xenial (1) fetchmail.1.gz

Provided by: fetchmail_6.3.26-2_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.   This  option  is  on  by  default  to  match  historic  fetchmail
              documentation, and will be changed to hard bounce mode in the next fetchmail release.

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

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

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

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

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

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

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

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

              POP3   Post Office Protocol 3

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

              RPOP   Use POP3 with RPOP authentication.

              KPOP   Use POP3 with Kerberos V4 authentication on port 1109.

              SDPS   Use POP3 with Demon Internet's SDPS extensions.

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

              ETRN   Use the ESMTP ETRN option.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              Also see --sslcert above.

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

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

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

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

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

              'SSL23'
                     see 'auto'.

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

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

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

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

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

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

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

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

              Unrecognized parameters
                     are treated the same as 'auto'.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              For details, see x509(1ssl).

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

USER AUTHENTICATION AND ENCRYPTION

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

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

              fetchmail -u jsmith mailgrunt

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

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

              machine hermes.example.org
              login joe
              password topsecret

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

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

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

POP3 VARIANTS

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

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

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

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

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

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

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

ALTERNATE AUTHENTICATION FORMS

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

DAEMON MODE

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

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

       Example: simply invoking

              fetchmail -d 900

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

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

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

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

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

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

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

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

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

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

ADMINISTRATIVE OPTIONS

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

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

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

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

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

RETRIEVAL FAILURE MODES

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

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

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

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

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

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

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

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

SPAM FILTERING

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

       Newer versions of sendmail return an error code of 571.

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

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

       The postfix MTA runs 554 as an antispam response.

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

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

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

       By default, the list of antispam responses is empty.

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

SMTP/ESMTP ERROR HANDLING

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

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

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

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

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

THE RUN CONTROL FILE

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

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

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

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

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

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

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

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

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

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

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

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

       Here are the legal global options:

       Keyword             Opt   Mode   Function
       ────────────────────────────────────────────────────────────────────
       set daemon          -d           Set  a background poll interval in
                                        seconds.

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

       Here are the legal server options:

       Keyword          Opt   Mode   Function
       ─────────────────────────────────────────────────────────────────
       via                           Specify  DNS  name  of mailserver,
                                     overriding poll name
       proto[col]       -p           Specify       protocol       (case
                                     insensitive):  POP2,  POP3,  IMAP,
                                     APOP, KPOP
       local[domains]         m      Specify domain(s) to  be  regarded
                                     as local
       port                          Specify    TCP/IP   service   port
                                     (obsolete, use 'service' instead).
       service          -P           Specify service  name  (a  numeric
                                     value    is   also   allowed   and
                                     considered a TCP/IP port number).
       auth[enticate]                Set authentication  type  (default
                                     'any')
       timeout          -t           Server   inactivity   timeout   in
                                     seconds (default 300)
       envelope         -E    m      Specify  envelope-address   header
                                     name
       no envelope            m      Disable   looking   for   envelope
                                     address
       qvirtual         -Q    m      Qmail  virtual  domain  prefix  to
                                     remove from user name

       aka                    m      Specify  alternate  DNS  names  of
                                     mailserver
       interface        -I           specify IP interface(s) that  must
                                     be  up  for  server  poll  to take
                                     place
       monitor          -M           Specify IP address to monitor  for
                                     activity
       plugin                        Specify  command  through which to
                                     make server connections.
       plugout                       Specify command through  which  to
                                     make listener connections.
       dns                    m      Enable  DNS  lookup  for multidrop
                                     (default)
       no dns                 m      Disable DNS lookup for multidrop
       checkalias             m      Do comparison by  IP  address  for
                                     multidrop
       no checkalias          m      Do    comparison   by   name   for
                                     multidrop (default)
       uidl             -U           Force  POP3  to  use   client-side
                                     UIDLs (recommended)
       no uidl                       Turn  off  POP3 use of client-side
                                     UIDLs (default)
       interval                      Only check this site every N  poll
                                     cycles; N is a numeric argument.
       tracepolls                    Add  poll  tracing  information to
                                     the Received header
       principal                     Set   Kerberos   principal   (only
                                     useful with IMAP and kerberos)
       esmtpname                     Set      name      for     RFC2554
                                     authentication   to   the    ESMTP
                                     server.
       esmtppassword                 Set     password    for    RFC2554
                                     authentication   to   the    ESMTP
                                     server.
       bad-header                    How  to  treat messages with a bad
                                     header. Can be reject (default) or
                                     accept.

       Here are the legal user descriptions and options:

       Keyword            Opt   Mode   Function
       ───────────────────────────────────────────────────────────────────
       user[name]         -u           This  is  the user description and
                                       must  come  first   after   server
                                       description   and  after  possible
                                       server options,  and  before  user
                                       options.
                                       It sets the remote user name if by
                                       itself or followed by 'there',  or
                                       the local user name if followed by
                                       'here'.
       is                              Connect  local  and  remote   user
                                       names
       to                              Connect   local  and  remote  user
                                       names
       pass[word]                      Specify remote account password
       ssl                             Connect   to   server   over   the
                                       specified  base protocol using SSL
                                       encryption
       sslcert                         Specify  file  for   client   side
                                       public SSL certificate
       sslcertfile                     Specify   file   with  trusted  CA
                                       certificates
       sslcertpath                     Specify c_rehash-ed directory with
                                       trusted CA certificates.
       sslkey                          Specify   file   for  client  side
                                       private SSL key
       sslproto                        Force ssl protocol for connection
       folder             -r           Specify remote folder to query
       smtphost           -S           Specify smtp host(s) to forward to

       fetchdomains             m      Specify  domains  for  which  mail
                                       should be fetched
       smtpaddress        -D           Specify  the  domain  to be put in
                                       RCPT TO lines
       smtpname                        Specify the user and domain to  be
                                       put in RCPT TO lines
       antispam           -Z           Specify   what  SMTP  returns  are
                                       interpreted as spam-policy blocks
       mda                -m           Specify MDA for local delivery
       bsmtp              -o           Specify BSMTP batch file to append
                                       to
       preconnect                      Command to be executed before each
                                       connection
       postconnect                     Command to be executed after  each
                                       connection
       keep               -k           Don't  delete  seen  messages from
                                       server   (for   POP3,   uidl    is
                                       recommended)
       flush              -F           Flush  all  seen  messages  before
                                       querying (DANGEROUS)
       limitflush                      Flush   all   oversized   messages
                                       before querying
       fetchall           -a           Fetch all messages whether seen or
                                       not
       rewrite                         Rewrite destination addresses  for
                                       reply (default)
       stripcr                         Strip  carriage  returns from ends
                                       of lines
       forcecr                         Force carriage returns at ends  of
                                       lines
       pass8bits                       Force   BODY=8BITMIME   to   ESMTP
                                       listener
       dropstatus                      Strip Status and  X-Mozilla-Status
                                       lines out of incoming mail
       dropdelivered                   Strip  Delivered-To  lines  out of
                                       incoming mail
       mimedecode                      Convert quoted-printable to  8-bit
                                       in MIME messages
       idle                            Idle   waiting  for  new  messages
                                       after each poll (IMAP only)
       no keep            -K           Delete seen messages  from  server
                                       (default)
       no flush                        Don't   flush  all  seen  messages
                                       before querying (default)
       no fetchall                     Retrieve   only    new    messages
                                       (default)
       no rewrite                      Don't rewrite headers
       no stripcr                      Don't   strip   carriage   returns
                                       (default)
       no forcecr                      Don't force  carriage  returns  at
                                       EOL (default)
       no pass8bits                    Don't force BODY=8BITMIME to ESMTP
                                       listener (default)
       no dropstatus                   Don't    drop    Status    headers
                                       (default)
       no dropdelivered                Don't  drop  Delivered-To  headers
                                       (default)
       no mimedecode                   Don't convert quoted-printable  to
                                       8-bit in MIME messages (default)
       no idle                         Don't   idle   waiting   for   new
                                       messages  after  each  poll  (IMAP
                                       only)
       limit              -l           Set message size limit
       warnings           -w           Set message size warning interval
       batchlimit         -b           Max   #  messages  to  forward  in
                                       single connect
       fetchlimit         -B           Max # messages to fetch in  single
                                       connect
       fetchsizelimit                  Max  #  message  sizes to fetch in
                                       single transaction

       fastuidl                        Use binary search for first unseen
                                       message (POP3 only)
       expunge            -e           Perform  an  expunge  on every #th
                                       message (IMAP and POP3 only)
       properties                      String   value   is   ignored   by
                                       fetchmail    (may   be   used   by
                                       extension scripts)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

DEBUGGING FETCHMAIL

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

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

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

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

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

               file `which fetchmail`

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

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

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

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

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

INTERACTION WITH RFC 822

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

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

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

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

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

CONFIGURATION EXAMPLES

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

       The basic format is:

              poll SERVERNAME protocol PROTOCOL username NAME password PASSWORD

       Example:

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

       Or, using some abbreviations:

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

       Multiple servers may be listed:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

THE USE AND ABUSE OF MULTIDROP MAILBOXES

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

SOCKS

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

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

       env SOCKS_CONF=/dev/null fetchmail

EXIT CODES

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

       The exit codes returned by fetchmail are as follows:

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

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

              || [ $? -eq 1 ]

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

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

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

       4      Some sort of fatal protocol error was detected.

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

       6      The run control file had bad permissions.

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

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

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

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

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

       12     BSMTP batch file could not be opened.

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

       14     Server busy indication.

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

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

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

FILES

       ~/.fetchmailrc
            default run control file

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

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

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

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

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

ENVIRONMENT

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

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

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

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

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

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

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

SIGNALS

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

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

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

BUGS, LIMITATIONS, AND KNOWN PROBLEMS

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

AUTHOR

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

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

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

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

SEE ALSO

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

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

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

APPLICABLE STANDARDS

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

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

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

       POP2:
            RFC 937

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

       APOP:
            RFC 1939.

       RPOP:
            RFC 1081, RFC 1225.

       IMAP2/IMAP2BIS:
            RFC 1176, RFC 1732.

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

       ETRN:
            RFC 1985.

       ODMR/ATRN:
            RFC 2645.

       OTP: RFC 1938.

       LMTP:
            RFC 2033.

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

       TLS: RFC 2595.