1_amd64 bug

NAME

       fetchmail - fetch mail from a POP, IMAP, ETRN, or ODMR-capable server

SYNOPSIS

       fetchmail [option...] [mailserver...]
       fetchmailconf

DESCRIPTION

       fetchmail  is  a  mail-retrieval  and  forwarding  utility;  it  fetches  mail from remote
       mailservers and forwards it to your local (client) machine's  delivery  system.   You  can
       then  handle  the  retrieved mail using normal mail user agents such as mutt(1), elm(1) or
       Mail(1).  The fetchmail utility can be run in a daemon mode to repeatedly poll one or more
       systems at a specified interval.

       The  fetchmail  program  can  gather  mail from servers supporting any of the common mail-
       retrieval protocols: POP2 (legacy, to be removed from  future  release),  POP3,  IMAP2bis,
       IMAP4,  and  IMAP4rev1.   It  can  also  use the ESMTP ETRN extension and ODMR.  (The RFCs
       describing all these protocols are listed at the end of this manual page.)

       While fetchmail is primarily intended to be used over on-demand TCP/IP links (such as SLIP
       or  PPP  connections),  it  may also be useful as a message transfer agent for sites which
       refuse for security reasons to permit (sender-initiated) SMTP transactions with sendmail.

   SUPPORT, TROUBLESHOOTING
       For troubleshooting, tracing and debugging, you need to increase fetchmail's verbosity  to
       actually  see  what  happens.  To  do that, please run both of the two following commands,
       adding all of the options you'd normally use.

              env LC_ALL=C fetchmail -V -v --nodetach --nosyslog

              (This command line prints in English how fetchmail understands your configuration.)

              env LC_ALL=C fetchmail -vvv  --nodetach --nosyslog

              (This command line actually runs fetchmail with verbose English output.)

       Also see item #G3 in fetchmail's FAQ ⟨http://fetchmail.berlios.de/fetchmail-FAQ.html#G3⟩

       You can omit the LC_ALL=C part above  if  you  want  output  in  the  local  language  (if
       supported).  However  if  you  are  posting  to  mailing  lists,  please  leave it in. The
       maintainers do not necessarily understand your language, please use English.

   CONCEPTS
       If fetchmail is used with a POP or an IMAP server (but not with ETRN or ODMR), it has  two
       fundamental  modes  of  operation  for  each  user  account  from which it retrieves mail:
       singledrop- and multidrop-mode.

       In singledrop-mode,
              fetchmail assumes that all messages in the user's account  (mailbox)  are  intended
              for  a  single recipient.  The identity of the recipient will either default to the
              local user currently executing fetchmail, or will need to be  explicitly  specified
              in the configuration file.

              fetchmail  uses singledrop-mode when the fetchmailrc configuration contains at most
              a single local user specification for a given server account.

       In multidrop-mode,
              fetchmail assumes that the mail server account actually contains mail intended  for
              any  number  of  different recipients.  Therefore, fetchmail must attempt to deduce
              the proper "envelope recipient" from the mail headers of  each  message.   In  this
              mode of operation, fetchmail almost resembles a mail transfer agent (MTA).

              Note that neither the POP nor IMAP protocols were intended for use in this fashion,
              and hence envelope information is often  not  directly  available.   The  ISP  must
              stores the envelope information in some message header and. The ISP must also store
              one copy of the  message  per  recipient.  If  either  of  the  conditions  is  not
              fulfilled,  this  process  is  unreliable,  because  fetchmail  must then resort to
              guessing the true envelope recipient(s)  of  a  message.  This  usually  fails  for
              mailing  list  messages  and  Bcc:d  mail,  or mail for multiple recipients in your
              domain.

              fetchmail uses multidrop-mode when more than one local user and/or  a  wildcard  is
              specified for a particular server account in the configuration file.

       In ETRN and ODMR modes,
              these  considerations  do  not  apply,  as these protocols are based on SMTP, which
              provides explicit envelope recipient information. These  protocols  always  support
              multiple recipients.

       As  each  message  is retrieved, fetchmail normally delivers it via SMTP to port 25 on the
       machine it is running on (localhost), just as though it were being passed in over a normal
       TCP/IP link.  fetchmail provides the SMTP server with an envelope recipient derived in the
       manner described previously.  The mail will then be  delivered  according  to  your  MTA's
       rules  (the Mail Transfer Agent is usually sendmail(8), exim(8), or postfix(8)).  Invoking
       your system's MDA (Mail Delivery Agent) is the duty of your MTA.  All the delivery-control
       mechanisms  (such  as .forward files) normally available through your system MTA and local
       delivery agents will therefore be applied as usual.

       If your fetchmail configuration sets a local MDA (see the --mda option), it will  be  used
       directly instead of talking SMTP to port 25.

       If  the program fetchmailconf is available, it will assist you in setting up and editing a
       fetchmailrc configuration.  It runs under the  X  window  system  and  requires  that  the
       language  Python  and the Tk toolkit (with Python bindings) be present on your system.  If
       you are first setting up fetchmail for single-user mode, it is recommended  that  you  use
       Novice  mode.  Expert mode provides complete control of fetchmail configuration, including
       the multidrop features.  In either case, the 'Autoprobe' button will  tell  you  the  most
       capable protocol a given mailserver supports, and warn you of potential problems with that
       server.

GENERAL OPERATION

       The behavior of fetchmail is controlled by command-line options and a  run  control  file,
       ~/.fetchmailrc,  the syntax of which we describe in a later section (this file is what the
       fetchmailconf program edits).  Command-line options override ~/.fetchmailrc declarations.

       Each server name that you specify following the  options  on  the  command  line  will  be
       queried.   If you don't specify any servers on the command line, each 'poll' entry in your
       ~/.fetchmailrc file will be queried.

       To facilitate the use of fetchmail in scripts and pipelines,  it  returns  an  appropriate
       exit code upon termination -- see EXIT CODES below.

       The following options modify the behavior of fetchmail.  It is seldom necessary to specify
       any of these once you have a working .fetchmailrc file set up.

       Almost all options have a corresponding keyword which can be used to  declare  them  in  a
       .fetchmailrc file.

       Some  special  options  are  not  covered  here, but are documented instead in sections on
       AUTHENTICATION and DAEMON MODE which follow.

   General Options
       -V | --version
              Displays the version information for your copy of  fetchmail.   No  mail  fetch  is
              performed.   Instead,  for  each  server specified, all the option information that
              would be computed if fetchmail were connecting to that server  is  displayed.   Any
              non-printables  in  passwords or other string names are shown as backslashed C-like
              escape sequences.  This option is useful for verifying that your  options  are  set
              the way you want them.

       -c | --check
              Return  a  status  code to indicate whether there is mail waiting, without actually
              fetching or deleting mail (see EXIT CODES below).  This  option  turns  off  daemon
              mode (in which it would be useless).  It doesn't play well with queries to multiple
              sites, and doesn't work with ETRN or ODMR.  It will return a false positive if  you
              leave  read but undeleted mail in your server mailbox and your fetch protocol can't
              tell kept messages from new ones.  This means it will work with IMAP, not work with
              POP2, and may occasionally flake out under POP3.

       -s | --silent
              Silent  mode.   Suppresses all progress/status messages that are normally echoed to
              standard output during a fetch (but does not suppress actual error messages).   The
              --verbose option overrides this.

       -v | --verbose
              Verbose mode.  All control messages passed between fetchmail and the mailserver are
              echoed to stdout.  Overrides --silent.  Doubling this option (-v -v)  causes  extra
              diagnostic information to be printed.

       --nosoftbounce
              (since v6.3.10, Keyword: set no softbounce, since v6.3.10)
              Hard  bounce  mode. All permanent delivery errors cause messages to be deleted from
              the upstream server, see "no softbounce" below.

       --softbounce
              (since v6.3.10, Keyword: set softbounce, since v6.3.10)
              Soft bounce mode. All permanent delivery errors cause messages to be  left  on  the
              upstream  server  if  the  protocol supports that.  This option is on by default to
              match historic fetchmail documentation, and will be changed to hard bounce mode  in
              the next fetchmail release.

   Disposal Options
       -a | --all | (since v6.3.3) --fetchall
              (Keyword: fetchall, since v3.0)
              Retrieve  both  old (seen) and new messages from the mailserver.  The default is to
              fetch only messages the server has not marked seen.  Under POP3, this  option  also
              forces the use of RETR rather than TOP.  Note that POP2 retrieval behaves as though
              --all is always on (see RETRIEVAL FAILURE MODES below) and  this  option  does  not
              work  with  ETRN  or ODMR.  While the -a and --all command-line and fetchall rcfile
              options have been supported for a long time, the --fetchall command-line option was
              added in v6.3.3.

       -k | --keep
              (Keyword: keep)
              Keep  retrieved  messages on the remote mailserver.  Normally, messages are deleted
              from the folder on the mailserver after they have been retrieved.   Specifying  the
              keep  option  causes retrieved messages to remain in your folder on the mailserver.
              This option does not work with ETRN or ODMR. If used with POP3, it  is  recommended
              to also specify the --uidl option or uidl keyword.

       -K | --nokeep
              (Keyword: nokeep)
              Delete retrieved messages from the remote mailserver.  This option forces retrieved
              mail to be deleted.  It may be useful if you have specified a default  of  keep  in
              your .fetchmailrc.  This option is forced on with ETRN and ODMR.

       -F | --flush
              (Keyword: flush)
              POP3/IMAP  only.   This  is  a  dangerous  option and can cause mail loss when used
              improperly. It deletes old (seen) messages from the  mailserver  before  retrieving
              new  messages.  Warning: This can cause mail loss if you check your mail with other
              clients than fetchmail, and cause fetchmail  to  delete  a  message  it  had  never
              fetched  before.   It can also cause mail loss if the mail server marks the message
              seen after retrieval (IMAP2 servers). You should probably not use  this  option  in
              your  configuration  file. If you use it with POP3, you must use the 'uidl' option.
              What you probably want is the default setting: if  you  don't  specify  '-k',  then
              fetchmail will automatically delete messages after successful delivery.

       --limitflush
              POP3/IMAP only, since version 6.3.0.  Delete oversized messages from the mailserver
              before retrieving new messages. The size limit should be separately specified  with
              the --limit option.  This option does not work with ETRN or ODMR.

   Protocol and Query Options
       -p <proto> | --proto <proto> | --protocol <proto>
              (Keyword: proto[col])
              Specify  the  protocol to use when communicating with the remote mailserver.  If no
              protocol is specified, the default is AUTO.  proto may be one of the following:

              AUTO   Tries IMAP, POP3, and POP2 (skipping any of these for which support has  not
                     been compiled in).

              POP2   Post Office Protocol 2 (legacy, to be removed from future release)

              POP3   Post Office Protocol 3

              APOP   Use  POP3  with  old-fashioned MD5-challenge authentication.  Considered not
                     resistant to man-in-the-middle attacks.

              RPOP   Use POP3 with RPOP authentication.

              KPOP   Use POP3 with Kerberos V4 authentication on port 1109.

              SDPS   Use POP3 with Demon Internet's SDPS extensions.

              IMAP   IMAP2bis,  IMAP4,  or  IMAP4rev1  (fetchmail  automatically  detects   their
                     capabilities).

              ETRN   Use the ESMTP ETRN option.

              ODMR   Use the the On-Demand Mail Relay ESMTP profile.

       All  these alternatives work in basically the same way (communicating with standard server
       daemons to fetch mail already delivered to a mailbox on the server) except ETRN and  ODMR.
       The  ETRN mode allows you to ask a compliant ESMTP server (such as BSD sendmail at release
       8.8.0 or higher) to immediately open a sender-SMTP connection to your client  machine  and
       begin  forwarding  any  items  addressed  to  your client machine in the server's queue of
       undelivered mail.   The ODMR mode requires an ODMR-capable server and works  similarly  to
       ETRN, except that it does not require the client machine to have a static DNS.

       -U | --uidl
              (Keyword: uidl)
              Force UIDL use (effective only with POP3).  Force client-side tracking of 'newness'
              of messages (UIDL stands for "unique ID listing" and is described in RFC1939).  Use
              with  'keep'  to  use  a mailbox as a baby news drop for a group of users. The fact
              that seen messages are skipped is logged, unless  error  logging  is  done  through
              syslog  while running in daemon mode.  Note that fetchmail may automatically enable
              this option depending on upstream server capabilities.  Note also that this  option
              may  be  removed  and  forced  enabled  in  a  future  fetchmail version. See also:
              --idfile.

       --idle (since 6.3.3)
              (Keyword: idle, since before 6.0.0)
              Enable IDLE use (effective only with IMAP). Note that  this  works  with  only  one
              folder  at  a  given  time.  While the idle rcfile keyword had been supported for a
              long time, the --idle command-line option was added  in  version  6.3.3.  IDLE  use
              means  that fetchmail tells the IMAP server to send notice of new messages, so they
              can be retrieved sooner than would be possible with regular polls.

       -P <portnumber> | --service <servicename>
              (Keyword: service) Since version 6.3.0.
              The service option permits you to specify a service name to connect  to.   You  can
              specify  a  decimal  port number here, if your services database lacks the required
              service-port assignments. See the FAQ item R12  and  the  --ssl  documentation  for
              details. This replaces the older --port option.

       --port <portnumber>
              (Keyword: port)
              Obsolete  version of --service that does not take service names.  Note: this option
              may be removed from a future version.

       --principal <principal>
              (Keyword: principal)
              The principal option  permits  you  to  specify  a  service  principal  for  mutual
              authentication.   This is applicable to POP3 or IMAP with Kerberos 4 authentication
              only.  It does not apply to Kerberos 5 or GSSAPI.  This option may be removed in  a
              future fetchmail version.

       -t <seconds> | --timeout <seconds>
              (Keyword: timeout)
              The timeout option allows you to set a server-nonresponse timeout in seconds.  If a
              mailserver does not send a greeting message or respond to commands  for  the  given
              number  of  seconds,  fetchmail  will  drop  the  connection to it.  Without such a
              timeout fetchmail might hang until the TCP connection times out,  trying  to  fetch
              mail from a down host, which may be very long.  This would be particularly annoying
              for a fetchmail running in the  background.   There  is  a  default  timeout  which
              fetchmail  -V  will  report.   If  a given connection receives too many timeouts in
              succession, fetchmail will consider it wedged and stop retrying.  The calling  user
              will be notified by email if this happens.

              Beginning  with  fetchmail  6.3.10,  the  SMTP  client uses the recommended minimum
              timeouts from RFC-5321 while waiting for the SMTP/LMTP server  it  is  talking  to.
              You can raise the timeouts even more, but you cannot shorten them. This is to avoid
              a painful situation where fetchmail has been configured with  a  short  timeout  (a
              minute  or  less),  ships a long message (many MBytes) to the local MTA, which then
              takes longer than timeout to respond "OK", which it  eventually  will;  that  would
              mean the mail gets delivered properly, but fetchmail cannot notice it and will thus
              refetch this big message over and over again.

       --plugin <command>
              (Keyword: plugin)
              The plugin option allows you to use  an  external  program  to  establish  the  TCP
              connection.   This  is  useful  if  you  want  to  use  ssh,  or  need some special
              firewalling setup.  The program will be looked up in $PATH and  can  optionally  be
              passed  the  hostname  and port as arguments using "%h" and "%p" respectively (note
              that the interpolation logic is rather primitive, and these tokens must be  bounded
              by  whitespace  or  beginning of string or end of string).  Fetchmail will write to
              the plugin's stdin and read from the plugin's stdout.

       --plugout <command>
              (Keyword: plugout)
              Identical to  the  plugin  option  above,  but  this  one  is  used  for  the  SMTP
              connections.

       -r <name> | --folder <name>
              (Keyword: folder[s])
              Causes  a  specified  non-default mail folder on the mailserver (or comma-separated
              list of folders) to be retrieved.   The  syntax  of  the  folder  name  is  server-
              dependent.  This option is not available under POP3, ETRN, or ODMR.

       --tracepolls
              (Keyword: tracepolls)
              Tell  fetchmail  to  poll  trace  information  in the form 'polling account %s' and
              'folder %s' to the Received line it generates, where the %s parts are  replaced  by
              the  user's  remote  name, the poll label, and the folder (mailbox) where available
              (the Received header also normally includes the server's true name).  This  can  be
              used  to  facilitate mail filtering based on the account it is being received from.
              The folder information is written only since version 6.3.4.

       --ssl  (Keyword: ssl)
              Causes the connection to the mail server to be encrypted via  SSL,  by  negotiating
              SSL  directly after connecting (SSL-wrapped mode).  It is highly recommended to use
              --sslcertck to validate the certificates presented by the server.  Please  see  the
              description  of  --sslproto below!  More information is available in the README.SSL
              file that ships with fetchmail.

              Note that even if this option is omitted, fetchmail may still negotiate SSL in-band
              for POP3 or IMAP, through the STLS or STARTTLS feature.  You can use the --sslproto
              option to modify that behavior.

              If no port is specified, the connection is attempted to the well known port of  the
              SSL version of the base protocol.  This is generally a different port than the port
              used by the base protocol.  For IMAP, this is port 143 for the clear  protocol  and
              port  993 for the SSL secured protocol; for POP3, it is port 110 for the clear text
              and port 995 for the encrypted variant.

              If your  system  lacks  the  corresponding  entries  from  /etc/services,  see  the
              --service  option  and  specify  the  numeric  port number as given in the previous
              paragraph (unless your ISP had directed you to different ports, which  is  uncommon
              however).

       --sslcert <name>
              (Keyword: sslcert)
              For  certificate-based  client  authentication.  Some SSL encrypted servers require
              client side keys and certificates for  authentication.   In  most  cases,  this  is
              optional.   This  specifies  the  location  of  the  public  key  certificate to be
              presented to the server at the time the SSL session  is  established.   It  is  not
              required  (but  may  be provided) if the server does not require it.  It may be the
              same file as the private key (combined key and certificate file) but  this  is  not
              recommended. Also see --sslkey below.

              NOTE:  If  you  use  client  authentication,  the  user  name  is  fetched from the
              certificate's CommonName and overrides the name set with --user.

       --sslkey <name>
              (Keyword: sslkey)
              Specifies the file name of the client side private SSL  key.   Some  SSL  encrypted
              servers  require  client  side  keys  and certificates for authentication.  In most
              cases, this is optional.  This specifies the location of the private  key  used  to
              sign  transactions  with the server at the time the SSL session is established.  It
              is not required (but may be provided) if the server does not require it. It may  be
              the same file as the public key (combined key and certificate file) but this is not
              recommended.

              If a password is required to unlock the key, it will be prompted for  at  the  time
              just  prior  to  establishing  the  session  to  the  server.   This can cause some
              complications in daemon mode.

              Also see --sslcert above.

       --sslproto <value>
              (Keyword: sslproto, NOTE: semantic changes since v6.4.0)
              This option has a dual use, out of historic fetchmail behaviour. It  controls  both
              the SSL/TLS protocol version and, if --ssl is not specified, the STARTTLS behaviour
              (upgrading the protocol to an SSL or TLS connection in-band).  Some  other  options
              may however make TLS mandatory.

       Only if this option and --ssl are both missing for a poll, there will be opportunistic TLS
       for POP3 and IMAP, where fetchmail will attempt to upgrade to TLSv1 or newer.

       Recognized values for --sslproto are given below. You should normally  chose  one  of  the
       auto-negotiating  options,  i.  e.  'auto'  or  one  of  the  options ending in a plus (+)
       character. Note that depending on OpenSSL library version and configuration, some  options
       cause  run-time  errors because the requested SSL or TLS versions are not supported by the
       particular installed OpenSSL library.

              '', the empty string
                     Disable STARTTLS. If --ssl is given for the same server, log  an  error  and
                     pretend that 'auto' had been used instead.

              'auto' (default). Since v6.4.0. Require TLS. Auto-negotiate TLSv1 or newer, disable
                     SSLv3 downgrade.  (fetchmail  6.3.26  and  older  have  auto-negotiated  all
                     protocols that their OpenSSL library supported, including the broken SSLv3).

              'SSL23'
                     see 'auto'.

              'SSL3' Require  SSLv3 exactly. SSLv3 is broken, not supported on all systems, avoid
                     it if possible.  This will make fetchmail negotiate SSLv3 only, and  is  the
                     only way besides 'SSL3+' to have fetchmail 6.4.0 or newer permit SSLv3.

              'SSL3+'
                     same  as  'auto',  but  permit  SSLv3  as well. This is the only way besides
                     'SSL3' to have fetchmail 6.4.0 or newer permit SSLv3.

              'TLS1' Require TLSv1. This does not negotiate TLSv1.1 or newer, and is discouraged.
                     Replace by TLS1+ unless the latter chokes your server.

              'TLS1+'
                     Since v6.4.0. See 'fBauto'.

              'TLS1.1'
                     Since v6.4.0. Require TLS v1.1 exactly.

              'TLS1.1+'
                     Since v6.4.0. Require TLS. Auto-negotiate TLSv1.1 or newer.

              'TLS1.2'
                     Since v6.4.0. Require TLS v1.2 exactly.

              'TLS1.2+'
                     Since v6.4.0. Require TLS. Auto-negotiate TLSv1.2 or newer.

              Unrecognized parameters
                     are treated the same as 'auto'.

              NOTE:  you  should  hardly  ever  need  to  use anything other than '' (to force an
              unencrypted connection) or 'auto' (to enforce TLS).

       --sslcertck
              (Keyword: sslcertck)
              Causes fetchmail to require that SSL/TLS be used  and  disconnect  if  it  can  not
              successfully negotiate SSL or TLS, or if it cannot successfully verify and validate
              the certificate and follow it to a trust anchor (or trusted root certificate).  The
              trust anchors are given as a set of local trusted certificates (see the sslcertfile
              and sslcertpath options). If the server certificate cannot be obtained  or  is  not
              signed  by  one  of  the  trusted  ones  (directly  or  indirectly), fetchmail will
              disconnect, regardless of the sslfingerprint option.

              Note that CRL (certificate revocation lists) are only supported  in  OpenSSL  0.9.7
              and  newer!  Your  system  clock should also be reasonably accurate when using this
              option.

              Note that this optional behavior may become default behavior  in  future  fetchmail
              versions.

       --sslcertfile <file>
              (Keyword: sslcertfile, since v6.3.17)
              Sets  the file fetchmail uses to look up local certificates.  The default is empty.
              This can be given in addition to --sslcertpath below, and certificates specified in
              --sslcertfile  will  be processed before those in --sslcertpath.  The option can be
              used in addition to --sslcertpath.

              The file is a text file. It contains the concatenation of trusted  CA  certificates
              in PEM format.

              Note  that  using  this  option  will  suppress  loading the default SSL trusted CA
              certificates    file    unless     you     set     the     environment     variable
              FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a non-empty value.

       --sslcertpath <directory>
              (Keyword: sslcertpath)
              Sets  the  directory  fetchmail  uses to look up local certificates. The default is
              your OpenSSL default directory. The  directory  must  be  hashed  the  way  OpenSSL
              expects  it - every time you add or modify a certificate in the directory, you need
              to use the c_rehash tool (which comes with OpenSSL  in  the  tools/  subdirectory).
              Also,  after  OpenSSL  upgrades,  you  may  need to run c_rehash; particularly when
              upgrading from 0.9.X to 1.0.0.

              This can be given in addition to --sslcertfile  above,  which  see  for  precedence
              rules.

              Note  that  using  this  option  will  suppress  adding  the default SSL trusted CA
              certificates    directory    unless    you    set    the    environment    variable
              FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a non-empty value.

       --sslcommonname <common name>
              (Keyword: sslcommonname; since v6.3.9)
              Use  of  this  option is discouraged. Before using it, contact the administrator of
              your upstream server and ask for a proper SSL  certificate  to  be  used.  If  that
              cannot  be  attained, this option can be used to specify the name (CommonName) that
              fetchmail expects on the server certificate.  A correctly  configured  server  will
              have this set to the hostname by which it is reached, and by default fetchmail will
              expect as much. Use this option when the CommonName is set to some other value,  to
              avoid  the  "Server  CommonName  mismatch" warning, and only if the upstream server
              can't be made to use proper certificates.

       --sslfingerprint <fingerprint>
              (Keyword: sslfingerprint)
              Specify the fingerprint of the server key (an MD5 hash of the key)  in  hexadecimal
              notation with colons separating groups of two digits. The letter hex digits must be
              in upper case. This is the format that fetchmail uses  to  report  the  fingerprint
              when  an  SSL  connection  is  established.  When this is specified, fetchmail will
              compare the server key fingerprint with the given one, and the connection will fail
              if they do not match, regardless of the sslcertck setting. The connection will also
              fail if fetchmail cannot obtain an SSL certificate from the server.   This  can  be
              used  to  prevent  man-in-the-middle  attacks, but the finger print from the server
              needs to be obtained or verified over a secure channel, and certainly not over  the
              same Internet connection that fetchmail would use.

              Using  this option will prevent printing certificate verification errors as long as
              --sslcertck is unset.

              To obtain the fingerprint of a certificate stored in the file cert.pem, try:

                   openssl x509 -in cert.pem -noout -md5 -fingerprint

              For details, see x509(1ssl).

   Delivery Control Options
       -S <hosts> | --smtphost <hosts>
              (Keyword: smtp[host])
              Specify a hunt list of hosts to forward mail to  (one  or  more  hostnames,  comma-
              separated).  Hosts  are  tried  in list order; the first one that is up becomes the
              forwarding  target  for  the  current  run.   If  this  option  is  not  specified,
              'localhost' is used as the default.  Each hostname may have a port number following
              the host name.  The port number is separated from the host name  by  a  slash;  the
              default port is "smtp".  If you specify an absolute path name (beginning with a /),
              it will be interpreted as the name of a  UNIX  socket  accepting  LMTP  connections
              (such as is supported by the Cyrus IMAP daemon) Example:

                   --smtphost server1,server2/2525,server3,/var/imap/socket/lmtp

              This option can be used with ODMR, and will make fetchmail a relay between the ODMR
              server and SMTP or LMTP receiver.

       --fetchdomains <hosts>
              (Keyword: fetchdomains)
              In ETRN or ODMR mode, this option specifies the list of domains the  server  should
              ship mail for once the connection is turned around.  The default is the FQDN of the
              machine running fetchmail.

       -D <domain> | --smtpaddress <domain>
              (Keyword: smtpaddress)
              Specify the domain to be appended to addresses in RCPT TO lines  shipped  to  SMTP.
              When  this  is  not  specified,  the  name  of  the  SMTP  server  (as specified by
              --smtphost) is used for SMTP/LMTP and 'localhost' is used for UNIX socket/BSMTP.

       --smtpname <user@domain>
              (Keyword: smtpname)
              Specify the domain and user to be put in  RCPT  TO  lines  shipped  to  SMTP.   The
              default user is the current local user.

       -Z <nnn> | --antispam <nnn[, nnn]...>
              (Keyword: antispam)
              Specifies  the  list  of  numeric SMTP errors that are to be interpreted as a spam-
              block response from the listener.  A value of -1 disables  this  option.   For  the
              command-line option, the list values should be comma-separated.

       -m <command> | --mda <command>
              (Keyword: mda)
              This  option  lets  fetchmail  use  a  Message or Local Delivery Agent (MDA or LDA)
              directly, rather than forward via SMTP or LMTP.

              To avoid losing mail, use this option only with MDAs like  maildrop  or  MTAs  like
              sendmail  that  exit  with a nonzero status on disk-full and other delivery errors;
              the nonzero status tells fetchmail that delivery failed and  prevents  the  message
              from being deleted on the server.

              If  fetchmail is running as root, it sets its user id while delivering mail through
              an MDA as  follows:   First,  the  FETCHMAILUSER,  LOGNAME,  and  USER  environment
              variables  are checked in this order. The value of the first variable from his list
              that is defined (even if it is empty!) is looked up in the system user database. If
              none  of  the  variables  is  defined,  fetchmail  will use the real user id it was
              started with. If one of the variables was defined, but the user stated there  isn't
              found, fetchmail continues running as root, without checking remaining variables on
              the list.  Practically,  this  means  that  if  you  run  fetchmail  as  root  (not
              recommended), it is most useful to define the FETCHMAILUSER environment variable to
              set the user that the MDA should run as. Some MDAs (such as maildrop) are  designed
              to  be  setuid  root  and  setuid  to  the  recipient's  user id, so you don't lose
              functionality this way even when running fetchmail as unprivileged user.  Check the
              MDA's manual for details.

              Some  possible  MDAs  are  "/usr/sbin/sendmail  -i -f %F -- %T" (Note: some several
              older or vendor sendmail versions  mistake  --  for  an  address,  rather  than  an
              indicator  to  mark  the  end  of  the  option  arguments),  "/usr/bin/deliver" and
              "/usr/bin/maildrop -d %T".  Local delivery addresses will be inserted into the  MDA
              command  wherever  you place a %T; the mail message's From address will be inserted
              where you place an %F.

              Do NOT enclose the %F or %T string in single quotes!  For both %T and %F, fetchmail
              encloses  the addresses in single quotes ('), after removing any single quotes they
              may contain, before the MDA command is passed to the shell.

              Do NOT use an MDA invocation that dispatches on the  contents  of  To/Cc/Bcc,  like
              "sendmail  -i  -t"  or "qmail-inject", it will create mail loops and bring the just
              wrath of many postmasters down upon your head.  This is one of  the  most  frequent
              configuration errors!

              Also,  do  not  try to combine multidrop mode with an MDA such as maildrop that can
              only accept one address, unless your upstream stores one copy of  the  message  per
              recipient and transports the envelope recipient in a header; you will lose mail.

              The  well-known  procmail(1)  package  is very hard to configure properly, it has a
              very nasty "fall through to the  next  rule"  behavior  on  delivery  errors  (even
              temporary  ones, such as out of disk space if another user's mail daemon copies the
              mailbox around to purge old messages), so your  mail  will  end  up  in  the  wrong
              mailbox  sooner or later. The proper procmail configuration is outside the scope of
              this document. Using maildrop(1) is usually much easier, and many  users  find  the
              filter syntax used by maildrop easier to understand.

              Finally,  we  strongly  advise  that you do not use qmail-inject.  The command line
              interface is non-standard without providing benefits for typical use, and fetchmail
              makes  no attempts to accommodate qmail-inject's deviations from the standard. Some
              of qmail-inject's command-line and environment options are actually  dangerous  and
              can cause broken threads, non-detected duplicate messages and forwarding loops.

       --lmtp (Keyword: lmtp)
              Cause  delivery  via  LMTP (Local Mail Transfer Protocol).  A service host and port
              must be explicitly specified on each host in the smtphost hunt list (see above)  if
              this option is selected; the default port 25 will (in accordance with RFC 2033) not
              be accepted.

       --bsmtp <filename>
              (Keyword: bsmtp)
              Append fetched mail to a BSMTP file.  This simply contains the SMTP  commands  that
              would  normally  be  generated  by  fetchmail when passing mail to an SMTP listener
              daemon.

              An argument of '-' causes the SMTP batch to be written to standard output, which is
              of  limited  use:  this only makes sense for debugging, because fetchmail's regular
              output is interspersed on the  same  channel,  so  this  isn't  suitable  for  mail
              delivery. This special mode may be removed in a later release.

              Note  that  fetchmail's  reconstruction  of  MAIL  FROM  and  RCPT  TO lines is not
              guaranteed correct; the caveats discussed under THE  USE  AND  ABUSE  OF  MULTIDROP
              MAILBOXES below apply.  This mode has precedence before --mda and SMTP/LMTP.

       --bad-header {reject|accept}
              (Keyword: bad-header; since v6.3.15)
              Specify how fetchmail is supposed to treat messages with bad headers, i. e. headers
              with bad syntax. Traditionally, fetchmail has  rejected  such  messages,  but  some
              distributors  modified  fetchmail to accept them. You can now configure fetchmail's
              behaviour per server.

   Resource Limit Control Options
       -l <maxbytes> | --limit <maxbytes>
              (Keyword: limit)
              Takes a maximum octet size argument, where 0 is the default and  also  the  special
              value  designating "no limit".  If nonzero, messages larger than this size will not
              be fetched and will be left on the server (in  foreground  sessions,  the  progress
              messages  will  note that they are "oversized").  If the fetch protocol permits (in
              particular, under IMAP or POP3 without the fetchall option) the message will not be
              marked seen.

              An  explicit  --limit  of 0 overrides any limits set in your run control file. This
              option is intended for  those  needing  to  strictly  control  fetch  time  due  to
              expensive and variable phone rates.

              Combined  with --limitflush, it can be used to delete oversized messages waiting on
              a server.  In daemon mode, oversize notifications are mailed to  the  calling  user
              (see the --warnings option). This option does not work with ETRN or ODMR.

       -w <interval> | --warnings <interval>
              (Keyword: warnings)
              Takes  an  interval  in  seconds.  When you call fetchmail with a 'limit' option in
              daemon mode, this controls the interval at which warnings about oversized  messages
              are  mailed to the calling user (or the user specified by the 'postmaster' option).
              One such notification is always mailed at the end of the the first  poll  that  the
              oversized  message  is  detected.   Thereafter, re-notification is suppressed until
              after the warning interval elapses (it will take place at  the  end  of  the  first
              following poll).

       -b <count> | --batchlimit <count>
              (Keyword: batchlimit)
              Specify  the  maximum  number  of messages that will be shipped to an SMTP listener
              before the connection is deliberately torn down and rebuilt (defaults to 0, meaning
              no  limit).   An  explicit  --batchlimit  of 0 overrides any limits set in your run
              control  file.   While  sendmail(8)  normally  initiates  delivery  of  a   message
              immediately  after receiving the message terminator, some SMTP listeners are not so
              prompt.  MTAs like smail(8) may wait till the  delivery  socket  is  shut  down  to
              deliver.   This may produce annoying delays when fetchmail is processing very large
              batches.  Setting the batch limit to some nonzero size will prevent  these  delays.
              This option does not work with ETRN or ODMR.

       -B <number> | --fetchlimit <number>
              (Keyword: fetchlimit)
              Limit  the  number  of  messages accepted from a given server in a single poll.  By
              default there is no limit. An explicit --fetchlimit of 0 overrides any  limits  set
              in your run control file.  This option does not work with ETRN or ODMR.

       --fetchsizelimit <number>
              (Keyword: fetchsizelimit)
              Limit  the  number  of  sizes  of messages accepted from a given server in a single
              transaction.  This option is useful in reducing the delay in downloading the  first
              mail  when  there are too many mails in the mailbox.  By default, the limit is 100.
              If set to 0, sizes of all messages are downloaded at the start.  This  option  does
              not work with ETRN or ODMR.  For POP3, the only valid non-zero value is 1.

       --fastuidl <number>
              (Keyword: fastuidl)
              Do a binary instead of linear search for the first unseen UID. Binary search avoids
              downloading the UIDs of all mails. This saves  time  (especially  in  daemon  mode)
              where  downloading  the  same set of UIDs in each poll is a waste of bandwidth. The
              number 'n' indicates how rarely a linear search should be  done.  In  daemon  mode,
              linear  search  is  used  once followed by binary searches in 'n-1' polls if 'n' is
              greater than 1; binary search is always used if 'n' is 1; linear search  is  always
              used  if 'n' is 0. In non-daemon mode, binary search is used if 'n' is 1; otherwise
              linear search is used. The default value of 'n' is 4.  This option works with  POP3
              only.

       -e <count> | --expunge <count>
              (Keyword: expunge)
              Arrange  for  deletions  to  be made final after a given number of messages.  Under
              POP2 or POP3, fetchmail cannot make deletions final without sending QUIT and ending
              the  session  --  with  this  option on, fetchmail will break a long mail retrieval
              session into multiple sub-sessions, sending QUIT after each sub-session. This is  a
              good  defense  against  line drops on POP3 servers.  Under IMAP, fetchmail normally
              issues an EXPUNGE command after each deletion in order to force the deletion to  be
              done  immediately.   This is safest when your connection to the server is flaky and
              expensive, as it avoids resending duplicate mail after a  line  hit.   However,  on
              large mailboxes the overhead of re-indexing after every message can slam the server
              pretty hard, so if your connection is reliable it  is  good  to  do  expunges  less
              frequently.   Also  note  that  some servers enforce a delay of a few seconds after
              each quit, so fetchmail may not be able to get back in immediately after an expunge
              -- you may see "lock busy" errors if this happens. If you specify this option to an
              integer N, it tells fetchmail to only issue  expunges  on  every  Nth  delete.   An
              argument  of  zero suppresses expunges entirely (so no expunges at all will be done
              until the end of run).  This option does not work with ETRN or ODMR.

   Authentication Options
       -u <name> | --user <name> | --username <name>
              (Keyword: user[name])
              Specifies the user identification to be used when logging  in  to  the  mailserver.
              The appropriate user identification is both server and user-dependent.  The default
              is your login name on the client machine  that  is  running  fetchmail.   See  USER
              AUTHENTICATION below for a complete description.

       -I <specification> | --interface <specification>
              (Keyword: interface)
              Require  that a specific interface device be up and have a specific local or remote
              IPv4 (IPv6 is not supported by this option yet) address (or range) before  polling.
              Frequently   fetchmail   is  used  over  a  transient  point-to-point  TCP/IP  link
              established directly to a mailserver via SLIP or PPP.  That is a relatively  secure
              channel.   But when other TCP/IP routes to the mailserver exist (e.g. when the link
              is connected to an alternate ISP), your username and password may be vulnerable  to
              snooping  (especially  when  daemon  mode  automatically polls for mail, shipping a
              clear password over the net at predictable intervals).  The --interface option  may
              be  used to prevent this.  When the specified link is not up or is not connected to
              a matching IP address, polling will be skipped.  The format is:

                   interface/iii.iii.iii.iii[/mmm.mmm.mmm.mmm]

              The field before the first slash is the interface name (i.e. sl0, ppp0 etc.).   The
              field  before  the  second slash is the acceptable IP address.  The field after the
              second slash is a mask which specifies a range of IP addresses to  accept.   If  no
              mask  is  present 255.255.255.255 is assumed (i.e. an exact match).  This option is
              currently only supported under Linux and FreeBSD. Please see  the  monitor  section
              for below for FreeBSD specific information.

              Note that this option may be removed from a future fetchmail version.

       -M <interface> | --monitor <interface>
              (Keyword: monitor)
              Daemon  mode  can  cause transient links which are automatically taken down after a
              period of inactivity (e.g. PPP links)  to  remain  up  indefinitely.   This  option
              identifies a system TCP/IP interface to be monitored for activity.  After each poll
              interval, if the link is up but no other activity has occurred on  the  link,  then
              the  poll  will  be  skipped.  However, when fetchmail is woken up by a signal, the
              monitor check is skipped and the poll goes through unconditionally.  This option is
              currently  only  supported  under Linux and FreeBSD.  For the monitor and interface
              options to work for non root users under FreeBSD,  the  fetchmail  binary  must  be
              installed  SGID  kmem.   This would be a security hole, but fetchmail runs with the
              effective GID set to that of the kmem group  only  when  interface  data  is  being
              collected.

              Note that this option may be removed from a future fetchmail version.

       --auth <type>
              (Keyword: auth[enticate])
              This  option permits you to specify an authentication type (see USER AUTHENTICATION
              below for details).  The possible values are any, password,  kerberos_v5,  kerberos
              (or,  for  excruciating  exactness,  kerberos_v4), gssapi, cram-md5, otp, ntlm, msn
              (only for POP3),  external  (only  IMAP)  and  ssh.   When  any  (the  default)  is
              specified,  fetchmail  tries first methods that don't require a password (EXTERNAL,
              GSSAPI, KERBEROS IV, KERBEROS 5); then it looks for methods that mask your password
              (CRAM-MD5,  NTLM,  X-OTP  -  note  that  MSN  is  only  supported for POP3, but not
              autoprobed); and only if the server doesn't support any of those will it ship  your
              password  en  clair.   Other  values  may  be  used to force various authentication
              methods (ssh suppresses authentication  and  is  thus  useful  for  IMAP  PREAUTH).
              (external  suppresses  authentication  and  is thus useful for IMAP EXTERNAL).  Any
              value other than password, cram-md5, ntlm, msn or otp suppresses fetchmail's normal
              inquiry  for  a  password.   Specify  ssh  when  you are using an end-to-end secure
              connection such as an ssh tunnel; specify external when you  use  TLS  with  client
              authentication  and  specify  gssapi  or  kerberos_v4  if  you are using a protocol
              variant that employs GSSAPI or K4.  Choosing KPOP  protocol  automatically  selects
              Kerberos  authentication.   This  option  does  not work with ETRN.  GSSAPI service
              names are in line with RFC-2743 and IANA registrations, see Generic Security
              Service Application Program Interface (GSSAPI)/Kerberos/Simple Authentication and
              Security Layer (SASL) Service Names ⟨http://www.iana.org/assignments/
              gssapi-service-names/⟩.

   Miscellaneous Options
       -f <pathname> | --fetchmailrc <pathname>
              Specify  a  non-default name for the ~/.fetchmailrc run control file.  The pathname
              argument must be either "-" (a single dash, meaning to read the configuration  from
              standard  input)  or  a  filename.  Unless the --version option is also on, a named
              file argument must have permissions no more open than 0700 (u=rwx,g=,o=) or else be
              /dev/null.

       -i <pathname> | --idfile <pathname>
              (Keyword: idfile)
              Specify  an  alternate name for the .fetchids file used to save message UIDs. NOTE:
              since fetchmail 6.3.0, write access to  the  directory  containing  the  idfile  is
              required, as fetchmail writes a temporary file and renames it into the place of the
              real idfile only if the temporary file has been written successfully.  This  avoids
              the truncation of idfiles when running out of disk space.

       --pidfile <pathname>
              (Keyword: pidfile; since fetchmail v6.3.4)
              Override the default location of the PID file. Default: see "ENVIRONMENT" below.

       -n | --norewrite
              (Keyword: no rewrite)
              Normally, fetchmail edits RFC-822 address headers (To, From, Cc, Bcc, and Reply-To)
              in fetched mail so that any mail IDs local to  the  server  are  expanded  to  full
              addresses  (@  and  the mailserver hostname are appended).  This enables replies on
              the client to get addressed correctly  (otherwise  your  mailer  might  think  they
              should  be  addressed to local users on the client machine!).  This option disables
              the rewrite.  (This option is provided to pacify  people  who  are  paranoid  about
              having  an  MTA  edit  mail headers and want to know they can prevent it, but it is
              generally not a good idea to actually turn off rewrite.)  When using ETRN or  ODMR,
              the rewrite option is ineffective.

       -E <line> | --envelope <line>
              (Keyword: envelope; Multidrop only)
              In the configuration file, an enhanced syntax is used:
              envelope [<count>] <line>

              This  option  changes  the header fetchmail assumes will carry a copy of the mail's
              envelope address.  Normally this is 'X-Envelope-To'.  Other typically found headers
              to  carry  envelope information are 'X-Original-To' and 'Delivered-To'.  Now, since
              these headers  are  not  standardized,  practice  varies.  See  the  discussion  of
              multidrop address handling below.  As a special case, 'envelope "Received"' enables
              parsing of sendmail-style Received lines.  This is  the  default,  but  discouraged
              because it is not fully reliable.

              Note  that  fetchmail expects the Received-line to be in a specific format: It must
              contain "by host for address", where host must match one of  the  mailserver  names
              that fetchmail recognizes for the account in question.

              The  optional  count argument (only available in the configuration file) determines
              how many header lines of this kind are skipped. A count of 1 means: skip the first,
              take the second. A count of 2 means: skip the first and second, take the third, and
              so on.

       -Q <prefix> | --qvirtual <prefix>
              (Keyword: qvirtual; Multidrop only)
              The string prefix assigned to this option will be removed from the user name  found
              in  the  header  specified  with  the  envelope option (before doing multidrop name
              mapping or localdomain checking, if either is applicable). This option is useful if
              you  are  using fetchmail to collect the mail for an entire domain and your ISP (or
              your mail redirection provider) is using qmail.  One of the basic features of qmail
              is  the Delivered-To: message header.  Whenever qmail delivers a message to a local
              mailbox it puts the username and hostname of the envelope recipient on  this  line.
              The  major reason for this is to prevent mail loops.  To set up qmail to batch mail
              for a disconnected site the ISP-mailhost will have normally put that  site  in  its
              'Virtualhosts'  control file so it will add a prefix to all mail addresses for this
              site. This results in mail sent  to  'username@userhost.userdom.dom.com'  having  a
              Delivered-To: line of the form:

              Delivered-To: mbox-userstr-username@userhost.example.com

       The ISP can make the 'mbox-userstr-' prefix anything they choose but a string matching the
       user host name is likely.  By using the  option  'envelope  Delivered-To:'  you  can  make
       fetchmail  reliably  identify  the  original envelope recipient, but you have to strip the
       'mbox-userstr-' prefix to deliver to the correct user.  This is what this option is for.

       --configdump
              Parse the ~/.fetchmailrc file, interpret any command-line  options  specified,  and
              dump a configuration report to standard output.  The configuration report is a data
              structure assignment in the language Python.  This option is meant to be used  with
              an interactive ~/.fetchmailrc editor like fetchmailconf, written in Python.

   Removed Options
       -T | --netsec
              Removed  before  version 6.3.0, the required underlying inet6_apps library had been
              discontinued and is no longer available.

USER AUTHENTICATION AND ENCRYPTION

       All modes except ETRN require authentication of the client to  the  server.   Normal  user
       authentication in fetchmail is very much like the authentication mechanism of ftp(1).  The
       correct user-id and password depend upon the underlying security system at the mailserver.

       If the mailserver is a Unix machine on which you  have  an  ordinary  user  account,  your
       regular  login  name and password are used with fetchmail.  If you use the same login name
       on both the server and the client machines, you needn't worry about specifying  a  user-id
       with the -u option -- the default behavior is to use your login name on the client machine
       as the user-id on the server machine.  If you use a different login  name  on  the  server
       machine,  specify that login name with the -u option.  e.g. if your login name is 'jsmith'
       on a machine named 'mailgrunt', you would start fetchmail as follows:

              fetchmail -u jsmith mailgrunt

       The default behavior of fetchmail is to prompt you for your mailserver password before the
       connection  is established.  This is the safest way to use fetchmail and ensures that your
       password  will  not  be  compromised.   You  may  also  specify  your  password  in   your
       ~/.fetchmailrc  file.   This  is  convenient  when  using fetchmail in daemon mode or with
       scripts.

   Using netrc files
       If  you  do  not  specify  a  password,  and  fetchmail  cannot  extract  one  from   your
       ~/.fetchmailrc  file,  it  will  look  for  a  ~/.netrc file in your home directory before
       requesting one interactively; if an entry matching the mailserver is found in  that  file,
       the  password  will  be used.  Fetchmail first looks for a match on poll name; if it finds
       none, it checks for a match on via name.  See the ftp(1)  man  page  for  details  of  the
       syntax of the ~/.netrc file.  To show a practical example, a .netrc might look like this:

              machine hermes.example.org
              login joe
              password topsecret

       You can repeat this block with different user information if you need to provide more than
       one password.

       This feature may allow you to avoid duplicating password  information  in  more  than  one
       file.

       On  mailservers  that do not provide ordinary user accounts, your user-id and password are
       usually assigned by the server administrator when you apply for a mailbox on  the  server.
       Contact  your  server administrator if you don't know the correct user-id and password for
       your mailbox account.

POP3 VARIANTS

       Early  versions  of  POP3  (RFC1081,  RFC1225)  supported  a  crude  form  of  independent
       authentication  using the .rhosts file on the mailserver side.  Under this RPOP variant, a
       fixed per-user ID equivalent to a password was sent in clear over a  link  to  a  reserved
       port, with the command RPOP rather than PASS to alert the server that it should do special
       checking.  RPOP is supported by fetchmail (you can specify 'protocol  RPOP'  to  have  the
       program  send  'RPOP' rather than 'PASS') but its use is strongly discouraged, and support
       will be removed from a future fetchmail version.  This facility was vulnerable to spoofing
       and was withdrawn in RFC1460.

       RFC1460  introduced  APOP  authentication.   In this variant of POP3, you register an APOP
       password on your server  host  (on  some  servers,  the  program  to  do  this  is  called
       popauth(8)).   You put the same password in your ~/.fetchmailrc file.  Each time fetchmail
       logs in, it sends an MD5 hash of your password and the server greeting time to the server,
       which can verify it by checking its authorization database.

       Note that APOP is no longer considered resistant against man-in-the-middle attacks.

   RETR or TOP
       fetchmail  makes  some efforts to make the server believe messages had not been retrieved,
       by using the TOP command with a large number of lines when possible.   TOP  is  a  command
       that  retrieves  the  full  header  and  a fetchmail-specified amount of body lines. It is
       optional and therefore not implemented by all servers, and some are known to implement  it
       improperly.  On  many  servers  however, the RETR command which retrieves the full message
       with header and body, sets the "seen" flag (for instance, in a web interface), whereas the
       TOP command does not do that.

       fetchmail  will always use the RETR command if "fetchall" is set.  fetchmail will also use
       the RETR command if "keep" is set and "uidl" is unset.  Finally, fetchmail  will  use  the
       RETR command on Maillennium POP3/PROXY servers (used by Comcast) to avoid a deliberate TOP
       misinterpretation in this server that causes message corruption.

       In all other cases, fetchmail will use the  TOP  command.  This  implies  that  in  "keep"
       setups, "uidl" must be set if "TOP" is desired.

       Note  that this description is true for the current version of fetchmail, but the behavior
       may change in future versions. In  particular,  fetchmail  may  prefer  the  RETR  command
       because the TOP command causes much grief on some servers and is only optional.

ALTERNATE AUTHENTICATION FORMS

       If  your fetchmail was built with Kerberos support and you specify Kerberos authentication
       (either with --auth or the .fetchmailrc option authenticate kerberos_v4) it  will  try  to
       get a Kerberos ticket from the mailserver at the start of each query.  Note: if either the
       pollname or via name is 'hesiod', fetchmail  will  try  to  use  Hesiod  to  look  up  the
       mailserver.

       If  you  use  POP3 or IMAP with GSSAPI authentication, fetchmail will expect the server to
       have RFC1731- or RFC1734-conforming GSSAPI capability, and will use  it.   Currently  this
       has only been tested over Kerberos V, so you're expected to already have a ticket-granting
       ticket. You may pass a username different from your  principal  name  using  the  standard
       --user command or by the .fetchmailrc option user.

       If  your  IMAP  daemon  returns  the PREAUTH response in its greeting line, fetchmail will
       notice this and skip the normal authentication step.  This can  be  useful,  e.g.  if  you
       start  imapd  explicitly using ssh.  In this case you can declare the authentication value
       'ssh' on that site entry to stop .fetchmail from asking you for a password when it  starts
       up.

       If  you use client authentication with TLS1 and your IMAP daemon returns the AUTH=EXTERNAL
       response, fetchmail will notice this and will use the authentication shortcut and will not
       send the passphrase. In this case you can declare the authentication value 'external'
        on that site to stop fetchmail from asking you for a password when it starts up.

       If  you  are using POP3, and the server issues a one-time-password challenge conforming to
       RFC1938, fetchmail will use your password as  a  pass  phrase  to  generate  the  required
       response. This avoids sending secrets over the net unencrypted.

       Compuserve's  RPA  authentication  is  supported. If you compile in the support, fetchmail
       will try to perform an RPA pass-phrase authentication instead of sending over the password
       en clair if it detects "@compuserve.com" in the hostname.

       If  you  are  using  IMAP, Microsoft's NTLM authentication (used by Microsoft Exchange) is
       supported. If you  compile  in  the  support,  fetchmail  will  try  to  perform  an  NTLM
       authentication (instead of sending over the password en clair) whenever the server returns
       AUTH=NTLM in its capability  response.  Specify  a  user  option  value  that  looks  like
       'user@domain':  the  part to the left of the @ will be passed as the username and the part
       to the right as the NTLM domain.

   Secure Socket Layers (SSL) and Transport Layer Security (TLS)
       transport. Additionally, POP3 and IMAP retrival can also negotiate  SSL/TLS  by  means  of
       STARTTLS (or STLS).

       Note that fetchmail currently uses the OpenSSL library, which is severely underdocumented,
       so failures may occur just because the programmers are not aware of OpenSSL's  requirement
       of  the  day.   For instance, since v6.3.16, fetchmail calls OpenSSL_add_all_algorithms(),
       which is necessary  to  support  certificates  using  SHA256  on  OpenSSL  0.9.8  --  this
       information  is  deeply hidden in the documentation and not at all obvious.  Please do not
       hesitate to report subtle SSL failures.

       You can access SSL encrypted services by specifying the options starting with --ssl,  such
       as  --ssl,  --sslproto,  --sslcertck,  and  others.   You  can  also  do  this  using  the
       corresponding user options in the .fetchmailrc file.  Some  services,  such  as  POP3  and
       IMAP,  have  different  well  known  ports  defined  for  the SSL encrypted services.  The
       encrypted ports will be selected automatically when SSL is enabled and no explicit port is
       specified.    Also,  the  --sslcertck  command  line  or sslcertck run control file option
       should be used to force strict certificate checking - see below.

       If SSL is not configured, fetchmail will usually opportunistically try  to  use  STARTTLS.
       STARTTLS  can  be  enforced  by using --sslproto auto and defeated by using --sslproto ''.
       TLS connections use the same port as the unencrypted version of the protocol and negotiate
       TLS via special command. The --sslcertck command line or sslcertck run control file option
       should be used to force strict certificate checking - see below.

       --sslcertck is recommended: When connecting to an SSL or TLS encrypted server, the  server
       presents a certificate to the client for validation.  The certificate is checked to verify
       that the common name in the certificate matches the name of the server being contacted and
       that  the  effective and expiration dates in the certificate indicate that it is currently
       valid.  If any of these checks fail, a warning message  is  printed,  but  the  connection
       continues.   The  server certificate does not need to be signed by any specific Certifying
       Authority and may be a "self-signed" certificate. If the --sslcertck command  line  option
       or sslcertck run control file option is used, fetchmail will instead abort if any of these
       checks fail, because it must assume that there  is  a  man-in-the-middle  attack  in  this
       scenario,  hence  fetchmail  must  not expose cleartext passwords. Use of the sslcertck or
       --sslcertck option is therefore advised.

       Some SSL encrypted servers may request a client side certificate.  A  client  side  public
       SSL  certificate  and  private  SSL key may be specified.  If requested by the server, the
       client certificate is sent to the server for validation.  Some servers may require a valid
       client  certificate  and may refuse connections if a certificate is not provided or if the
       certificate is not valid.  Some servers may require client side certificates be signed  by
       a recognized Certifying Authority.  The format for the key files and the certificate files
       is that required by the underlying SSL libraries (OpenSSL in the general case).

       A word of care about the use of SSL: While above mentioned setup with  self-signed  server
       certificates  retrieved  over  the  wires  can protect you from a passive eavesdropper, it
       doesn't help against an active attacker. It's clearly  an  improvement  over  sending  the
       passwords  in  clear, but you should be aware that a man-in-the-middle attack is trivially
       possible (in particular with tools such as dsniff ⟨http://monkey.org/~dugsong/dsniff/⟩, ).
       Use of strict certificate checking with a certification authority recognized by server and
       client, or perhaps of an SSH tunnel (see below for some examples)  is  preferable  if  you
       care seriously about the security of your mailbox and passwords.

   ESMTP AUTH
       fetchmail also supports authentication to the ESMTP server on the client side according to
       RFC 2554.  You can specify a name/password pair to be used with the  keywords  'esmtpname'
       and 'esmtppassword'; the former defaults to the username of the calling user.

DAEMON MODE

   Introducing the daemon mode
       In  daemon mode, fetchmail puts itself into the background and runs forever, querying each
       specified host and then sleeping for a given polling interval.

   Starting the daemon mode
       There are several ways to make fetchmail  work  in  daemon  mode.  On  the  command  line,
       --daemon <interval>  or  -d <interval>  option  runs  fetchmail  in daemon mode.  You must
       specify a numeric argument which is a polling interval (time to wait  after  completing  a
       whole  poll  cycle  with  the last server and before starting the next poll cycle with the
       first server) in seconds.

       Example: simply invoking

              fetchmail -d 900

       will, therefore, poll all the hosts described in your ~/.fetchmailrc  file  (except  those
       explicitly  excluded  with  the  'skip'  verb) a bit less often than once every 15 minutes
       (exactly: 15 minutes + time that the poll takes).

       It is also possible to set a polling  interval  in  your  ~/.fetchmailrc  file  by  saying
       'set daemon <interval>',  where  <interval>  is  an  integer number of seconds.  If you do
       this, fetchmail will always start in daemon mode unless you override it with the  command-
       line option --daemon 0 or -d0.

       Only  one  daemon  process is permitted per user; in daemon mode, fetchmail sets up a per-
       user lockfile to guarantee this.   (You  can  however  cheat  and  set  the  FETCHMAILHOME
       environment variable to overcome this setting, but in that case, it is your responsibility
       to make sure you aren't polling the same server with two processes at the same time.)

   Awakening the background daemon
       Normally, calling fetchmail with a daemon in the background sends a wake-up signal to  the
       daemon  and  quits  without  output. The background daemon then starts its next poll cycle
       immediately.  The wake-up signal, SIGUSR1, can also be sent manually. The  wake-up  action
       also  clears  any  'wedged'  flags  indicating  that connections have wedged due to failed
       authentication or multiple timeouts.

   Terminating the background daemon
       The option --quit will kill a running daemon process instead of waking it up (if there  is
       no  such  process,  fetchmail  will notify you).  If the --quit option appears last on the
       command line, fetchmail will kill the running daemon process  and  then  quit.  Otherwise,
       fetchmail  will  first  kill  a  running daemon process and then continue running with the
       other options.

   Useful options for daemon mode
       The -L <filename> or --logfile <filename> option (keyword: set logfile) is only  effective
       when  fetchmail  is  detached  and in daemon mode. Note that the logfile must exist before
       fetchmail is run, you can use the touch(1) command with the filename as its sole  argument
       to create it.
       This  option  allows  you to redirect status messages into a specified logfile (follow the
       option with the logfile name).  The logfile is opened for  append,  so  previous  messages
       aren't  deleted.   This  is  primarily  useful  for  debugging  configurations.  Note that
       fetchmail does not detect if the logfile is rotated, the logfile is only opened once  when
       fetchmail  starts.  You  need  to  restart fetchmail after rotating the logfile and before
       compressing it (if applicable).

       The --syslog option (keyword: set syslog) allows you to redirect status and error messages
       emitted  to  the  syslog(3) system daemon if available.  Messages are logged with an id of
       fetchmail, the facility LOG_MAIL, and priorities LOG_ERR,  LOG_ALERT  or  LOG_INFO.   This
       option  is intended for logging status and error messages which indicate the status of the
       daemon and the results while fetching mail from the server(s).  Error messages for command
       line  options  and  parsing  the  .fetchmailrc file are still written to stderr, or to the
       specified log file.  The --nosyslog option turns  off  use  of  syslog(3),  assuming  it's
       turned  on  in the ~/.fetchmailrc file.  This option is overridden, in certain situations,
       by --logfile (which see).

       The -N or --nodetach option suppresses backgrounding and detachment of the daemon  process
       from  its  control  terminal.   This is useful for debugging or when fetchmail runs as the
       child of a supervisor process such as init(8) or Gerrit Pape's runit(8).  Note  that  this
       also causes the logfile option to be ignored.

       Note that while running in daemon mode polling a POP2 or IMAP2bis server, transient errors
       (such as DNS failures or sendmail delivery refusals) may force the fetchall option on  for
       the duration of the next polling cycle.  This is a robustness feature.  It means that if a
       message is fetched (and thus marked seen by the mailserver) but not delivered locally  due
       to  some  transient  error,  it  will be re-fetched during the next poll cycle.  (The IMAP
       logic doesn't delete messages until they're delivered, so this problem does not arise.)

       If you touch or change the ~/.fetchmailrc file while fetchmail is running in daemon  mode,
       this  will  be  detected  at  the  beginning  of  the  next  poll  cycle.   When a changed
       ~/.fetchmailrc is detected, fetchmail rereads it and restarts from scratch (using exec(2);
       no  state  information  is retained in the new instance).  Note that if fetchmail needs to
       query for passwords, of that if you  break  the  ~/.fetchmailrc  file's  syntax,  the  new
       instance will softly and silently vanish away on startup.

ADMINISTRATIVE OPTIONS

       The  --postmaster  <name>  option  (keyword:  set  postmaster)  specifies  the last-resort
       username to which multidrop mail is to be forwarded if no matching local recipient can  be
       found.  It  is  also  used as destination of undeliverable mail if the 'bouncemail' global
       option is off and additionally for spam-blocked mail if the 'bouncemail' global option  is
       off and the 'spambounce' global option is on. This option defaults to the user who invoked
       fetchmail.  If the invoking user is root, then the default of  this  option  is  the  user
       'postmaster'.   Setting postmaster to the empty string causes such mail as described above
       to be discarded - this however is usually a bad idea.  See also  the  description  of  the
       'FETCHMAILUSER' environment variable in the ENVIRONMENT section below.

       The --nobounce behaves like the "set no bouncemail" global option, which see.

       The  --invisible  option  (keyword:  set  invisible)  tries  to  make fetchmail invisible.
       Normally, fetchmail behaves like any other MTA would -- it  generates  a  Received  header
       into  each message describing its place in the chain of transmission, and tells the MTA it
       forwards to that the mail came from the machine fetchmail itself is running  on.   If  the
       invisible option is on, the Received header is suppressed and fetchmail tries to spoof the
       MTA it forwards to into thinking it came directly from the mailserver host.

       The --showdots option (keyword: set showdots) forces fetchmail to show progress dots  even
       if  the  output  goes  to a file or fetchmail is not in verbose mode.  Fetchmail shows the
       dots by default when run in --verbose mode and output goes  to  console.  This  option  is
       ignored in --silent mode.

       By  specifying  the  --tracepolls  option, you can ask fetchmail to add information to the
       Received header on the form "polling {label} account {user}", where {label} is the account
       label  (from  the  specified  rcfile,  normally ~/.fetchmailrc) and {user} is the username
       which is used to log on to the mail server. This header can  be  used  to  make  filtering
       email  where  no  useful  header information is available and you want mail from different
       accounts sorted into different mailboxes (this could, for example, occur if  you  have  an
       account  on  the  same server running a mailing list, and are subscribed to the list using
       that account). The default is not adding any such header.  In .fetchmailrc, this is called
       'tracepolls'.

RETRIEVAL FAILURE MODES

       The  protocols  fetchmail  uses to talk to mailservers are next to bulletproof.  In normal
       operation forwarding to port 25, no message is ever deleted (or even marked for  deletion)
       on  the host until the SMTP listener on the client side has acknowledged to fetchmail that
       the message has been either accepted for delivery or rejected due to a spam block.

       When forwarding to an MDA, however, there is more possibility of  error.   Some  MDAs  are
       'safe'  and  reliably  return  a  nonzero  status  on  any delivery error, even one due to
       temporary resource limits.  The maildrop(1) program is like this;  so  are  most  programs
       designed  as mail transport agents, such as sendmail(1), including the sendmail wrapper of
       Postfix and exim(1).  These programs give back a reliable positive acknowledgement and can
       be  used with the mda option with no risk of mail loss.  Unsafe MDAs, though, may return 0
       even on delivery failure.  If this happens, you will lose mail.

       The normal mode of fetchmail is to try to download only 'new' messages, leaving  untouched
       (and  undeleted)  messages you have already read directly on the server (or fetched with a
       previous fetchmail --keep).  But you may find that messages you've  already  read  on  the
       server  are  being  fetched  (and  deleted)  even when you don't specify --all.  There are
       several reasons this can happen.

       One could be that you're using POP2.  The POP2  protocol  includes  no  representation  of
       'new'  or  'old'  state  in  messages, so fetchmail must treat all messages as new all the
       time.  But POP2 is obsolete, so this is unlikely.

       A potential POP3 problem might be servers that insert messages in the middle of  mailboxes
       (some  VMS  implementations  of  mail are rumored to do this).  The fetchmail code assumes
       that new messages are appended to the end of the mailbox; when this is  not  true  it  may
       treat some old messages as new and vice versa.  Using UIDL whilst setting fastuidl 0 might
       fix this, otherwise, consider switching to IMAP.

       Yet another POP3 problem is  that  if  they  can't  make  tempfiles  in  the  user's  home
       directory, some POP3 servers will hand back an undocumented response that causes fetchmail
       to spuriously report "No mail".

       The IMAP code uses the presence or absence of the server flag \Seen to decide  whether  or
       not  a  message  is  new.   This  isn't  the right thing to do, fetchmail should check the
       UIDVALIDITY and use UID, but it doesn't do that yet. Under Unix, it counts  on  your  IMAP
       server to notice the BSD-style Status flags set by mail user agents and set the \Seen flag
       from them when appropriate.  All Unix IMAP servers we know of do  this,  though  it's  not
       specified by the IMAP RFCs.  If you ever trip over a server that doesn't, the symptom will
       be that messages you have already read on your host will look new to the server.  In  this
       (unlikely)  case,  only  messages you fetched with fetchmail --keep will be both undeleted
       and marked old.

       In ETRN and ODMR modes, fetchmail does not actually retrieve messages;  instead,  it  asks
       the  server's  SMTP  listener to start a queue flush to the client via SMTP.  Therefore it
       sends only undelivered messages.

SPAM FILTERING

       Many SMTP listeners allow administrators to set up 'spam filters' that  block  unsolicited
       email  from  specified  domains.  A MAIL FROM or DATA line that triggers this feature will
       elicit an SMTP response which (unfortunately) varies according to the listener.

       Newer versions of sendmail return an error code of 571.

       According to RFC2821, the correct thing to return in  this  situation  is  550  "Requested
       action  not  taken:  mailbox  unavailable"  (the  draft adds "[E.g., mailbox not found, no
       access, or command rejected for policy reasons].").

       Older versions of the exim MTA return 501 "Syntax error in parameters or arguments".

       The postfix MTA runs 554 as an antispam response.

       Zmailer may reject code with a 500 response (followed by  an  enhanced  status  code  that
       contains more information).

       Return  codes which fetchmail treats as antispam responses and discards the message can be
       set with the 'antispam' option.  This is one of the only three  circumstance  under  which
       fetchmail  ever  discards mail (the others are the 552 and 553 errors described below, and
       the suppression of multidropped messages with a message-ID already seen).

       If fetchmail is fetching from an IMAP server, the antispam response will be  detected  and
       the  message rejected immediately after the headers have been fetched, without reading the
       message body.  Thus, you won't pay for downloading spam message bodies.

       By default, the list of antispam responses is empty.

       If  the  spambounce  global  option  is  on,  mail  that  is  spam-blocked   triggers   an
       RFC1892/RFC1894  bounce  message  informing the originator that we do not accept mail from
       it. See also BUGS.

SMTP/ESMTP ERROR HANDLING

       Besides the spam-blocking described above, fetchmail takes special actions — that  may  be
       modified by the --softbounce option — on the following SMTP/ESMTP error response codes

       452 (insufficient system storage)
            Leave the message in the server mailbox for later retrieval.

       552 (message exceeds fixed maximum message size)
            Delete the message from the server.  Send bounce-mail to the originator.

       553 (invalid sending domain)
            Delete  the  message  from  the  server.   Don't  even try to send bounce-mail to the
            originator.

       Other errors greater or equal to 500 trigger bounce mail back to  the  originator,  unless
       suppressed by --softbounce. See also BUGS.

THE RUN CONTROL FILE

       The  preferred  way  to  set  up  fetchmail  is  to write a .fetchmailrc file in your home
       directory (you may do this directly, with a text editor, or indirectly via fetchmailconf).
       When  there  is  a  conflict  between the command-line arguments and the arguments in this
       file, the command-line arguments take precedence.

       To protect the security of your passwords, your ~/.fetchmailrc may not normally have  more
       than  0700  (u=rwx,g=,o=)  permissions;  fetchmail  will complain and exit otherwise (this
       check is suppressed when --version is on).

       You may read the .fetchmailrc file as a list of commands to be executed when fetchmail  is
       called with no arguments.

   Run Control Syntax
       Comments  begin  with  a  '#'  and extend through the end of the line.  Otherwise the file
       consists of a series of server entries or  global  option  statements  in  a  free-format,
       token-oriented syntax.

       There  are four kinds of tokens: grammar keywords, numbers (i.e. decimal digit sequences),
       unquoted strings, and quoted strings.  A quoted string is bounded by double quotes and may
       contain  whitespace (and quoted digits are treated as a string).  Note that quoted strings
       will also contain line feed characters if they run across two or more  lines,  unless  you
       use a backslash to join lines (see below).  An unquoted string is any whitespace-delimited
       token that is neither numeric, string quoted nor contains the special characters ',', ';',
       ':', or '='.

       Any amount of whitespace separates tokens in server entries, but is otherwise ignored. You
       may use backslash escape sequences (\n for LF, \t for HT, \b for BS, \r for CR,  \nnn  for
       decimal  (where  nnn  cannot  start with a 0), \0ooo for octal, and \xhh for hex) to embed
       non-printable characters or string delimiters in strings.  In quoted strings, a  backslash
       at the very end of a line will cause the backslash itself and the line feed (LF or NL, new
       line) character to be ignored, so that you can wrap long strings. Without the backslash at
       the line end, the line feed character would become part of the string.

       Warning:  while these resemble C-style escape sequences, they are not the same.  fetchmail
       only supports these eight styles.  C  supports  more  escape  sequences  that  consist  of
       backslash  (\)  and  a  single  character, but does not support decimal codes and does not
       require the leading 0 in octal notation.  Example: fetchmail interprets \233 the  same  as
       \xE9  (Latin small letter e with acute), where C would interpret \233 as octal 0233 = \x9B
       (CSI, control sequence introducer).

       Each server entry consists of one of the keywords 'poll' or 'skip', followed by  a  server
       name,  followed  by  server  options,  followed  by  any  number  of  user  (or  username)
       descriptions, followed by user options.  Note: the most common cause of syntax  errors  is
       mixing up user and server options or putting user options before the user descriptions.

       For backward compatibility, the word 'server' is a synonym for 'poll'.

       You can use the noise keywords 'and', 'with', 'has', 'wants', and 'options' anywhere in an
       entry to make it resemble English.  They're ignored, but but can make entries much  easier
       to read at a glance.  The punctuation characters ':', ';' and ',' are also ignored.

   Poll vs. Skip
       The  'poll' verb tells fetchmail to query this host when it is run with no arguments.  The
       'skip' verb tells fetchmail not to poll this host unless it is  explicitly  named  on  the
       command  line.   (The  'skip'  verb  allows you to experiment with test entries safely, or
       easily disable entries for hosts that are temporarily down.)

   Keyword/Option Summary
       Here are the legal options.  Keyword suffixes enclosed in square  brackets  are  optional.
       Those  corresponding to short command-line options are followed by '-' and the appropriate
       option letter.  If option is only relevant to a single mode of operation, it is  noted  as
       's' or 'm' for singledrop- or multidrop-mode, respectively.

       Here are the legal global options:

       Keyword             Opt   Mode   Function
       ────────────────────────────────────────────────────────────────────
       set daemon          -d           Set  a background poll interval in
                                        seconds.
       set postmaster                   Give the name of  the  last-resort
                                        mail   recipient   (default:  user
                                        running fetchmail, "postmaster" if
                                        run by the root user)
       set    bouncemail                Direct  error  mail  to the sender
                                        (default)
       set no bouncemail                Direct error  mail  to  the  local
                                        postmaster     (as     per     the
                                        'postmaster' global option above).
       set no spambounce                Do not  bounce  spam-blocked  mail
                                        (default).
       set    spambounce                Bounce  blocked  spam-blocked mail
                                        (as  per   the   'antispam'   user
                                        option) back to the destination as
                                        indicated  by   the   'bouncemail'
                                        global  option.   Warning:  Do not
                                        use this to bounce  spam  back  to
                                        the  sender  -  most  spam is sent
                                        with false sender address and thus
                                        this    option    hurts   innocent
                                        bystanders.
       set no softbounce                Delete  permanently  undeliverable
                                        mail.  It  is  recommended  to use
                                        this option if  the  configuration
                                        has been thoroughly tested.
       set    softbounce                Keep   permanently   undeliverable
                                        mail as though a  temporary  error
                                        had occurred (default).
       set logfile         -L           Name of a file to append error and
                                        status    messages    to.     Only
                                        effective  in  daemon  mode and if
                                        fetchmail detaches.  If effective,
                                        overrides set syslog.
       set idfile          -i           Name  of  the  file  to  store UID
                                        lists in.
       set    syslog                    Do    error    logging     through
                                        syslog(3). May be overriden by set
                                        logfile.

       set no syslog                    Turn  off  error  logging  through
                                        syslog(3). (default)
       set properties                   String  value  that  is ignored by
                                        fetchmail   (may   be   used    by
                                        extension scripts).

       Here are the legal server options:

       Keyword          Opt   Mode   Function
       ─────────────────────────────────────────────────────────────────
       via                           Specify  DNS  name  of mailserver,
                                     overriding poll name
       proto[col]       -p           Specify       protocol       (case
                                     insensitive):  POP2,  POP3,  IMAP,
                                     APOP, KPOP
       local[domains]         m      Specify domain(s) to  be  regarded
                                     as local
       port                          Specify    TCP/IP   service   port
                                     (obsolete, use 'service' instead).
       service          -P           Specify service  name  (a  numeric
                                     value    is   also   allowed   and
                                     considered a TCP/IP port number).
       auth[enticate]                Set authentication  type  (default
                                     'any')
       timeout          -t           Server   inactivity   timeout   in
                                     seconds (default 300)
       envelope         -E    m      Specify  envelope-address   header
                                     name
       no envelope            m      Disable   looking   for   envelope
                                     address
       qvirtual         -Q    m      Qmail  virtual  domain  prefix  to
                                     remove from user name
       aka                    m      Specify  alternate  DNS  names  of
                                     mailserver
       interface        -I           specify IP interface(s) that  must
                                     be  up  for  server  poll  to take
                                     place
       monitor          -M           Specify IP address to monitor  for
                                     activity
       plugin                        Specify  command  through which to
                                     make server connections.
       plugout                       Specify command through  which  to
                                     make listener connections.
       dns                    m      Enable  DNS  lookup  for multidrop
                                     (default)
       no dns                 m      Disable DNS lookup for multidrop
       checkalias             m      Do comparison by  IP  address  for
                                     multidrop
       no checkalias          m      Do    comparison   by   name   for
                                     multidrop (default)
       uidl             -U           Force  POP3  to  use   client-side
                                     UIDLs (recommended)
       no uidl                       Turn  off  POP3 use of client-side
                                     UIDLs (default)
       interval                      Only check this site every N  poll
                                     cycles; N is a numeric argument.
       tracepolls                    Add  poll  tracing  information to
                                     the Received header
       principal                     Set   Kerberos   principal   (only
                                     useful with IMAP and kerberos)
       esmtpname                     Set      name      for     RFC2554
                                     authentication   to   the    ESMTP
                                     server.
       esmtppassword                 Set     password    for    RFC2554
                                     authentication   to   the    ESMTP
                                     server.

       bad-header                    How  to  treat messages with a bad
                                     header. Can be reject (default) or
                                     accept.

       Here are the legal user descriptions and options:

       Keyword            Opt   Mode   Function
       ───────────────────────────────────────────────────────────────────
       user[name]         -u           This  is  the user description and
                                       must  come  first   after   server
                                       description   and  after  possible
                                       server options,  and  before  user
                                       options.
                                       It sets the remote user name if by
                                       itself or followed by 'there',  or
                                       the local user name if followed by
                                       'here'.
       is                              Connect  local  and  remote   user
                                       names
       to                              Connect   local  and  remote  user
                                       names
       pass[word]                      Specify remote account password
       ssl                             Connect   to   server   over   the
                                       specified  base protocol using SSL
                                       encryption
       sslcert                         Specify  file  for   client   side
                                       public SSL certificate
       sslcertfile                     Specify   file   with  trusted  CA
                                       certificates
       sslcertpath                     Specify c_rehash-ed directory with
                                       trusted CA certificates.
       sslkey                          Specify   file   for  client  side
                                       private SSL key
       sslproto                        Force ssl protocol for connection
       folder             -r           Specify remote folder to query
       smtphost           -S           Specify smtp host(s) to forward to
       fetchdomains             m      Specify  domains  for  which  mail
                                       should be fetched
       smtpaddress        -D           Specify  the  domain  to be put in
                                       RCPT TO lines
       smtpname                        Specify the user and domain to  be
                                       put in RCPT TO lines
       antispam           -Z           Specify   what  SMTP  returns  are
                                       interpreted as spam-policy blocks
       mda                -m           Specify MDA for local delivery
       bsmtp              -o           Specify BSMTP batch file to append
                                       to
       preconnect                      Command to be executed before each
                                       connection
       postconnect                     Command to be executed after  each
                                       connection
       keep               -k           Don't  delete  seen  messages from
                                       server   (for   POP3,   uidl    is
                                       recommended)
       flush              -F           Flush  all  seen  messages  before
                                       querying (DANGEROUS)
       limitflush                      Flush   all   oversized   messages
                                       before querying
       fetchall           -a           Fetch all messages whether seen or
                                       not
       rewrite                         Rewrite destination addresses  for
                                       reply (default)
       stripcr                         Strip  carriage  returns from ends
                                       of lines
       forcecr                         Force carriage returns at ends  of
                                       lines

       pass8bits                       Force   BODY=8BITMIME   to   ESMTP
                                       listener
       dropstatus                      Strip Status and  X-Mozilla-Status
                                       lines out of incoming mail
       dropdelivered                   Strip  Delivered-To  lines  out of
                                       incoming mail
       mimedecode                      Convert quoted-printable to  8-bit
                                       in MIME messages
       idle                            Idle   waiting  for  new  messages
                                       after each poll (IMAP only)
       no keep            -K           Delete seen messages  from  server
                                       (default)
       no flush                        Don't   flush  all  seen  messages
                                       before querying (default)
       no fetchall                     Retrieve   only    new    messages
                                       (default)
       no rewrite                      Don't rewrite headers
       no stripcr                      Don't   strip   carriage   returns
                                       (default)
       no forcecr                      Don't force  carriage  returns  at
                                       EOL (default)
       no pass8bits                    Don't force BODY=8BITMIME to ESMTP
                                       listener (default)
       no dropstatus                   Don't    drop    Status    headers
                                       (default)
       no dropdelivered                Don't  drop  Delivered-To  headers
                                       (default)
       no mimedecode                   Don't convert quoted-printable  to
                                       8-bit in MIME messages (default)
       no idle                         Don't   idle   waiting   for   new
                                       messages  after  each  poll  (IMAP
                                       only)
       limit              -l           Set message size limit
       warnings           -w           Set message size warning interval
       batchlimit         -b           Max   #  messages  to  forward  in
                                       single connect
       fetchlimit         -B           Max # messages to fetch in  single
                                       connect
       fetchsizelimit                  Max  #  message  sizes to fetch in
                                       single transaction
       fastuidl                        Use binary search for first unseen
                                       message (POP3 only)
       expunge            -e           Perform  an  expunge  on every #th
                                       message (IMAP and POP3 only)
       properties                      String   value   is   ignored   by
                                       fetchmail    (may   be   used   by
                                       extension scripts)

       All user options must begin with a user description (user or username option)  and  follow
       all server descriptions and options.

       In  the .fetchmailrc file, the 'envelope' string argument may be preceded by a whitespace-
       separated number.  This number, if specified, is the number of such headers to  skip  over
       (that is, an argument of 1 selects the second header of the given type).  This is sometime
       useful for ignoring bogus envelope headers created by an ISP's  local  delivery  agent  or
       internal forwards (through mail inspection systems, for instance).

   Keywords Not Corresponding To Option Switches
       The  'folder'  and  'smtphost'  options (unlike their command-line equivalents) can take a
       space- or comma-separated list of names following them.

       All options correspond to the obvious command-line arguments, except the following: 'via',
       'interval',  'aka',  'is', 'to', 'dns'/'no dns', 'checkalias'/'no checkalias', 'password',
       'preconnect',  'postconnect',  'localdomains',   'stripcr'/'no   stripcr',   'forcecr'/'no
       forcecr',   'pass8bits'/'no   pass8bits'   'dropstatus/no  dropstatus',  'dropdelivered/no
       dropdelivered', 'mimedecode/no mimedecode', 'no idle', and 'no envelope'.

       The 'via' option is for if you want to have more than one configuration  pointing  at  the
       same  site.  If it is present, the string argument will be taken as the actual DNS name of
       the mailserver host to query.  This will override the argument of  poll,  which  can  then
       simply  be a distinct label for the configuration (e.g. what you would give on the command
       line to explicitly query this host).

       The 'interval' option (which takes a numeric argument) allows you to poll  a  server  less
       frequently  than  the basic poll interval.  If you say 'interval N' the server this option
       is attached to will only be queried every N poll intervals.

   Singledrop vs. Multidrop options
       Please ensure you read the section titled THE USE AND ABUSE OF MULTIDROP MAILBOXES if  you
       intend to use multidrop mode.

       The  'is'  or 'to' keywords associate the following local (client) name(s) (or server-name
       to client-name mappings separated by =) with the mailserver user name in the entry.  If an
       is/to  list  has  '*' as its last name, unrecognized names are simply passed through. Note
       that until fetchmail version 6.3.4 inclusively, these lists could only contain local parts
       of  user  names  (fetchmail  would  only  look  at  the part before the @ sign). fetchmail
       versions 6.3.5 and newer support full addresses on the left hand side of  these  mappings,
       and they take precedence over any 'localdomains', 'aka', 'via' or similar mappings.

       A single local name can be used to support redirecting your mail when your username on the
       client machine is different from your name on the mailserver.  When there is only a single
       local name, mail is forwarded to that local username regardless of the message's Received,
       To, Cc, and Bcc headers.  In this case, fetchmail never does DNS lookups.

       When there is more than one local name (or name mapping), fetchmail looks at the  envelope
       header, if configured, and otherwise at the Received, To, Cc, and Bcc headers of retrieved
       mail (this is 'multidrop mode').  It looks for addresses with hostname  parts  that  match
       your  poll  name  or  your  'via',  'aka'  or 'localdomains' options, and usually also for
       hostname parts which DNS tells it are aliases of the mailserver.  See  the  discussion  of
       'dns',  'checkalias',  'localdomains', and 'aka' for details on how matching addresses are
       handled.

       If fetchmail cannot match any mailserver usernames or localdomain addresses, the mail will
       be  bounced.   Normally  it  will be bounced to the sender, but if the 'bouncemail' global
       option is off, the mail will go to the local postmaster instead.   (see  the  'postmaster'
       global option). See also BUGS.

       The  'dns'  option  (normally  on) controls the way addresses from multidrop mailboxes are
       checked.  On, it enables logic to check each host address that does not match an 'aka'  or
       'localdomains'  declaration  by  looking  it  up  with DNS.  When a mailserver username is
       recognized attached to a matching hostname part, its local mapping is added to the list of
       local recipients.

       The  'checkalias' option (normally off) extends the lookups performed by the 'dns' keyword
       in multidrop mode, providing a way to cope with remote MTAs that identify themselves using
       their  canonical name, while they're polled using an alias.  When such a server is polled,
       checks to extract the envelope address fail, and fetchmail reverts to delivery  using  the
       To/Cc/Bcc  headers  (See  below  'Header vs. Envelope addresses').  Specifying this option
       instructs fetchmail to retrieve all the IP addresses associated with both  the  poll  name
       and  the  name  used  by  the remote MTA and to do a comparison of the IP addresses.  This
       comes in handy in situations where the remote server  undergoes  frequent  canonical  name
       changes,  that  would  otherwise require modifications to the rcfile.  'checkalias' has no
       effect if 'no dns' is specified in the rcfile.

       The 'aka' option is for use with multidrop mailboxes.  It allows you to pre-declare a list
       of  DNS aliases for a server.  This is an optimization hack that allows you to trade space
       for speed.  When fetchmail, while processing a multidrop mailbox, grovels through  message
       headers  looking  for  names of the mailserver, pre-declaring common ones can save it from
       having to do DNS lookups.  Note: the names you give as arguments to 'aka' are  matched  as
       suffixes  --  if  you  specify (say) 'aka netaxs.com', this will match not just a hostname
       netaxs.com, but any hostname that ends with '.netaxs.com'; such as  (say)  pop3.netaxs.com
       and mail.netaxs.com.

       The  'localdomains'  option allows you to declare a list of domains which fetchmail should
       consider local.  When fetchmail is  parsing  address  lines  in  multidrop  modes,  and  a
       trailing  segment  of  a host name matches a declared local domain, that address is passed
       through to the listener or MDA unaltered (local-name mappings are not applied).

       If you are using 'localdomains', you  may  also  need  to  specify  'no  envelope',  which
       disables  fetchmail's  normal attempt to deduce an envelope address from the Received line
       or X-Envelope-To header or whatever header has been previously set by 'envelope'.  If  you
       set  'no envelope' in the defaults entry it is possible to undo that in individual entries
       by using 'envelope <string>'.  As a  special  case,  'envelope  "Received"'  restores  the
       default parsing of Received lines.

       The  password option requires a string argument, which is the password to be used with the
       entry's server.

       The 'preconnect' keyword allows you to specify a shell command to be executed just  before
       each  time  fetchmail  establishes a mailserver connection.  This may be useful if you are
       attempting to set up secure POP connections with  the  aid  of  ssh(1).   If  the  command
       returns a nonzero status, the poll of that mailserver will be aborted.

       Similarly, the 'postconnect' keyword similarly allows you to specify a shell command to be
       executed just after each time a mailserver connection is taken down.

       The 'forcecr' option  controls  whether  lines  terminated  by  LF  only  are  given  CRLF
       termination  before  forwarding.   Strictly  speaking  RFC821  requires this, but few MTAs
       enforce the requirement it so this option is normally off (only one such MTA, qmail, is in
       significant use at time of writing).

       The  'stripcr' option controls whether carriage returns are stripped out of retrieved mail
       before it is forwarded.  It is normally not necessary to set this, because it defaults  to
       'on'  (CR  stripping  enabled)  when  there  is  an  MDA  declared but 'off' (CR stripping
       disabled) when forwarding is via SMTP.  If 'stripcr' and 'forcecr' are both on,  'stripcr'
       will override.

       The  'pass8bits'  option  exists to cope with Microsoft mail programs that stupidly slap a
       "Content-Transfer-Encoding: 7bit" on everything.  With this option off (the  default)  and
       such  a  header  present,  fetchmail declares BODY=7BIT to an ESMTP-capable listener; this
       causes problems for messages actually using 8-bit ISO or KOI-8 character sets, which  will
       be  garbled  by  having  the  high bits of all characters stripped.  If 'pass8bits' is on,
       fetchmail is forced to declare  BODY=8BITMIME  to  any  ESMTP-capable  listener.   If  the
       listener  is  8-bit-clean  (as  all  the major ones now are) the right thing will probably
       result.

       The 'dropstatus' option controls whether nonempty Status and  X-Mozilla-Status  lines  are
       retained  in  fetched  mail (the default) or discarded.  Retaining them allows your MUA to
       see what messages (if any) were marked seen on the server.  On  the  other  hand,  it  can
       confuse  some  new-mail notifiers, which assume that anything with a Status line in it has
       been seen.  (Note: the  empty  Status  lines  inserted  by  some  buggy  POP  servers  are
       unconditionally discarded.)

       The  'dropdelivered'  option controls whether Delivered-To headers will be kept in fetched
       mail (the default) or discarded. These headers are added by Qmail and Postfix  mailservers
       in  order  to avoid mail loops but may get in your way if you try to "mirror" a mailserver
       within the same domain. Use with caution.

       The 'mimedecode' option controls whether MIME messages using the quoted-printable encoding
       are  automatically converted into pure 8-bit data. If you are delivering mail to an ESMTP-
       capable, 8-bit-clean listener (that includes all of the major MTAs  like  sendmail),  then
       this will automatically convert quoted-printable message headers and data into 8-bit data,
       making it easier to understand when reading mail. If your e-mail programs know how to deal
       with  MIME  messages,  then  this  option  is not needed.  The mimedecode option is off by
       default, because doing RFC2047 conversion on headers throws away character-set information
       and can lead to bad results if the encoding of the headers differs from the body encoding.

       The  'idle'  option  is  intended to be used with IMAP servers supporting the RFC2177 IDLE
       command extension, but does not strictly require it.  If  it  is  enabled,  and  fetchmail
       detects that IDLE is supported, an IDLE will be issued at the end of each poll.  This will
       tell the IMAP server to hold the connection open and notify the client when  new  mail  is
       available.   If  IDLE is not supported, fetchmail will simulate it by periodically issuing
       NOOP. If you need to poll a link frequently, IDLE can save bandwidth by eliminating TCP/IP
       connects and LOGIN/LOGOUT sequences. On the other hand, an IDLE connection will eat almost
       all of your fetchmail's time, because it will never drop the connection  and  allow  other
       polls  to  occur unless the server times out the IDLE.  It also doesn't work with multiple
       folders; only the first folder will ever be polled.

       The 'properties' option is an extension mechanism.  It takes a string argument,  which  is
       ignored  by  fetchmail  itself.   The  string  argument may be used to store configuration
       information for scripts which require it.  In particular,  the  output  of  '--configdump'
       option  will  make  properties  associated with a user entry readily available to a Python
       script.

   Miscellaneous Run Control Options
       The words 'here' and 'there' have useful English-like significance.  Normally  'user  eric
       is  esr'  would mean that mail for the remote user 'eric' is to be delivered to 'esr', but
       you can make this clearer by saying 'user eric there is esr here', or reverse it by saying
       'user esr here is eric there'

       Legal protocol identifiers for use with the 'protocol' keyword are:

           auto (or AUTO) (legacy, to be removed from future release)
           pop2 (or POP2) (legacy, to be removed from future release)
           pop3 (or POP3)
           sdps (or SDPS)
           imap (or IMAP)
           apop (or APOP)
           kpop (or KPOP)

       Legal authentication types are 'any', 'password', 'kerberos', 'kerberos_v4', 'kerberos_v5'
       and 'gssapi', 'cram-md5', 'otp', 'msn' (only for POP3), 'ntlm',  'ssh',  'external'  (only
       IMAP).   The 'password' type specifies authentication by normal transmission of a password
       (the password may be plain text or subject to protocol-specific  encryption  as  in  CRAM-
       MD5);  'kerberos'  tells  fetchmail  to  try to get a Kerberos ticket at the start of each
       query instead, and send an arbitrary string as the password; and 'gssapi' tells  fetchmail
       to use GSSAPI authentication.  See the description of the 'auth' keyword for more.

       Specifying  'kpop'  sets  POP3  protocol  over  port 1109 with Kerberos V4 authentication.
       These defaults may be overridden by later options.

       There are some global option statements: 'set logfile' followed by a string sets the  same
       global  specified  by --logfile.  A command-line --logfile option will override this. Note
       that --logfile is only effective if fetchmail detaches itself from the  terminal  and  the
       logfile  already  exists  before fetchmail is run, and it overrides --syslog in this case.
       Also, 'set daemon' sets the poll interval as --daemon does.  This can be overridden  by  a
       command-line  --daemon  option;  in  particular --daemon 0 can be used to force foreground
       operation. The 'set postmaster'  statement  sets  the  address  to  which  multidrop  mail
       defaults  if  there  are  no  local  matches.  Finally, 'set syslog' sends log messages to
       syslogd(8).

DEBUGGING FETCHMAIL

   Fetchmail crashing
       There are various ways in that fetchmail may "crash", i. e. stop  operation  suddenly  and
       unexpectedly.  A  "crash"  usually  refers to an error condition that the software did not
       handle by itself. A well-known failure mode is the "segmentation fault" or "signal 11"  or
       "SIGSEGV"  or  just  "segfault"  for short. These can be caused by hardware or by software
       problems. Software-induced segfaults can usually be reproduced  easily  and  in  the  same
       place,  whereas  hardware-induced  segfaults  can  go away if the computer is rebooted, or
       powered off for a few hours, and can happen in  random  locations  even  if  you  use  the
       software the same way.

       For  solving  hardware-induced  segfaults, find the faulty component and repair or replace
       it.  The Sig11 FAQ ⟨http://www.bitwizard.nl/sig11/⟩ may help you with details.

       For solving software-induced segfaults, the developers may need a "stack backtrace".

   Enabling fetchmail core dumps
       By default, fetchmail suppresses core dumps as these might  contain  passwords  and  other
       sensitive information. For debugging fetchmail crashes, obtaining a "stack backtrace" from
       a core dump is often the quickest way to solve the problem, and when posting your  problem
       on a mailing list, the developers may ask you for a "backtrace".

       1.  To  get useful backtraces, fetchmail needs to be installed without getting stripped of
       its compilation symbols.  Unfortunately, most  binary  packages  that  are  installed  are
       stripped,  and  core files from symbol-stripped programs are worthless. So you may need to
       recompile fetchmail. On many systems, you can type

               file `which fetchmail`

       to find out if fetchmail was symbol-stripped  or  not.  If  yours  was  unstripped,  fine,
       proceed,  if  it  was  stripped,  you  need to recompile the source code first. You do not
       usually need to install fetchmail in order to debug it.

       2. The shell environment that starts fetchmail needs to enable core dumps. The key is  the
       "maximum  core  (file)  size"  that can usually be configured with a tool named "limit" or
       "ulimit". See the documentation for your shell for details. In  the  popular  bash  shell,
       "ulimit -Sc unlimited" will allow the core dump.

       3.  You  need  to tell fetchmail, too, to allow core dumps. To do this, run fetchmail with
       the -d0 -v options.  It is often easier to also add --nosyslog -N as well.

       Finally, you need to reproduce the crash. You can just start fetchmail from the  directory
       where  you compiled it by typing ./fetchmail, so the complete command line will start with
       ./fetchmail -Nvd0 --nosyslog and perhaps list your other options.

       After the crash, run your debugger to obtain the core dump.  The debugger  will  often  be
       GNU  GDB, you can then type (adjust paths as necessary) gdb ./fetchmail fetchmail.core and
       then, after GDB has started up and read all its  files,  type  backtrace  full,  save  the
       output (copy & paste will do, the backtrace will be read by a human) and then type quit to
       leave gdb.  Note: on some systems, the core files have different names, they might contain
       a  number instead of the program name, or number and name, but it will usually have "core"
       as part of their name.

INTERACTION WITH RFC 822

       When trying to determine the originating address of a  message,  fetchmail  looks  through
       headers in the following order:

               Return-Path:
               Resent-Sender: (ignored if it doesn't contain an @ or !)
               Sender: (ignored if it doesn't contain an @ or !)
               Resent-From:
               From:
               Reply-To:
               Apparently-From:

       The  originating  address  is  used  for  logging,  and  to set the MAIL FROM address when
       forwarding to SMTP.  This order is intended to cope gracefully with receiving mailing list
       messages  in  multidrop  mode.  The  intent  is that if a local address doesn't exist, the
       bounce message won't be returned blindly to the author or to the list itself,  but  rather
       to the list manager (which is less annoying).

       In  multidrop  mode,  destination headers are processed as follows: First, fetchmail looks
       for the header specified by  the  'envelope'  option  in  order  to  determine  the  local
       recipient  address. If the mail is addressed to more than one recipient, the Received line
       won't contain any information regarding recipient addresses.

       Then fetchmail looks for the Resent-To:,  Resent-Cc:,  and  Resent-Bcc:  lines.   If  they
       exist,   they  should  contain  the  final  recipients  and  have  precedence  over  their
       To:/Cc:/Bcc: counterparts.  If the Resent-* lines don't exist,  the  To:,  Cc:,  Bcc:  and
       Apparently-To:  lines are looked for. (The presence of a Resent-To: is taken to imply that
       the person referred by the To: address has already  received  the  original  copy  of  the
       mail.)

CONFIGURATION EXAMPLES

       Note  that  although there are password declarations in a good many of the examples below,
       this is mainly for illustrative purposes.  We recommend stashing account/password pairs in
       your  $HOME/.netrc  file,  where  they can be used not just by fetchmail but by ftp(1) and
       other programs.

       The basic format is:

              poll SERVERNAME protocol PROTOCOL username NAME password PASSWORD

       Example:

              poll pop.provider.net protocol pop3 username "jsmith" password "secret1"

       Or, using some abbreviations:

              poll pop.provider.net proto pop3 user "jsmith" password "secret1"

       Multiple servers may be listed:

              poll pop.provider.net proto pop3 user "jsmith" pass "secret1"
              poll other.provider.net proto pop2 user "John.Smith" pass "My^Hat"

       Here's the same version with more whitespace and some noise words:

              poll pop.provider.net proto pop3
                   user "jsmith", with password secret1, is "jsmith" here;
              poll other.provider.net proto pop2:
                   user "John.Smith", with password "My^Hat", is "John.Smith" here;

       If you need to include whitespace in a parameter string or start the latter with a number,
       enclose the string in double quotes.  Thus:

              poll mail.provider.net with proto pop3:
                   user "jsmith" there has password "4u but u can't krak this"
                   is jws here and wants mda "/bin/mail"

       You  may  have  an  initial server description headed by the keyword 'defaults' instead of
       'poll' followed by a name.  Such a record is interpreted as defaults for  all  queries  to
       use. It may be overwritten by individual server descriptions.  So, you could write:

              defaults proto pop3
                   user "jsmith"
              poll pop.provider.net
                   pass "secret1"
              poll mail.provider.net
                   user "jjsmith" there has password "secret2"

       It's  possible  to  specify more than one user per server.  The 'user' keyword leads off a
       user description, and every user specification in a  multi-user  entry  must  include  it.
       Here's an example:

              poll pop.provider.net proto pop3 port 3111
                   user "jsmith" with pass "secret1" is "smith" here
                   user jones with pass "secret2" is "jjones" here keep

       This associates the local username 'smith' with the pop.provider.net username 'jsmith' and
       the local username 'jjones' with the pop.provider.net username 'jones'.  Mail for  'jones'
       is kept on the server after download.

       Here's what a simple retrieval configuration for a multidrop mailbox looks like:

              poll pop.provider.net:
                   user maildrop with pass secret1 to golux 'hurkle'='happy' snark here

       This  says  that  the  mailbox of account 'maildrop' on the server is a multidrop box, and
       that messages in it should be parsed for the server  user  names  'golux',  'hurkle',  and
       'snark'.   It  further specifies that 'golux' and 'snark' have the same name on the client
       as on the server, but mail for server user 'hurkle' should be  delivered  to  client  user
       'happy'.

       Note  that  fetchmail,  until version 6.3.4, did NOT allow full user@domain specifications
       here,  these  would  never  match.   Fetchmail  6.3.5  and   newer   support   user@domain
       specifications on the left-hand side of a user mapping.

       Here's an example of another kind of multidrop connection:

              poll pop.provider.net localdomains loonytoons.org toons.org
                   envelope X-Envelope-To
                   user maildrop with pass secret1 to * here

       This  also  says  that the mailbox of account 'maildrop' on the server is a multidrop box.
       It tells fetchmail that any address in the loonytoons.org or toons.org domains  (including
       sub-domain  addresses  like  'joe@daffy.loonytoons.org')  should  be passed through to the
       local SMTP listener without modification.  Be careful of mail loops if you do this!

       Here's an example configuration using ssh and the plugin option.   The  queries  are  made
       directly  on  the  stdin  and  stdout  of  imapd  via  ssh.  Note that in this setup, IMAP
       authentication can be skipped.

              poll mailhost.net with proto imap:
                   plugin "ssh %h /usr/sbin/imapd" auth ssh;
                   user esr is esr here

THE USE AND ABUSE OF MULTIDROP MAILBOXES

       Use the multiple-local-recipients feature with caution --  it  can  bite.   All  multidrop
       features are ineffective in ETRN and ODMR modes.

       Also,  note  that  in  multidrop  mode duplicate mails are suppressed.  A piece of mail is
       considered duplicate if it has the same message-ID as the  message  immediately  preceding
       and  more  than  one  addressee.   Such runs of messages may be generated when copies of a
       message addressed to multiple users are delivered to a multidrop box.

   Header vs. Envelope addresses
       The fundamental problem is that by having your mailserver toss several peoples' mail in  a
       single maildrop box, you may have thrown away potentially vital information about who each
       piece of mail was actually addressed to (the 'envelope address', as opposed to the  header
       addresses  in  the  RFC822 To/Cc headers - the Bcc is not available at the receiving end).
       This 'envelope address' is the address you need in order to reroute mail properly.

       Sometimes fetchmail can deduce the envelope address.  If the mailserver  MTA  is  sendmail
       and  the  item of mail had just one recipient, the MTA will have written a 'by/for' clause
       that gives the envelope addressee into its Received header. But this doesn't work reliably
       for  other MTAs, nor if there is more than one recipient.  By default, fetchmail looks for
       envelope addresses in these lines; you can restore this  default  with  -E  "Received"  or
       'envelope Received'.

       As  a  better alternative, some SMTP listeners and/or mail servers insert a header in each
       message containing a copy of the envelope addresses.  This  header  (when  it  exists)  is
       often  'X-Original-To',  'Delivered-To'  or 'X-Envelope-To'.  Fetchmail's assumption about
       this can be changed with the -E or 'envelope'  option.   Note  that  writing  an  envelope
       header  of  this kind exposes the names of recipients (including blind-copy recipients) to
       all receivers of the messages, so the upstream must store one  copy  of  the  message  per
       recipient to avoid becoming a privacy problem.

       Postfix,  since  version 2.0, writes an X-Original-To: header which contains a copy of the
       envelope as it was received.

       Qmail and Postfix generally write a 'Delivered-To' header upon delivering the  message  to
       the  mail spool and use it to avoid mail loops.  Qmail virtual domains however will prefix
       the user name with a string that normally matches the user's domain. To remove this prefix
       you can use the -Q or 'qvirtual' option.

       Sometimes,  unfortunately,  neither  of  these  methods works.  That is the point when you
       should contact your ISP and ask them to provide such an envelope header,  and  you  should
       not  use multidrop in this situation.  When they all fail, fetchmail must fall back on the
       contents of To/Cc headers (Bcc headers are not available - see below) to try to  determine
       recipient  addressees  --  and these are unreliable.  In particular, mailing-list software
       often ships mail with only the list broadcast address in the To header.

       Note that a future version of fetchmail may remove To/Cc parsing!

       When fetchmail cannot deduce a recipient address that is local, and the intended recipient
       address was anyone other than fetchmail's invoking user, mail will get lost.  This is what
       makes the multidrop feature risky without proper envelope information.

       A related problem is that when you blind-copy a  mail  message,  the  Bcc  information  is
       carried  only  as  envelope  address  (it's  removed  from the headers by the sending mail
       server, so fetchmail can see it only if there is an X-Envelope-To header).   Thus,  blind-
       copying  to someone who gets mail over a fetchmail multidrop link will fail unless the the
       mailserver host routinely writes X-Envelope-To or an equivalent header  into  messages  in
       your maildrop.

       In  conclusion,  mailing  lists and Bcc'd mail can only work if the server you're fetching
       from

       (1)    stores one copy of the message per recipient in your domain and

       (2)    records the envelope information in a special header (X-Original-To,  Delivered-To,
              X-Envelope-To).

   Good Ways To Use Multidrop Mailboxes
       Multiple  local  names  can be used to administer a mailing list from the client side of a
       fetchmail collection.  Suppose your name is 'esr', and you want to both pick up  your  own
       mail  and  maintain  a mailing list called (say) "fetchmail-friends", and you want to keep
       the alias list on your client machine.

       On your server, you can alias 'fetchmail-friends' to 'esr'; then,  in  your  .fetchmailrc,
       declare 'to esr fetchmail-friends here'.  Then, when mail including 'fetchmail-friends' as
       a local address gets fetched, the list name will be appended to  the  list  of  recipients
       your  SMTP  listener sees.  Therefore it will undergo alias expansion locally.  Be sure to
       include 'esr' in the local alias expansion of fetchmail-friends, or you'll never see  mail
       sent  only  to  the  list.   Also  be  sure that your listener has the "me-too" option set
       (sendmail's -oXm command-line option or OXm declaration) so your name isn't  removed  from
       alias expansions in messages you send.

       This  trick is not without its problems, however.  You'll begin to see this when a message
       comes in that is addressed only to a mailing list you do not  have  declared  as  a  local
       name.   Each  such message will feature an 'X-Fetchmail-Warning' header which is generated
       because fetchmail cannot find a  valid  local  name  in  the  recipient  addresses.   Such
       messages  default  (as  was  described  above)  to  being  sent  to the local user running
       fetchmail, but the program has no way to know that that's actually the right thing.

   Bad Ways To Abuse Multidrop Mailboxes
       Multidrop mailboxes and fetchmail serving multiple users in daemon mode do not  mix.   The
       problem,  again,  is  mail from mailing lists, which typically does not have an individual
       recipient address on it.   Unless fetchmail can deduce an envelope address, such mail will
       only  go  to  the account running fetchmail (probably root).  Also, blind-copied users are
       very likely never to see their mail at all.

       If you're tempted to use fetchmail to retrieve mail for multiple users from a single  mail
       drop via POP or IMAP, think again (and reread the section on header and envelope addresses
       above).  It would be smarter to just let the mail sit in the mailserver's  queue  and  use
       fetchmail's  ETRN  or ODMR modes to trigger SMTP sends periodically (of course, this means
       you have to poll more frequently than the  mailserver's  expiry  period).   If  you  can't
       arrange this, try setting up a UUCP feed.

       If you absolutely must use multidrop for this purpose, make sure your mailserver writes an
       envelope-address header that fetchmail can see.  Otherwise you will lose mail and it  will
       come back to haunt you.

   Speeding Up Multidrop Checking
       Normally,  when  multiple  users  are  declared  fetchmail extracts recipient addresses as
       described above and checks each host part with  DNS  to  see  if  it's  an  alias  of  the
       mailserver.   If so, the name mappings described in the "to ... here" declaration are done
       and the mail locally delivered.

       This is a convenient but also slow method.  To speed it up, pre-declare mailserver aliases
       with  'aka';  these  are  checked before DNS lookups are done.  If you're certain your aka
       list contains all DNS aliases of the mailserver (and all MX names pointing at  it  -  note
       this  may  change  in  a  future version) you can declare 'no dns' to suppress DNS lookups
       entirely and only match against the aka list.

SOCKS

       Support for socks4/5 is a compile time configuration option. Once compiled  in,  fetchmail
       will  always  use  the socks libraries and configuration on your system, there are no run-
       time switches in fetchmail - but you can still configure  SOCKS:  you  can  specify  which
       SOCKS configuration file is used in the SOCKS_CONF environment variable.

       For  instance,  if  you  wanted  to  bypass  the SOCKS proxy altogether and have fetchmail
       connect directly, you could just pass SOCKS_CONF=/dev/null in the environment, for example
       (add your usual command line options - if any - to the end of this line):

       env SOCKS_CONF=/dev/null fetchmail

EXIT CODES

       To  facilitate  the  use of fetchmail in shell scripts, an exit status code is returned to
       give an indication of what occurred during a given connection.

       The exit codes returned by fetchmail are as follows:

       0      One or more messages  were  successfully  retrieved  (or,  if  the  -c  option  was
              selected, were found waiting but not retrieved).

       1      There  was  no mail awaiting retrieval.  (There may have been old mail still on the
              server but not selected for retrieval.) If you do not want "no mail" to be an error
              condition (for instance, for cron jobs), use a POSIX-compliant shell and add

              || [ $? -eq 1 ]

              to the end of the fetchmail command line, note that this leaves 0 untouched, maps 1
              to 0, and maps all other codes to 1. See also item #C8 in the FAQ.

       2      An error was encountered when attempting to open a socket to retrieve mail.  If you
              don't  know  what  a  socket  is,  don't  worry  about  it -- just treat this as an
              'unrecoverable error'.  This error can also be because a protocol  fetchmail  wants
              to use is not listed in /etc/services.

       3      The  user  authentication  step  failed.   This  usually  means that a bad user-id,
              password, or APOP id was specified.  Or it may mean that you tried to run fetchmail
              under circumstances where it did not have standard input attached to a terminal and
              could not prompt for a missing password.

       4      Some sort of fatal protocol error was detected.

       5      There was a syntax error in the arguments to fetchmail, or a pre-  or  post-connect
              command failed.

       6      The run control file had bad permissions.

       7      There  was  an  error condition reported by the server.  Can also fire if fetchmail
              timed out while waiting for the server.

       8      Client-side exclusion error.  This means fetchmail either  found  another  copy  of
              itself  already running, or failed in such a way that it isn't sure whether another
              copy is running.

       9      The user authentication step failed because the server responded "lock busy".   Try
              again  after  a  brief pause!  This error is not implemented for all protocols, nor
              for all servers.  If not implemented for your server, "3" will be returned instead,
              see  above.   May  be  returned  when  talking to qpopper or other servers that can
              respond with "lock busy" or some similar text containing the word "lock".

       10     The fetchmail run failed while trying to do an SMTP port open or transaction.

       11     Fatal DNS error.  Fetchmail encountered an error while performing a DNS  lookup  at
              startup and could not proceed.

       12     BSMTP batch file could not be opened.

       13     Poll terminated by a fetch limit (see the --fetchlimit option).

       14     Server busy indication.

       23     Internal error.  You should see a message on standard error with details.

       24 - 26, 28, 29
              These are internal codes and should not appear externally.

       When  fetchmail  queries  more than one host, return status is 0 if any query successfully
       retrieved mail. Otherwise the returned error status is that of the last host queried.

FILES

       ~/.fetchmailrc
            default run control file

       ~/.fetchids
            default location of file recording last message UIDs seen per host.

       ~/.fetchmail.pid
            lock file to help prevent concurrent runs (non-root mode).

       ~/.netrc
            your FTP run control file, which (if present) will be searched  for  passwords  as  a
            last resort before prompting for one interactively.

       /var/run/fetchmail.pid
            lock file to help prevent concurrent runs (root mode, Linux systems).

       /etc/fetchmail.pid
            lock file to help prevent concurrent runs (root mode, systems without /var/run).

ENVIRONMENT

       FETCHMAILHOME
              If  this  environment  variable  is  set  to  a  valid and existing directory name,
              fetchmail will read $FETCHMAILHOME/fetchmailrc (the dot is missing in  this  case),
              $FETCHMAILHOME/.fetchids  and  $FETCHMAILHOME/.fetchmail.pid  rather  than from the
              user's home directory.  The .netrc file is always looked for in  the  the  invoking
              user's home directory regardless of FETCHMAILHOME's setting.

       FETCHMAILUSER
              If  this  environment  variable  is set, it is used as the name of the calling user
              (default local name) for purposes such as mailing error notifications.   Otherwise,
              if either the LOGNAME or USER variable is correctly set (e.g. the corresponding UID
              matches the session user ID) then that name is used  as  the  default  local  name.
              Otherwise  getpwuid(3) must be able to retrieve a password entry for the session ID
              (this elaborate logic is designed to handle the case of multiple names  per  userid
              gracefully).

       FETCHMAIL_DISABLE_CBC_IV_COUNTERMEASURE
              (since  v6.3.22): If this environment variable is set and not empty, fetchmail will
              disable  a  countermeasure   against   an   SSL   CBC   IV   attack   (by   setting
              SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS).  This is a security risk, but may be necessary
              for connecting to certain non-standards-conforming servers.  See  fetchmail's  NEWS
              file and fetchmail-SA-2012-01.txt for details.  Earlier fetchmail versions (v6.3.21
              and older) used to disable this countermeasure, but v6.3.22 no longer does that  as
              a safety precaution.

       FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS
              (since  v6.3.17): If this environment variable is set and not empty, fetchmail will
              always load  the  default  X.509  trusted  certificate  locations  for  SSL/TLS  CA
              certificates,  even  if  --sslcertfile  and  --sslcertpath  are  given.  The latter
              locations take precedence over the system default locations.   This  is  useful  in
              case  there  are  broken certificates in the system directories and the user has no
              administrator privileges to remedy the problem.

       HOME_ETC
              If the HOME_ETC variable is set, fetchmail will read $HOME_ETC/.fetchmailrc instead
              of ~/.fetchmailrc.

              If HOME_ETC and FETCHMAILHOME are both set, HOME_ETC will be ignored.

       SOCKS_CONF
              (only  if  SOCKS support is compiled in) this variable is used by the socks library
              to find out which configuration file it should  read.  Set  this  to  /dev/null  to
              bypass the SOCKS proxy.

SIGNALS

       If  a  fetchmail  daemon  is running as root, SIGUSR1 wakes it up from its sleep phase and
       forces a poll of all non-skipped servers. For compatibility reasons, SIGHUP  can  also  be
       used in 6.3.X but may not be available in future fetchmail versions.

       If  fetchmail  is  running  in daemon mode as non-root, use SIGUSR1 to wake it (this is so
       SIGHUP due to logout can retain the default action of killing it).

       Running fetchmail in foreground while a background fetchmail is running will do  whichever
       of these is appropriate to wake it up.

BUGS, LIMITATIONS, AND KNOWN PROBLEMS

       Please  check  the  NEWS  file  that shipped with fetchmail for more known bugs than those
       listed here.

       Fetchmail cannot handle user names that contain blanks after a "@" character, for instance
       "demonstr@ti  on".  These  are  rather  uncommon and only hurt when using UID-based --keep
       setups, so the 6.3.X versions of fetchmail won't be fixed.

       Fetchmail cannot handle configurations where you have multiple accounts that use the  same
       server name and the same login. Any user@server combination must be unique.

       The  assumptions  that the DNS and in particular the checkalias options make are not often
       sustainable. For instance, it has become uncommon for an MX server to be a  POP3  or  IMAP
       server at the same time. Therefore the MX lookups may go away in a future release.

       The mda and plugin options interact badly.  In order to collect error status from the MDA,
       fetchmail has to change its normal signal handling so that dead plugin processes don't get
       reaped  until  the  end of the poll cycle.  This can cause resource starvation if too many
       zombies accumulate.  So either don't deliver to a MDA using plugins or risk being  overrun
       by an army of undead.

       The  --interface  option  does  not support IPv6 and it is doubtful if it ever will, since
       there is no portable way to query interface IPv6 addresses.

       The RFC822 address parser used in multidrop mode  chokes  on  some  @-addresses  that  are
       technically  legal  but bizarre.  Strange uses of quoting and embedded comments are likely
       to confuse it.

       In a message with multiple envelope headers, only the last one processed will  be  visible
       to fetchmail.

       Use  of  some of these protocols requires that the program send unencrypted passwords over
       the TCP/IP connection to the mailserver.  This creates a  risk  that  name/password  pairs
       might  be snaffled with a packet sniffer or more sophisticated monitoring software.  Under
       Linux and FreeBSD, the --interface option can be used to restrict polling to  availability
       of a specific interface device with a specific local or remote IP address, but snooping is
       still possible if (a) either host has a network device that can be opened  in  promiscuous
       mode,  or  (b) the intervening network link can be tapped.  We recommend the use of ssh(1)
       tunnelling to not only shroud your passwords but encrypt the entire conversation.

       Use of the %F or %T escapes in an mda option could open a security hole, because they pass
       text  manipulable  by  an  attacker  to  a  shell command.  Potential shell characters are
       replaced by '_' before execution.  The hole is further reduced by the fact that  fetchmail
       temporarily  discards  any suid privileges it may have while running the MDA.  For maximum
       safety, however, don't use an mda command containing %F or %T when fetchmail is  run  from
       the root account itself.

       Fetchmail's  method  of  sending  bounces  due to errors or spam-blocking and spam bounces
       requires that port 25 of localhost be available for sending mail via SMTP.

       If you modify ~/.fetchmailrc while a background instance is running and break the  syntax,
       the background instance will die silently.  Unfortunately, it can't die noisily because we
       don't yet know whether syslog should be enabled.  On some systems, fetchmail dies  quietly
       even  if  there is no syntax error; this seems to have something to do with buggy terminal
       ioctl code in the kernel.

       The -f - option (reading a configuration from  stdin)  is  incompatible  with  the  plugin
       option.

       The 'principal' option only handles Kerberos IV, not V.

       Interactively  entered  passwords are truncated after 63 characters. If you really need to
       use a longer password, you will have to use a configuration file.

       A backslash as the last character of a configuration file will  be  flagged  as  a  syntax
       error rather than ignored.

       The BSMTP error handling is virtually nonexistent and may leave broken messages behind.

       Send   comments,   bug   reports,  gripes,  and  the  like  to  the  fetchmail-devel  list
       ⟨fetchmail-devel@lists.berlios.de⟩

       An HTML FAQ ⟨http://fetchmail.berlios.de/fetchmail-FAQ.html⟩ is available at the fetchmail
       home page, it should also accompany your installation.

AUTHOR

       Fetchmail  is  currently  maintained by Matthias Andree and Rob Funk with major assistance
       from Sunil Shetye (for code) and Rob MacGregor (for the mailing lists).

       Most of the code is from Eric S. Raymond ⟨esr@snark.thyrsus.com⟩ .  Too many other  people
       to name here have contributed code and patches.

       This program is descended from and replaces popclient, by Carl Harris ⟨ceharris@mal.com⟩ ;
       the internals have become quite different, but some of its interface  design  is  directly
       traceable to that ancestral program.

       This  manual  page  has  been  improved  by Matthias Andree, R. Hannes Beinert, and Héctor
       García.

SEE ALSO

       README, README.SSL, README.SSL-SERVER, The Fetchmail FAQ ⟨http://www.fetchmail.info/
       fetchmail-FAQ.html⟩, mutt(1), elm(1), mail(1), sendmail(8), popd(8), imapd(8), netrc(5).

       The fetchmail home page.  ⟨http://fetchmail.berlios.de/⟩

       The maildrop home page.  ⟨http://www.courier-mta.org/maildrop/

APPLICABLE STANDARDS

       Note  that  this  list  is  just  a collection of references and not a statement as to the
       actual protocol conformance or requirements in fetchmail.

       SMTP/ESMTP:
            RFC 821, RFC 2821, RFC 1869, RFC 1652, RFC 1870, RFC 1983, RFC 1985, RFC 2554.

       mail:
            RFC 822, RFC 2822, RFC 1123, RFC 1892, RFC 1894.

       POP2:
            RFC 937

       POP3:
            RFC 1081, RFC 1225, RFC 1460, RFC 1725, RFC 1734, RFC 1939, RFC 1957, RFC  2195,  RFC
            2449.

       APOP:
            RFC 1939.

       RPOP:
            RFC 1081, RFC 1225.

       IMAP2/IMAP2BIS:
            RFC 1176, RFC 1732.

       IMAP4/IMAP4rev1:
            RFC 1730, RFC 1731, RFC 1732, RFC 2060, RFC 2061, RFC 2195, RFC 2177, RFC 2683.

       ETRN:
            RFC 1985.

       ODMR/ATRN:
            RFC 2645.

       OTP: RFC 1938.

       LMTP:
            RFC 2033.

       GSSAPI:
            RFC 1508, RFC 1734, Generic Security Service Application Program Interface
            (GSSAPI)/Kerberos/Simple Authentication and Security Layer (SASL) Service Names
            ⟨http://www.iana.org/assignments/gssapi-service-names/⟩.

       TLS: RFC 2595.