Provided by: fetchmail_6.3.21-2_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. Default to match historic fetchmail
              documentation, to 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.  Connect to the
              server using the specified base protocol over a connection  secured  by  SSL.  This
              option  defeats opportunistic starttls negotiation. It is highly recommended to use
              --sslproto 'SSL3' --sslcertck to validate the certificates presented by the  server
              and  defeat  the  obsolete  SSLv2 negotiation. More information is available in the
              README.SSL file that ships with fetchmail.

              Note that fetchmail may still try to negotiate SSL through starttls  even  if  this
              option  is  omitted.  You  can use the --sslproto option to defeat this behavior or
              tell fetchmail to negotiate a particular SSL protocol.

              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 <name>
              (Keyword: sslproto)
              Forces an SSL/TLS protocol. Possible values are  '',  'SSL23'  (note  however  that
              fetchmail,  since v6.3.20, prohibits negotiation of SSLv2 -- it has been deprecated
              for 15 years and is insecure), 'SSL3', and 'TLS1'.  The default behaviour  if  this
              option  is  unset  is:  for connections without --ssl, use 'TLS1' so that fetchmail
              will opportunistically try STARTTLS negotiation with TLS1. You can  configure  this
              option  explicitly  if  the  default handshake (TLS1 if --ssl is not used) does not
              work for your server.

              Use this option with 'TLS1' value to enforce a STARTTLS connection. In  this  mode,
              it  is highly recommended to also use --sslcertck (see below).  Note that this will
              then cause fetchmail v6.3.19 to force  STARTTLS  negotiation  even  if  it  is  not
              advertised by the server.

              To  defeat  opportunistic  TLSv1 negotiation when the server advertises STARTTLS or
              STLS, and use a cleartext connection use ''.  This option, even if the argument  is
              the  empty string, will also suppress the diagnostic 'SERVER: opportunistic upgrade
              to TLS.' message in verbose mode. The  default  is  to  try  appropriate  protocols
              depending on context.

       --sslcertck
              (Keyword: sslcertck)
              Causes  fetchmail  to  strictly check the server certificate against 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),  the  SSL  connection  will  fail,  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 default format OpenSSL uses, and the one 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)
       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  with  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 --ssl option.  You can also do
       this using the "ssl" user option in the .fetchmailrc file. With  SSL  encryption  enabled,
       queries  are  initiated  over  a  connection  after  negotiating  an  SSL session, and the
       connection fails if SSL cannot be negotiated.  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.  The
       --sslproto 'SSL3' option should be used to select the SSLv3 protocol (default if unset: v2
       or v3).  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 "TLS1". 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.

       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 (though perhaps it shouldn't).

       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  on  the
       following SMTP/ESMTP error responses

       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 trigger bounce mail back to the originator. 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.
       set idfile          -i           Name  of  the  file  to  store UID
                                        lists in.
       set    syslog                    Do    error    logging     through
                                        syslog(3).
       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_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 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.

       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.