.\" For license terms, see the file COPYING in this directory.
-.TH fetchmail LOCAL
+.TH fetchmail 1
.SH NAME
-fetchmail \- fetch mail from a POP or IMAP server
+fetchmail \- fetch mail from a POP, IMAP, or ETRN-capable server
+
.SH SYNOPSIS
-.B fetchmail
-[\fI options \fR] \fI [mailserver...]\fR
+\fBfetchmail\fR [\fIoptions\fR] [\fImailserver...\fR]
+
.SH DESCRIPTION
.I fetchmail
is a mail-retrieval and forwarding utility; it fetches
The
.I fetchmail
program can gather mail from servers supporting any of the common
-mail-retrieval protocols: POP2 (as specified in RFC 937), POP3 (RFC
-1939), IMAP2bis (as implemented by the 4.4BSD imapd program), and
-IMAP4 (as specified by RFC 1730). It can use (but does not require)
-the LAST facility removed from later POP3 versions.
+mail-retrieval protocols: POP2, POP3, IMAP2bis, and IMAP4. It can
+also use the ESMTP ETRN extension. (The RFCs describing all these
+protocols are listed at the end of this document.)
.PP
While
.I fetchmail
\fIsendmail\fR(8) but your system may use a different one such
as \fIsmail\fR, \fImmdf\fR, or \fIqmail\fR). All the delivery-control
mechanisms (such as \fI.forward\fR files) normally available through
-your system MDA will therefore work.
+your system MDA and local delivery agents will therefore work.
.PP
The behavior of
.I fetchmail
.I ~/.fetchmailrc
declarations.
.PP
+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 server in your
+.I ~/.fetchmailrc
+file will be queried.
+.PP
To facilitate the use of
.I fetchmail
In scripts, pipelines, etc., it returns an appropriate exit code upon
termination -- see EXIT CODES below.
+
.SH OPTIONS
The following options modify the behavior of \fIfetchmail\fR. It is
seldom necessary to specify any of these once you have a
working \fI.fetchmailrc\fR file set up.
+.PP
+Almost all options have a corresponding keyword which can be used to
+declare them in a
+.I fetchmailrc
+file.
+.PP
+Some special options are not covered here, but are documented insttead
+in sections on AUTHENTICATION and DAEMON MODE which follows.
+.SS General Options
.TP
-.B \-a, --all
-Retrieve both old (seen) and new messages from the mailserver. The
-default is to fetch only messages the server has not marked seen.
-Note that POP2 retrieval behaves as though --all is always on (see
-RETRIEVAL FAILURE MODES below).
-.TP
-.B \-l, --limit
-Takes a maximum octet size argument. Messages larger than this size
-will not be fetched, not be marked seen, and will be left on the
-server (in foreground sessions, the progress messages will note that
-they are "oversized"). The --all option overrides this one. This
-option is intended for those need to strictly control fetch time
-in interactive mode. It may not be used with daemon mode,
-as users would never receive a notification that messages were waiting.
-.TP
-.B \-S host, --smtphost host
-Specify a host to forward mail to (other than localhost).
-.TP
-.B \-m, \--mda
-You can force mail to be passed to an MDA directly (rather than
-forwarded to port 25) with the -mda or -m option. If \fIfetchmail\fR
-is running as root, it sets its userid to that of the target user
-while delivering mail through an MDA. Some possible MDAs are
-"/usr/sbin/sendmail -oem", "/usr/lib/sendmail -oem",
-"/usr/bin/formail", and "/usr/bin/deliver". Local delivery addresses
-will be inserted into the MDA command wherever you place a %s. Do
-\fInot\fR use an MDA like
-"sendmail -oem -t" that dispatches on the contents of To/Cc/Bcc, it
-will create mail loops and bring the just wrath of many postmasters
-down upon your head.
-.TP
-.B \-F, --flush
-POP3/IMAP only. Delete old (previously retrieved) messages from the mailserver
-before retrieving new messages.
+.B \-V, --version
+Displays the version information for your copy of
+.I fetchmail.
+No mail fetch is performed.
+Instead, for each server specified, all option information
+that would be computed if
+.I 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.
.TP
.B \-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 doesn't play well with queries to multiple sites, and
-is ignored in daemon mode. It's also prone to false positives if
-you leave read but undeleted mail in your server mailbox.
+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. 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.
.TP
-.B \-f pathname, --fetchmailrc pathname
-Specify a non-default name for the
-.I .fetchmailrc
-run control file.
+.B \-s, --silent
+Silent mode. Suppresses all progress/status messages that are normally
+echoed to standard error during a fetch. The --verbose option
+overrides this.
.TP
-.B \-i pathname, --idfile pathname
-Specify an alternate name for the .fetchids file used to save POP3
-UIDs.
+.B \-v, --verbose
+Verbose mode. All control messages passed between
+.I fetchmail
+and the mailserver are echoed to stderr. Overrides --silent.
+.SS Disposal Options
+.TP
+.B \-a, --all
+(Keyword: fetchall)
+Retrieve both old (seen) and new messages from the mailserver. The
+default is to fetch only messages the server has not marked seen.
+Note that POP2 retrieval behaves as though --all is always on (see
+RETRIEVAL FAILURE MODES below) and this option does not work with ETRN.
.TP
.B \-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
.B keep
-option causes retrieved messages to remain in your folder on the mailserver.
+option causes retrieved messages to remain in your folder on the
+mailserver. This option does not work with ETRN.
.TP
-.B \-K, --kill
+.B \-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 \fBnokill\fR in your \fI.fetchmailrc\fR.
+you have specified a default of \fBkeep\fR in your
+\fI.fetchmailrc\fR. This option is forced on with ETRN.
+.TP
+.B \-F, --flush
+POP3/IMAP only. Delete old (previously retrieved) messages from the mailserver
+before retrieving new messages. This option does not work with ETRN.
+.SS Protocol and Query Options
.TP
.B \-p, \--protocol proto
+(Keyword: proto[col])
Specify the protocol to used when communicating with the remote
mailserver. If no protocol is specified,
.I fetchmail
.I proto
may be one of the following:
.RS
-.IP IMAP
-IMAP2bis, a compatible subset of IMAP4.
.IP POP2
Post Office Protocol 2
.IP POP3
Post Office Protocol 3
.IP APOP
Use POP3 with MD5 authentication.
+.IP RPOP
+Use POP3 with RPOP authentication.
.IP KPOP
-Use POP3 with Kerberos authentication on port 1109.
+Use POP3 with Kerberos V4 authentication on port 1109.
+.IP IMAP
+IMAP2bis, IMAP4, or IMAP4rev1 (\fIfetchmail\fR autodetects their capabilities).
+.IP IMAP-K4
+IMAP4, or IMAP4rev1 (\fIfetchmail\fR autodetects their capabilities)
+with RFC 1731 Kerberos v4 authentication.
+.IP ETRN
+Use the ESMTP ETRN option.
.RE
+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. 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.
+.TP
+.B \-U, --uidl
+(Keyword: uidl)
+Force UIDL use (effective only with POP3). Force client-side tracking
+of `newness' of messages. Use with `keep' to use a mailbox as a baby
+news drop for a group of users; if the mailbox is periodically purged,
+every member will get a chance to read the message.
.TP
.B \-P, --port
+(Keyword: port)
The option permits you to specify a TCP/IP port to connect on.
This option will seldom be necessary as all the supported protocols have
well-established default port numbers.
.TP
-.B \-A, --auth
-This option permits you to specify an authentication type (see USER
-AUTHENTICATION below for details). The possible values are
-\&`\fBpassword\fR' and `\fBkerberos\fR'. This option is provided
-primarily for developers; choosing KPOP protocol automatically selects
-Kerberos authentication, and all other alternatives use ordinary
-password authentication (though APOP uses a generated one-time
-key as the password).
+.B \-r folder, --folder folder
+(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 or ETRN.
+.SS Delivery Control Options
.TP
-.B \-r folder, --remote folder
-Causes a specified non-default mail folder on the mailserver to be retrieved.
-The syntax of the folder name is server dependent, as is the default
-behavior when no folder is specified. This option is not available
-under POP3.
+.B \-S host, --smtphost host
+(Keyword: smtp[host])
+Specify a hunt list of hosts to forward mail to (one or more
+hostnames, comma-separated). In ETRN mode, set the host that the
+mailserver is asked to ship mail to. Hosts are tried in list order;
+the first one that is up becomes the forwarding or ETRN target for the
+current run.
.TP
-.B \-s, --silent
-Silent mode. Suppresses all progress/status messages that are normally
-echoed to standard error during a fetch. The --verbose option
-overrides this.
+.B \-m, \--mda
+(Keyword: mda)
+You can force mail to be passed to an MDA directly (rather than
+forwarded to port 25) with the -mda or -m option. If \fIfetchmail\fR
+is running as root, it sets its userid to that of the target user
+while delivering mail through an MDA. Some possible MDAs are
+"/usr/sbin/sendmail -oem", "/usr/lib/sendmail -oem",
+"/usr/bin/formail", and "/usr/bin/deliver". Local delivery addresses
+will be inserted into the MDA command wherever you place a %s. Do
+\fInot\fR use an MDA invocation like
+"sendmail -oem -t" that dispatches on the contents of To/Cc/Bcc, it
+will create mail loops and bring the just wrath of many postmasters
+down upon your head.
+.SS Resource Limit Control Options
.TP
-.B \-v, --verbose
-Verbose mode. All control messages passed between
+.B \-l, --limit
+(Keyword: limit)
+Takes a maximum octet size argument. Messages larger than this size
+will not be fetched, not be marked seen, and will be left on the
+server (in foreground sessions, the progress messages will note that
+they are "oversized"). 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 in interactive mode. It may not be used
+with daemon mode, as users would never receive a notification that
+messages were waiting. This option does not work with ETRN.
+.TP
+.B -b, --batchlimit
+(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
+\fBsendmail\fR(8) normally initiates delivery of a message immediately
+after receiving the message terminator, some SMTP listeners are not so
+prompt. MTAs like \fIqmail\fR(8) and \fIsmail\fR(8) may wait till the
+delivery socket is shut down to deliver. This may produce annoying
+delays when
+.IR fetchmail (8)
+is processing very large batches. Setting the batch limit to some
+nonzero size will prevent these delays.
+This option does not work with ETRN.
+.TP
+.B -B, --fetchlimit
+(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.
+.TP
+.B -e, --expunge
+(keyword: expunge)
+When talking to an IMAP server,
.I fetchmail
-and the mailserver are echoed to stderr. Overrides --silent.
+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. If you specify this option to an integer N,
+it tells
+.I 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, POP2, or POP3.
+.SS Authentication Options
.TP
.B \-u 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
.I fetchmail.
See USER AUTHENTICATION below for a complete description.
.TP
+.B \-I specification, --interface specification
+(Keyword: interface)
+Require that a specific interface device be up and have a specific local
+IP address (or range) before polling. Frequently
+.I 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:
+.sp
+ interface/iii.iii.iii.iii/mmm.mmm.mmm.mmm
+.sp
+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.
+.TP
+.B \-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. This option is currently only supported under Linux.
+.TP
+.B \-A, --auth
+(Keyword: auth[enticate])
+This option permits you to specify a preauthentication type (see USER
+AUTHENTICATION below for details). The possible values are
+\&`\fBpassword\fR' and `\fBkerberos\fR' (or, for excruciating
+exactness, `\fBkerberos_v4\fR'). This option is provided
+primarily for developers; choosing KPOP protocol automatically selects
+Kerberos preauthentication, and all other alternatives use
+password authentication (though APOP uses a generated one-time
+key as the password and IMAP-K4 uses RFC1731 Kerberos v4 authentication).
+This option does not work with ETRN.
+.SS Miscellaneous Options
+.TP
+.B \-f pathname, --fetchmailrc pathname
+Specify a non-default name for the
+.I .fetchmailrc
+run control file. Unless the --version option is also on, the file must have
+permissions no more open than 0600 (u=rw,g=,o=) or else be /dev/null.
+.TP
+.B \-i pathname, --idfile pathname
+Specify an alternate name for the .fetchids file used to save POP3
+UIDs.
+.TP
.B \-n, --norewrite
+(Keyword: no rewrite)
Normally,
.I fetchmail
edits RFC-822 address headers (To, From, Cc, Bcc, and Reply-To) in
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, the rewrite option is ineffective.
.TP
-.B -b, --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). While \fBsendmail\fR(8) normally
-initiates delivery of a message immediately after receiving the
-message terminator, some SMTP listeners are not so prompt. MTAs like
-\fIqmail\fR(8) and \fsmail\fR(8) will wait till the delivery socket is
-shut down to deliver. This may produce annoying delays when
-.IR fetchmail (8)
-is processing very large batches. Setting the batch limit to some
-nonzero size will prevent these delays.
-.TP
-.B \-V, --version
-Displays the version information for your copy of
-.I fetchmail.
-No mail fetch is performed.
-Instead, for each server specified, all option information
-that would be computed if
-.I 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.
-.PP
-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 server in your
-.I ~/.fetchmailrc
-file will be queried.
+.B -E, --envelope
+(Keyword: envelope)
+This option changes the header
+.I fetchmail
+assumes will carry a copy of the mail's envelope address. Normally
+this is `X-Envelope-To' but as this header is not standard, 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, and it should not be necessary
+unless you have globally disabled Received parsing with `no envelope'
+in the \fI.fetchmailrc\fR file.
+
.SH USER AUTHENTICATION
+Every mode except ETRN requires authentication of the client.
Normal user authentication in
.I fetchmail
is very much like the authentication mechanism of
.I fetchmail
in daemon mode or with scripts.
.PP
+If you do not specify a password, and
+.I fetchmail
+cannot extract one from your
+.I .fetchmailrc
+file, it will look for a
+.I .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. See the
+.IR ftp (1)
+man page for details of the syntax of the
+.I .netrc
+file. (This feature may allow you to avoid duplicating password
+information in more than one file.)
+.PP
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.
.PP
+Early versions of POP3 (RFC1081, RFC1225) supported a crude form of
+independent authentication using the
+.I 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
+.I fetchmail
+(you can specify `protocol RPOP' to have the program send `RPOP'
+rather than `PASS') but its use is strongly discouraged. This
+facility was vulnerable to spoofing and was withdrawn in RFC1460.
+.PP
RFC1460 introduced APOP authentication. In this variant of POP3,
you register an APOP password on your server host (the program
to do this with on the server is probably called \fIpopauth\fR(8)). You
checking its authorization database.
.PP
If your \fIfetchmail\fR was built with Kerberos support and you specify
-Kerberos authentication (either with --auth or the \fI.fetchmailrc\fR
-option \fBauthenticate kerberos\fR) it will try to get a Kerberos
+Kerberos preauthentication (either with --auth or the \fI.fetchmailrc\fR
+option \fBauthenticate kerberos_v4\fR) it will try to get a Kerberos
ticket from the mailserver at the start of each query.
+.PP
+If you use IMAP-K4, \fIfetchmail\fR will expect the IMAP server to have
+RFC1731-conformant AUTHENTICATE KERBEROS_V4 capability, and will use it.
+.PP
+If you are using POP3, and the server issues a one-time-password
+challenge conforming to RFC1938, \fIfetchmail\fR will use your
+password as a pass phrase to generate the required response. This
+avoids sending secrets over the net unencrypted.
+.PP
+Compuserve's RPA authentication (similar to APOP) is supported. If
+you are using POP3, and the RPA code has been compiled into your
+binary, and you query a server in the Compuserve csi.com domain,
+\fIfetchmail\fR will try to perform an RPA pass-phrase authentication
+instead of sending over the password en clair.
+
.SH DAEMON MODE
The
.B --daemon
file (except those explicitly excluded with the `skip' verb) once
every fifteen minutes.
.PP
+It is possible to set a polling interval
+in your
+.I ~/.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.
+.PP
Only one daemon process is permitted per user; in daemon mode,
.I fetchmail
makes a per-user lockfile to guarantee this. The option
.B --quit
will kill a running daemon process. Otherwise, calling fetchmail with
a daemon in the background sends a wakeup signal to the daemon,
-forcing it to poll mailservers immediately.
+forcing it to poll mailservers immediately. (The wakeup signal is
+SIGHUP if fetchmail is running as root, SIGUSR1 otherwise.)
.PP
The
.B -t
or
.B --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, \fIfetchmail\fR will hang up on it.
-Without such a timeout \fIfetchmail\fR might hang up indefinitely
-trying to fetch mail from a down host. This would be particularly
-annoying for a \fIfetchmail\fR running in background.
+option (keyword: timeout)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,
+\fIfetchmail\fR will hang up on it. Without such a timeout
+\fIfetchmail\fR might hang up indefinitely trying to fetch mail from a
+down host. This would be particularly annoying for a \fIfetchmail\fR
+running in background.
.PP
The
.B -L
or
.B --logfile
-option allows you to redirect status messages emitted while in daemon
-mode 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.
+option (keyword: set logfile) allows you to redirect status messages
+emitted while detached 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.
+.PP
+The
+.B --syslog
+option (keyword: syslog) allows you to redirect status and error
+messages emitted to the
+.IR syslog (3)
+system daemon if available.
+Messages are logged with an id of \fBfetchmail\fR, the facility \fBLOG_MAIL\fR,
+and priorities \fBLOG_ERR\fR, \fBLOG_ALERT\fR or \fBLOG_INFO\fR.
+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 \fI.fetchmailrc\fR
+file are still written to stderr, or the specified log file if the
+.B -L
+or
+.B --logfile
+option was used.
.PP
The
.B \-N
-or --nodetach option suppresses detachment of the daemon process
-from its control terminal. This is primarily useful for debugging.
-.PP
-Note that while running in daemon mode, transient errors (such as DNS
-failures or sendmail delivery refusals) effectively 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.
+or --nodetach option suppresses backgrounding and detachment of the
+daemon process from its control terminal. This is primarily useful
+for debugging. Note that this also causes the logfile option to be
+ignored (though perhaps it shouldn't).
+.PP
+Note that while running in daemon mode polling a POP2 or POP3 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.)
+
.SH RETRIEVAL FAILURE MODES
The protocols \fIfetchmail\fR uses to talk to mailservers are next to
bulletproof. In normal operation forwarding to port 25, no message is
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
\fIfetchmail --keep\fR will be both undeleted and marked old.
+.PP
+In ETRN mode, \fIfetchmail\fR 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.
+
+.SH SPAM FILTERING
+Many SMTP listeners allow administrators to set up `spam filters' that
+block unsolicited email from specified domains. A MAIL FROM line that
+triggers this feature will elicit an SMTP response which
+(unfortunately) varies according to the listener.
+.PP
+Newer versions of
+.I sendmail
+return an error code of 571. This return value
+is blessed by RFC1893 as "Delivery not authorized, message refused".
+.PP
+According to current drafts of the replacement for RFC821, 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].").
+.PP
+The
+.I exim
+MTA returns 501 "Syntax error in parameters or arguments" , but will
+move to 550 soon.
+.PP
+The
+.I fetchmail
+code recognizes any of these error codes and discards the message. This is the
+.I only
+circumstance under which fetchmail ever discards mail.
+.P
+If
+.I 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.
+
.SH THE RUN CONTROL FILE
-The preferred way to set up fetchmail (and the only way if you want to
-avoid specifying passwords each time it runs) is to write a
-\&\fI.fetchmailrc\fR file in your home directory. To protect the security
-of your passwords, your \fI~/.fetchmailrc\fR may not have more than
-600 (u=rw,g=,o=) permissions;
+The preferred way to set up fetchmail is to write a
+\&\fI.fetchmailrc\fR file in your home directory. When there is a
+conflict between the command-line arguments and the arguments in this
+file, the command-line arguments take precedence.
+.PP
+To protect the security of your passwords, when --version is not on
+your \fI~/.fetchmailrc\fR may not have more than 0600 (u=rw,g=,o=) permissions;
.I fetchmail
will complain and exit otherwise.
.PP
be executed when
.I fetchmail
is called with no arguments.
+.SS Run Control Syntax
.PP
Comments begin with a '#' and extend through the end of the line.
-Otherwise the file consists of a series of free-format server entries
-or global option statement.
-.PP
-Any amount of whitespace separates keywords, tokens, or strings in
-server entries, but is otherwise ignored (except that whitespace
-enclosed in double quotes is treated as part of the string). Keywords
-and identifiers are case sensitive. You may use standard C-style
-escapes (\en, \et, \eb, octal, and hex) to embed non-printable
-characters or string delimiters in strings. When there is a conflict
-between the command-line arguments and the arguments in this file, the
-command-line arguments take precedence.
+Otherwise the file consists of a series of server entries or global
+option statements in a free-format, token-oriented syntax.
+.PP
+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). An unquoted
+string is any whitespace-delimited token that is neither numeric, string
+quoted nor contains the special characters `,', `;', `:', or `='.
+.PP
+Any amount of whitespace separates tokens in server entries, but is
+otherwise ignored. You may use standard C-style escapes (\en, \et,
+\eb, octal, and hex) to embed non-printable characters or string
+delimiters in strings.
.PP
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 descriptions.
+number of user descriptions. Note: the most common cause of syntax
+errors is mixing up user and server options.
.PP
+For backward compatibility, the word `server' is a synonym for `poll'.
+.PP
+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.
+.PP
+.SS Poll vs. Skip
The `poll' verb tells fetchmail to query this host when it is run with
no arguments. The `skip' verb tells
.I fetchmail
line. (The `skip' verb allows you to experiment with test entries
safely, or easily disable entries for hosts that are temporarily down.)
.PP
-Legal server options are:
-
- protocol (or proto)
- port
- authenticate (or auth)
- timeout
- aka
-
-Legal user options are
-
- username (or user)
- is
- to
- password (or pass)
- remotefolder (or remote)
- smtphost (or smtp)
- mda
- keep
- flush
- fetchall
- rewrite
- nokeep
- noflush
- nofetchall
- norewrite
-.PP
-All options correspond to the obvious command-line arguments except
-four: `aka', `is', `to', and `password'.
+.SS Keyword/Option Summary
+Here are the legal server options. Keyword suffixes enclosed in
+square brackets are optional. Those corresponding to command-line
+options are followed by `-' and the appropriate option letter.
+
+.TS
+l l lw34.
+Keyword Opt Function
+_
+via \& T{
+Specify DNS name of mailserver, overriding poll name
+T}
+proto[col] -p T{
+Specify protocol (case insensitive):
+POP2, POP3, IMAP, IMAP-K4, APOP, KPOP
+T}
+port -P T{
+Specify TCP/IP service port
+T}
+auth[enticate] -A T{
+Set preauthentication type (default `password')
+T}
+timeout -t T{
+Server inactivity timout in seconds (default 300)
+T}
+envelope -E T{
+Specify envelope-address header name
+T}
+no envelope \& T{
+Disable looking for envelope address
+T}
+aka \& T{
+Specify alternate DNS names of mailserver
+T}
+interface -I T{
+specify IP interface(s) that must be up for server poll to take place
+T}
+monitor -M T{
+Specify IP address to monitor for activity
+T}
+dns \& T{
+Enable DNS lookup for multidrop (default)
+T}
+no dns \& T{
+Disable DNS lookup for multidrop
+T}
+uidl -U T{
+Force POP3 to use client-side UIDLs
+T}
+no uidl \& T{
+Turn off POP3 use of client-side UIDLs (default)
+T}
+.TE
+
+Here are the legal user options:
+
+.TS
+l l lw34.
+Keyword Opt Function
+_
+user[name] -u T{
+Set remote user name
+(local user name if name followed by `here')
+T}
+is \& T{
+Connect local and remote user names
+T}
+to \& T{
+Connect local and remote user names
+T}
+pass[word] \& T{
+Specify remote account password
+T}
+folder -r T{
+Specify remote folder to query
+T}
+smtphost -S T{
+Specify smtp host(s) to forward to
+T}
+mda -m T{
+Specify MDA for local delivery
+T}
+preconnect \& T{
+Command to be executed before each connection
+T}
+postconnect \& T{
+Command to be executed after each connection
+T}
+keep -k T{
+Don't delete seen messages from server
+T}
+flush -F T{
+Flush all seen messages before querying
+T}
+fetchall -a T{
+Fetch all messages whether seen or not
+T}
+rewrite \& T{
+Rewrite destination addresses for reply (default)
+T}
+stripcr \& T{
+Strip carriage returns from ends of lines
+T}
+forcecr \& T{
+Force carriage returns at ends of lines
+T}
+pass8bits \& T{
+Force BODY=8BITMIME to ESMTP listener
+T}
+dropstatus \& T{
+Strip Status lines out of incoming mail
+T}
+no keep -K T{
+Delete seen messages from server (default)
+T}
+no flush \& T{
+Don't flush all seen messages before querying (default)
+T}
+no fetchall \& T{
+Retrieve only new messages (default)
+T}
+no rewrite \& T{
+Don't rewrite headers
+T}
+no stripcr \& T{
+Don't strip carriage returns (default)
+T}
+no forcecr \& T{
+Don't force carriage returns at EOL (default)
+T}
+no pass8bits \& T{
+Don't force BODY=8BITMIME to ESMTP listener (default)
+T}
+no dropstatus \& T{
+Don't drop Status headers (default)
+T}
+limit -l T{
+Set message size limit
+T}
+batchlimit -b T{
+Max # messages to fetch in single connect
+T}
+fetchlimit -B T{
+Max # messages to forward in single connect
+T}
+expunge -e T{
+Perform an expunge on every #th message (IMAP only)
+T}
+syslog \& T{
+Do error logging through syslog(3).
+T}
+.TE
.PP
-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
-.IR 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.
+Remember that all user options must \fIfollow\fR all server options.
+.SS Keywords Not Corresponding To Option Switches
+.PP
+The `folder' and `smtphost' options (unlike their command-line
+equivalents) can take a space- or comma-separated list of names
+following them.
+.PP
+All options correspond to the obvious command-line arguments, except
+the following: `via', `interval', `aka', `is', `to', `dns'/`no dns',
+\&`password', \&`preconnect', \&`postconnect', `localdomains',
+\&`stripcr'/`no stripcr', \&`forcecr'/`no forcecr', `pass8bits'/`no
+pass8bits' `dropstatus/no dropstatus', and `no envelope'.
+.PP
+The `via' option is for use with ssh, or 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).
+If the `via' name is `localhost', the poll name will also still be
+used as a possible match in multidrop mode; otherwise the `via' name
+will be used instead and the poll name will be purely a label.
+.PP
+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.
.PP
The `is' or `to' keywords associate the following local (client)
name(s) (or server-name to client-name mappings separated by =) with
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 To, Cc, and Bcc headers.
+to that local username regardless of the message's Received, To, Cc,
+and Bcc headers. In this case
+.I fetchmail
+never does DNS lookups.
.PP
When there is more than one local name (or name mapping) the
-\fIfetchmail\fR code does look at the To, Cc, and Bcc headers of
-retrieved mail. When a declared mailserver username is recognized, its
-local mapping is added to the list of local recipients. If
-\fIfetchmail\fR cannot recognize any mailserver usernames, the default
-recipient is the calling user.
+\fIfetchmail\fR code does look 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', `localdomains', and `aka' for details on how matching
+addresses are handled. If \fIfetchmail\fR cannot match any mailserver
+usernames or localdomain addresses, the default recipient is the
+calling user.
+.PP
+The `dns' option (normally on) controls the way addresses from
+multidrop mailboxes are checked. On, it enables logic to check each
+host address that doesn't 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.
+.PP
+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
+.IR 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.
+.PP
+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 \fInot\fR
+applied).
+.PP
+If you are using `localdomains', you may also need to specify \&`no
+envelope', which disables \fIfetchmail\fR'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.
.PP
The \fBpassword\fR option requires a string argument, which is the password
to be used with the entry's server.
.PP
-The \fBaliases\fR option declares names that are recognized as OK for
-local delivery. Your local name is automatically one of these; the
-aliases directive can be used to declare others.
+The `preconnect' keyword allows you to specify a shell command to be
+executed just before each time
+.I fetchmail
+establishes a mailserver connection. This may be useful if you are
+attempting to set up secure POP connections with the aid of
+.IR ssh (1).
+If the command returns a nonzero status, the poll of that mailserver
+will be aborted.
+.PP
+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.
+.PP
+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).
.PP
-Legal protocol identifiers are
+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.
+.PP
+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,
+.I 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,
+.I 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.
+.PP
+The `dropstatus' option controls whether nonempty 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
+client. 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.)
+.PP
+.SS 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'
+.PP
+Legal protocol identifiers for use with the `protocol' keyword are:
auto (or AUTO)
pop2 (or POP2)
pop3 (or POP3)
imap (or IMAP)
+ imap-k4 (or IMAP-K4)
apop (or APOP)
kpop (or KPOP)
ticket at the start of each query instead, and send an arbitrary
string as the password.
.PP
-Specifying `kpop' sets POP3 protocol over port 1109 with Kerberos
-authentication. These defaults may be overridden by later options.
-.PP
-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.
-.PP
-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'
-.PP
-For backward compatibility, the word `server' is a syninym for `poll'.
-.PP
-There are currently two valid global option statements;
-\&`set batchlimit = ' followed by a number and sets the same global
-specified by the --batchlimit option, and `set logfile = ' followed
-by a string sets the same global specified by --logfile. In both
-cases, a command-line option will override.
+Specifying `kpop' sets POP3 protocol over port 1109 with Kerberos V4
+preauthentication. These defaults may be overridden by later options.
.PP
+There are currently three global option statements; `set logfile = '
+followed by a string sets the same global specified by --logfile. A
+command-line --logfile option will override this. 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. Finally, `set syslog' sends log
+messages to syslogd(8).
+
+.SH CONFIGURATION EXAMPLES
Basic format is:
.nf
It's possible to specify more than one user per server (this is only
likely to be useful when running fetchmail in daemon mode as root).
-The `user' keyword leads off a user description, and every user
-description except optionally the first one must include it. (If the
-first description lacks the `user' keyword, the name of the
-invoking user is used.) Here's a contrived example:
+The `user' keyword leads off a user description, and every user specification
+in a multi-user entry must include it. Here's an example:
.nf
poll pop.provider.net proto pop3 port 3111
- pass gumshoe
user jsmith with pass secret1 is smith here
user jones with pass secret2 is jjones here
.fi
-This says that the user invoking \fIfetchmail\fR has the same username
-on pop.provider.net, and password `gumshoe' there.
-It also associates the local username `smith' with the pop.provider.net
-username `jsmith' and the local username `jones' with the pop.provider.net
-username `jjones'.
-.PP
-This example is contrived because, in practice, you are very unlikely
-to be specifying multiple users per server unless running it as root
-(thus the `pass gumshoe' would try to fetch root's mail on
-pop-provider.net, which is probably not what you want).
-In any case, we strongly recommend always having an explicit
-\&`user' clause when specifying multiple users per mailserver.
+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'.
.PP
Here's what a simple retrieval configuration for a multi-drop mailbox
looks like:
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'.
+.PP
+Here's an example of another kind of multidrop connection:
+
+.nf
+ poll pop.provider.net localdomains loonytoons.org:
+ user maildrop with pass secret1 to esr * here
+.fi
+
+This also says that the mailbox of account `maildrop' on the server is
+a multi-drop box. It tells fetchmail that any address in the
+loonytoons.org domain (including subdomain 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!
+.PP
+Here's an example configuration using ssh. The queries go through an
+ssh connecting local port 1234 to port 110 on mailhost.net; the
+preconnect command sets up the ssh.
+
+.nf
+poll mailhost.net via localhost port 1234 with pop3:
+ preconnect "ssh -f -L 1234:mailhost.net:110
+ mailhost.net sleep 20 </dev/null >/dev/null";
+.fi
+
.SH THE USE AND ABUSE OF MULTIDROP MAILBOXES
Use the multiple-local-recipients feature with caution -- it can bite.
-The fundamental problem is that by having your server toss several
-peoples' mail in a 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 addresses in the headers).
-This can't always be deduced from the headers, especially when mailing
-lists are involved.
+Also note that all multidrop features are ineffective in ETRN mode.
+
+.SS 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/Bcc headers). This `envelope
+address' is the address you need in order to reroute mail properly.
+.PP
+Sometimes
+.I fetchmail
+can deduce the envelope address. If the mailserver MTA is
+.I 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, \fIfetchmail\fR looks for
+envelope addresses in these lines; you can restore this default with
+-E "Received" or \&`envelope Received'.
+.PP
+Alternatively, 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-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 recopients) to all receivers of the
+messages; it is therefore regarded by some administrators as a
+security/privacy problem.
+.PP
+Sometimes, unfortunately, neither of these methods works. When they
+both fail, fetchmail must fall back on the contents of To/Cc/Bcc
+headers to try to determine recipient addressees -- and these are not
+reliable. In particular, mailing-list software often ships mail with
+only the list broadcast address in the To header.
+.PP
+When
+.I 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.
+.PP
+A related problem is that when you blind-copy a mail message, the Bcc
+information is carried \fIonly\fR as envelope address (it's not put
+in the headers fetchmail can see unless there is an X-Envelope
+header). Thus, blind-copying to someone who gets mail over a
+fetchmail link will fail unless the the mailserver host routinely
+writes X-Envelope or an equivalent header into messages in your maildrop.
+
.SS Good Ways To Use Multidrop Mailboxes
Multiple local names can be used to administer a mailing list from the
client side of a \fIfetchmail\fR collection. Suppose your name is
.PP
On your server, you can alias \&`fetchmail-friends' to `esr'; then, in
your \fI.fetchmailrc\fR, declare \&`to esr fetchmail-friends here'.
-Then, when mail including `fetchmail-friends' in any of its recipient
-lines gets fetched, the list name will be appended to the list of
+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 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!)
+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.
.PP
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
sent to the local user running
.IR fetchmail ,
but the program has no way to know that that's actually the right thing.
+
.SS Bad Ways To Abuse Multidrop Mailboxes
Multidrop mailboxes and
.I 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. If you have multiple local names declared,
+recipient address on it. Unless
.I fetchmail
-cannot know which to send it to! It will only go to the account
-running fetchmail (probably root).
+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.
.PP
-Matters are further complicated by the fact that sometimes
+If you're tempted to use
+.I 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 mode 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.
+.PP
+If you absolutely \fImust\fR use multidrop for this purpose, make sure
+your mailserver writes an envelope-address header that fetchmail can
+see. Otherwise you \fIwill\fR lose mail and it \fIwill\fR come back
+to haunt you.
+
+.SS Speeding Up Multidrop Checking
+Normally, when multiple user are declared
.I fetchmail
-\fIcan\fR in fact deduce the envelope address. If the server-side
-MTA is
-.I sendmail
-and the item of mail had just one recipient, the MTA will have written
-a `for' clause that gives the envelope addressee into its Received
-header. But this doesn't work for other MTAs, nor if there is more
-than one recipient.
+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.
+.PP
+This is the safest but also slowest 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
+.B all
+DNS aliases of the mailserver (and all MX names pointing at it)
+you can declare `no dns' to suppress DNS lookups entirely and
+\fIonly\fR match against the aka list.
+
.SH EXIT CODES
To facilitate the use of
.I fetchmail
.IP 0
One or more messages were successfully retrieved.
.IP 1
-There was no mail awaiting retrieval.
+There was no mail awaiting retrieval. (There may have been old mail still
+on the server but not selected for retrieval.)
.IP 2
An error was encountered when attempting to open a socket for the POP
connection. If you don't know what a socket is, don't worry about it --
.IP 6
The run control file had bad permissions.
.IP 7
-There was an error condition reported by the server (POP3 only).
+There was an error condition reported by the server. Can also
+fire if
+.I fetchmail
+timed out while waiting for the server.
.IP 8
-Exclusion error. This means
+Client-side exclusion error. This means
.I 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.
.IP 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".
+.IP 10
The
.I fetchmail.
run failed while trying to do an SMTP port open or transaction.
-.IP 10
+.IP 11
+Fatal DNS error. Fetchmail encountered an error while performing
+a DNS lookup at startup and could not proceed.
+.IP 11
Internal error. You should see a message on standard error with
details.
.PP
When
.I fetchmail
-queries more than one host, the returned status is that of the last
-host queried.
+queries more than one host, return status is 0 if \fIany\fR query
+successfully retrieved mail. Otherwise the returned error status is
+that of the last host queried.
+
.SH AUTHOR
Eric S. Raymond <esr@snark.thyrsus.com>.
-.SH BACKWARD COMPATIBILITY
-This program is descended
-from and replaces
+This program is descended from and replaces
.IR popclient ,
by Carl Harris <ceharris@mal.com>; the internals are quite different,
but some of its interface design is directly traceable to that
-ancestral program. Some effort has been made to preserve compatibility.
-.PP
-If called through a link named `popclient', \fIfetchmail\fR will look
-in ~/.poprc for its run control file. As long as the file does not
-use the removed `localfolder' option or `limit' (which now takes a
-maximum byte size rather than a line count), this will often work.
-(The new run control file syntax also has to be a little stricter
-about the order of options than the old, in order to support multiple
-user desriptions per server; thus you may have to rearrange things a
-bit.)
+ancestral program.
+
.SH FILES
.TP 5
~/.fetchmailrc
(used only with newer RFC1725-compliant POP3 servers supporting the
UIDL command).
.TP 5
-${TMPDIR}/fetchmail-${USER}
-lock file to help prevent concurrent runs.
+~/.netrc
+your FTP run control file, which (if present) will be searched for
+passwords as a last resort before prompting for one interactively.
+.TP 5
+~/.fetchmail
+lock file to help prevent concurrent runs (non-root mode).
+.TP 5
+/var/run/fetchmail.pid
+lock file to help prevent concurrent runs (root mode, Linux systems).
+.TP 5
+/etc/fetchmail.pid
+lock file to help prevent concurrent runs (root mode, systems without /var/run).
+
.SH ENVIRONMENT
For correct initialization,
.I fetchmail
requires either that both the USER and HOME environment variables are
correctly set, or that \fBgetpwuid\fR(3) be able to retrieve a password
entry from your user ID.
+
+.SH SIGNALS
+If a
+.I fetchmail
+daemon is running as root, SIGHUP wakes it up from its sleep phase and
+forces a poll of all non-skipped servers (this is in accordance with
+the usual conventions for system daemons).
+.PP
+If
+.I 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).
+.PP
+Running
+.I fetchmail
+in foreground while a background fetchmail is running will do
+whichever of these is appropriate to wake it up.
+
.SH BUGS AND KNOWN PROBLEMS
-Use of any of the supported protocols other than APOP or KPOP 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.
+The RFC822 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.
+.PP
+Use of any of the supported protocols other than POP3 with OTP or RPA, APOP,
+KPOP, IMAP-K4, or ETRN 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, the
+--interface option can be used to restrict polling to availability of
+a specific interface device with a specific local 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.
.PP
Send comments, bug reports, gripes, and the like to Eric S. Raymond
-<esr@thyrsus.com>.
+<esr@thyrsus.com>. An HTML FAQ is available at the fetchmail home
+page; surf to http://www.ccil.org/~esr/fetchmail or do a WWW search
+for pages with `fetchmail' in their titles.
+
.SH SEE ALSO
-elm(1), mail(1), sendmail(8), popd(8), imapd(8);
-RFC 937, RFC 1081, RFC1176, RFC 1225, RFC 1460, RFC 1725, RFC1939.
+elm(1), mail(1), sendmail(8), popd(8), imapd(8)
+.SH APPLICABLE STANDARDS
+.TP 5
+SMTP/ESMTP:
+RFC 821, RFC 1869, RFC 1652, RFC 1870, RFC1983, RFC 1985
+.TP 5
+mail:
+RFC 822
+.TP 5
+POP2:
+RFC 937
+.TP 5
+POP3:
+RFC 1081, RFC 1225, RFC 1460, RFC 1725, RFC 1939
+.TP 5
+APOP:
+RFC 1460, RFC 1725, RFC 1939
+.TP 5
+RPOP:
+RFC 1081, RFC 1225
+.TP 5
+IMAP2/IMAP2BIS:
+RFC 1176, RFC 1732
+.TP 5
+IMAP4:
+RFC 1730, RFC 1731, RFC 1732, RFC 2060, RFC 2061
+.TP 5
+ETRN:
+RFC 1985
+.TP 5
+OTP:
+RFC 1938
projects / ~andy / fetchmail / blobdiff