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Text File | 1998-10-28 | 77.8 KB | 1,849 lines

ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) NNNNAAAAMMMMEEEE fetchmail - fetch mail from a POP, IMAP, or ETRN-capable server SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS ffffeeeettttcccchhhhmmmmaaaaiiiillll [_o_p_t_i_o_n_s] [_m_a_i_l_s_e_r_v_e_r...] DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN _f_e_t_c_h_m_a_i_l 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 _e_l_m(1) or _M_a_i_l(1). The ffffeeeettttcccchhhhmmmmaaaaiiiillll utility can be run in a daemon mode to repeatedly poll one or more systems at a specified interval. The _f_e_t_c_h_m_a_i_l program can gather mail from servers supporting any of the common 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.) While _f_e_t_c_h_m_a_i_l 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. As each message is retrieved _f_e_t_c_h_m_a_i_l 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. The mail will then be delivered locally via your system's MDA (Mail Delivery Agent, usually _s_e_n_d_m_a_i_l(8) but your system may use a different one such as _s_m_a_i_l, _m_m_d_f, or _q_m_a_i_l). All the delivery-control mechanisms (such as ._f_o_r_w_a_r_d files) normally available through your system MDA and local delivery agents will therefore work. The behavior of _f_e_t_c_h_m_a_i_l is controlled by command-line options and a run control file, ~/._f_e_t_c_h_m_a_i_l_r_c, the syntax of which we describe below. Command-line options override ~/._f_e_t_c_h_m_a_i_l_r_c 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 server in your ~/._f_e_t_c_h_m_a_i_l_r_c file will be queried. To facilitate the use of _f_e_t_c_h_m_a_i_l In scripts, pipelines, etc., it returns an appropriate exit code upon termination Page 1 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) -- see EXIT CODES below. OOOOPPPPTTTTIIIIOOOONNNNSSSS The following options modify the behavior of _f_e_t_c_h_m_a_i_l. It is seldom necessary to specify any of these once you have a working ._f_e_t_c_h_m_a_i_l_r_c file set up. Almost all options have a corresponding keyword which can be used to declare them in a _f_e_t_c_h_m_a_i_l_r_c file. Some special options are not covered here, but are documented insttead in sections on AUTHENTICATION and DAEMON MODE which follows. GGGGeeeennnneeeerrrraaaallll OOOOppppttttiiiioooonnnnssss ----VVVV,,,, --------vvvveeeerrrrssssiiiioooonnnn Displays the version information for your copy of _f_e_t_c_h_m_a_i_l. No mail fetch is performed. Instead, for each server specified, all option information that would be computed if _f_e_t_c_h_m_a_i_l. 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. ----cccc,,,, --------cccchhhheeeecccckkkk 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. 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. ----ssss,,,, --------ssssiiiilllleeeennnntttt Silent mode. Suppresses all progress/status messages that are normally echoed to standard error during a fetch. The --verbose option overrides this. ----vvvv,,,, --------vvvveeeerrrrbbbboooosssseeee Verbose mode. All control messages passed between _f_e_t_c_h_m_a_i_l and the mailserver are echoed to stderr. Overrides --silent. DDDDiiiissssppppoooossssaaaallll OOOOppppttttiiiioooonnnnssss ----aaaa,,,, --------aaaallllllll (Keyword: fetchall) Retrieve both old (seen) and new messages from the mailserver. The default is to fetch Page 2 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 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. ----kkkk,,,, --------kkkkeeeeeeeepppp (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 kkkkeeeeeeeepppp option causes retrieved messages to remain in your folder on the mailserver. This option does not work with ETRN. ----KKKK,,,, --------nnnnooookkkkeeeeeeeepppp (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 kkkkeeeeeeeepppp in your ----FFFF,,,, --------fffflllluuuusssshhhh POP3/IMAP only. Delete old (previously retrieved) messages from the mailserver before retrieving new messages. This option does not work with ETRN. PPPPrrrroooottttooooccccoooollll aaaannnndddd QQQQuuuueeeerrrryyyy OOOOppppttttiiiioooonnnnssss ----pppp,,,, --------pppprrrroooottttooooccccoooollll pppprrrroooottttoooo (Keyword: proto[col]) Specify the protocol to used when communicating with the remote mailserver. If no protocol is specified, _f_e_t_c_h_m_a_i_l will try each of the supported protocols in turn, terminating after any successful attempt. _p_r_o_t_o may be one of the following: POP2 Post Office Protocol 2 POP3 Post Office Protocol 3 APOP Use POP3 with MD5 authentication. RPOP Use POP3 with RPOP authentication. KPOP Use POP3 with Kerberos V4 authentication on port 1109. IMAP IMAP2bis, IMAP4, or IMAP4rev1 (_f_e_t_c_h_m_a_i_l autodetects their capabilities). IMAP-K4 IMAP4, or IMAP4rev1 (_f_e_t_c_h_m_a_i_l autodetects their capabilities) with RFC 1731 Kerberos v4 authentication. ETRN Use the ESMTP ETRN option. Page 3 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 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. ----UUUU,,,, --------uuuuiiiiddddllll (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 RFC1725). Use with `keep' to use a mailbox as a baby news drop for a group of users. ----PPPP,,,, --------ppppoooorrrrtttt (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. ----rrrr ffffoooollllddddeeeerrrr,,,, --------ffffoooollllddddeeeerrrr ffffoooollllddddeeeerrrr (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. DDDDeeeelllliiiivvvveeeerrrryyyy CCCCoooonnnnttttrrrroooollll OOOOppppttttiiiioooonnnnssss ----SSSS hhhhoooosssstttt,,,, --------ssssmmmmttttpppphhhhoooosssstttt hhhhoooosssstttt (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. ----mmmm,,,, --------mmmmddddaaaa (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 _f_e_t_c_h_m_a_i_l 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 %T; the mail message's From address will be inserted where you place an %F. Do _n_o_t 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 Page 4 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) postmasters down upon your head. RRRReeeessssoooouuuurrrrcccceeee LLLLiiiimmmmiiiitttt CCCCoooonnnnttttrrrroooollll OOOOppppttttiiiioooonnnnssss ----llll,,,, --------lllliiiimmmmiiiitttt (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. ----bbbb,,,, --------bbbbaaaattttcccchhhhlllliiiimmmmiiiitttt (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 sssseeeennnnddddmmmmaaaaiiiillll(8) normally initiates delivery of a message immediately after receiving the message terminator, some SMTP listeners are not so prompt. MTAs like _q_m_a_i_l(8) and _s_m_a_i_l(8) may wait till the delivery socket is shut down to deliver. This may produce annoying delays when _f_e_t_c_h_m_a_i_l(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. ----BBBB,,,, --------ffffeeeettttcccchhhhlllliiiimmmmiiiitttt (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. ----eeee,,,, --------eeeexxxxppppuuuunnnnggggeeee (keyword: expunge) When talking to an IMAP server, _f_e_t_c_h_m_a_i_l 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 _f_e_t_c_h_m_a_i_l to only issue expunges on every Nth delete. An argument of zero suppresses expunges Page 5 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) entirely (so no expunges at all will be done until the end of run). This option does not work with ETRN, POP2, or POP3. AAAAuuuutttthhhheeeennnnttttiiiiccccaaaattttiiiioooonnnn OOOOppppttttiiiioooonnnnssss ----uuuu nnnnaaaammmmeeee,,,, --------uuuusssseeeerrrrnnnnaaaammmmeeee nnnnaaaammmmeeee (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 _f_e_t_c_h_m_a_i_l. See USER AUTHENTICATION below for a complete description. ----IIII ssssppppeeeecccciiiiffffiiiiccccaaaattttiiiioooonnnn,,,, --------iiiinnnntttteeeerrrrffffaaaacccceeee ssssppppeeeecccciiiiffffiiiiccccaaaattttiiiioooonnnn (Keyword: interface) Require that a specific interface device be up and have a specific local IP address (or range) before polling. Frequently _f_e_t_c_h_m_a_i_l 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. ----MMMM iiiinnnntttteeeerrrrffffaaaacccceeee,,,, --------mmmmoooonnnniiiittttoooorrrr iiiinnnntttteeeerrrrffffaaaacccceeee (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. ----AAAA,,,, --------aaaauuuutttthhhh Page 6 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) (Keyword: auth[enticate]) This option permits you to specify a preauthentication type (see USER AUTHENTICATION below for details). The possible values are `ppppaaaasssssssswwwwoooorrrrdddd' and `kkkkeeeerrrrbbbbeeeerrrroooossss' (or, for excruciating exactness, `kkkkeeeerrrrbbbbeeeerrrroooossss____vvvv4444'). 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. MMMMiiiisssscccceeeellllllllaaaannnneeeeoooouuuussss OOOOppppttttiiiioooonnnnssss ----ffff ppppaaaatttthhhhnnnnaaaammmmeeee,,,, --------ffffeeeettttcccchhhhmmmmaaaaiiiillllrrrrcccc ppppaaaatttthhhhnnnnaaaammmmeeee Specify a non-default name for the ._f_e_t_c_h_m_a_i_l_r_c 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. ----iiii ppppaaaatttthhhhnnnnaaaammmmeeee,,,, --------iiiiddddffffiiiilllleeee ppppaaaatttthhhhnnnnaaaammmmeeee Specify an alternate name for the .fetchids file used to save POP3 UIDs. ----nnnn,,,, --------nnnnoooorrrreeeewwwwrrrriiiitttteeee (Keyword: no rewrite) Normally, _f_e_t_c_h_m_a_i_l 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, the rewrite option is ineffective. ----EEEE,,,, --------eeeennnnvvvveeeellllooooppppeeee (Keyword: envelope) This option changes the header _f_e_t_c_h_m_a_i_l 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 ._f_e_t_c_h_m_a_i_l_r_c file. ----QQQQ,,,, --------qqqqvvvviiiirrrrttttuuuuaaaallll Page 7 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) (Keyword: qvirtual) The string assigned to this option will be removed from the user name found in the header specified with the _e_n_v_e_l_o_p_e option. This option is useful if you are using _f_e_t_c_h_m_a_i_l 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.userdom.dom.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. UUUUSSSSEEEERRRR AAAAUUUUTTTTHHHHEEEENNNNTTTTIIIICCCCAAAATTTTIIIIOOOONNNN Every mode except ETRN requires authentication of the client. Normal user authentication in _f_e_t_c_h_m_a_i_l is very much like the authentication mechanism of _f_t_p(_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 _f_e_t_c_h_m_a_i_l. 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 ----uuuu 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 ----uuuu option. e.g. if your login name is 'jsmith' on a machine named 'mailgrunt', you would start _f_e_t_c_h_m_a_i_l as follows: Page 8 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) fetchmail -u jsmith mailgrunt The default behavior of _f_e_t_c_h_m_a_i_l is to prompt you for your mailserver password before the connection is established. This is the safest way to use _f_e_t_c_h_m_a_i_l and ensures that your password will not be compromised. You may also specify your password in your ~/._f_e_t_c_h_m_a_i_l_r_c file. This is convenient when using _f_e_t_c_h_m_a_i_l in daemon mode or with scripts. If you do not specify a password, and _f_e_t_c_h_m_a_i_l cannot extract one from your ._f_e_t_c_h_m_a_i_l_r_c file, it will look for a ._n_e_t_r_c 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 _f_t_p(1) man page for details of the syntax of the ._n_e_t_r_c file. (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. Early versions of POP3 (RFC1081, RFC1225) supported a crude form of independent authentication using the _r_h_o_s_t_s 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 _f_e_t_c_h_m_a_i_l (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. 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 _p_o_p_a_u_t_h(8)). You put the same password in your ._f_e_t_c_h_m_a_i_l_r_c file. Each time _f_e_t_c_h_m_a_i_l logs in, it sends a cryptographically secure hash of your password and the server greeting time to the server, which can verify it by checking its authorization database. If your _f_e_t_c_h_m_a_i_l was built with Kerberos support and you specify Kerberos preauthentication (either with --auth or the ._f_e_t_c_h_m_a_i_l_r_c option aaaauuuutttthhhheeeennnnttttiiiiccccaaaatttteeee kkkkeeeerrrrbbbbeeeerrrroooossss____vvvv4444) it will try to get a Kerberos ticket from the mailserver at the start of each query. If you use IMAP-K4, _f_e_t_c_h_m_a_i_l will expect the IMAP server to Page 9 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) have RFC1731-conformant AUTHENTICATE KERBEROS_V4 capability, and will use it. If you are using POP3, and the server issues a one-time- password challenge conforming to RFC1938, _f_e_t_c_h_m_a_i_l 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 (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, _f_e_t_c_h_m_a_i_l will try to perform an RPA pass-phrase authentication instead of sending over the password en clair. DDDDAAAAEEEEMMMMOOOONNNN MMMMOOOODDDDEEEE The --------ddddaaaaeeeemmmmoooonnnn or ----dddd option runs _f_e_t_c_h_m_a_i_l in daemon mode. You must specify a numeric argument which is a polling interval in seconds. In daemon mode, _f_e_t_c_h_m_a_i_l puts itself in background and runs forever, querying each specified host and then sleeping for the given polling interval. Simply invoking fetchmail -d 900 will, therefore, poll all the hosts described in your ~/._f_e_t_c_h_m_a_i_l_r_c file (except those explicitly excluded with the `skip' verb) once every fifteen minutes. It is possible to set a polling interval in your ~/._f_e_t_c_h_m_a_i_l_r_c 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, _f_e_t_c_h_m_a_i_l makes a per-user lockfile to guarantee this. The option --------qqqquuuuiiiitttt 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. (The wakeup signal is SIGHUP if fetchmail is running as root, SIGUSR1 otherwise.) The ----tttt or --------ttttiiiimmmmeeeeoooouuuutttt 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, _f_e_t_c_h_m_a_i_l will Page 10 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) hang up on it. Without such a timeout _f_e_t_c_h_m_a_i_l might hang up indefinitely trying to fetch mail from a down host. This would be particularly annoying for a _f_e_t_c_h_m_a_i_l running in background. The ----LLLL or --------llllooooggggffffiiiilllleeee 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. The --------ssssyyyysssslllloooogggg option (keyword: syslog) allows you to redirect status and error messages emitted to the _s_y_s_l_o_g(3) system daemon if available. Messages are logged with an id of ffffeeeettttcccchhhhmmmmaaaaiiiillll, the facility LLLLOOOOGGGG____MMMMAAAAIIIILLLL, and priorities LLLLOOOOGGGG____EEEERRRRRRRR, LLLLOOOOGGGG____AAAALLLLEEEERRRRTTTT or LLLLOOOOGGGG____IIIINNNNFFFFOOOO. 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 ._f_e_t_c_h_m_a_i_l_r_c file are still written to stderr, or the specified log file if the ----LLLL or --------llllooooggggffffiiiilllleeee option was used. The --------iiiinnnnvvvviiiissssiiiibbbblllleeee option 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 ----NNNN 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). 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.) Page 11 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) RRRREEEETTTTRRRRIIIIEEEEVVVVAAAALLLL FFFFAAAAIIIILLLLUUUURRRREEEE MMMMOOOODDDDEEEESSSS The protocols _f_e_t_c_h_m_a_i_l 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 has acknowledged to _f_e_t_c_h_m_a_i_l that the message has been accepted for delivery. When forwarding to an MDA, however, there is more possibility of error (because there's no way for fetchmail to get a reliable positive acknowledgement from the MDA). The normal mode of _f_e_t_c_h_m_a_i_l 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 _f_e_t_c_h_m_a_i_l --_k_e_e_p). 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 _f_e_t_c_h_m_a_i_l must treat all messages as new all the time. But POP2 is obsolete, so this is unlikely. Under POP3, blame RFC1725. That version of the POP3 protocol specification removed the LAST command, and some POP servers follow it (you can verify this by invoking _f_e_t_c_h_m_a_i_l -_v to the mailserver and watching the response to LAST early in the query). The _f_e_t_c_h_m_a_i_l code tries to compensate by using POP3's UID feature, storing the identifiers of messages seen in each session until the next session, in the ._f_e_t_c_h_i_d_s file. But this doesn't track messages seen with other clients, or read directly with a mailer on the host but not deleted afterward. A better solution would be to switch to IMAP. Another 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 _f_e_t_c_h_m_a_i_l 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. The only real fix for this problem is to switch to IMAP. The IMAP code uses the presence or absence of the server flag \Seen to decide whether or not a message is new. 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 Page 12 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) look new to the server. In this (unlikely) case, only messages you fetched with _f_e_t_c_h_m_a_i_l --_k_e_e_p will be both undeleted and marked old. In ETRN mode, _f_e_t_c_h_m_a_i_l 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. SSSSPPPPAAAAMMMM FFFFIIIILLLLTTTTEEEERRRRIIIINNNNGGGG 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. Newer versions of _s_e_n_d_m_a_i_l return an error code of 571. This return value is blessed by RFC1893 as "Delivery not authorized, message refused". 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]."). The _e_x_i_m MTA returns 501 "Syntax error in parameters or arguments" , but will move to 550 soon. The _f_e_t_c_h_m_a_i_l code recognizes any of these error codes and discards the message. This is the _o_n_l_y circumstance under which fetchmail ever discards mail. If _f_e_t_c_h_m_a_i_l 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. TTTTHHHHEEEE RRRRUUUUNNNN CCCCOOOONNNNTTTTRRRROOOOLLLL FFFFIIIILLLLEEEE The preferred way to set up fetchmail is to write a ._f_e_t_c_h_m_a_i_l_r_c 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. To protect the security of your passwords, when --version is not on your ~/._f_e_t_c_h_m_a_i_l_r_c may not have more than 0600 (u=rw,g=,o=) permissions; _f_e_t_c_h_m_a_i_l will complain and exit otherwise. Page 13 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) You may read the ._f_e_t_c_h_m_a_i_l_r_c file as a list of commands to be executed when _f_e_t_c_h_m_a_i_l is called with no arguments. RRRRuuuunnnn CCCCoooonnnnttttrrrroooollll SSSSyyyynnnnttttaaaaxxxx 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). 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 standard C-style escapes (\n, \t, \b, octal, and hex) to embed non-printable characters or string delimiters in strings. 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. Note: the most common cause of syntax errors is mixing up user and server options. 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. PPPPoooollllllll vvvvssss.... SSSSkkkkiiiipppp The `poll' verb tells fetchmail to query this host when it is run with no arguments. The `skip' verb tells _f_e_t_c_h_m_a_i_l 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.) KKKKeeeeyyyywwwwoooorrrrdddd////OOOOppppttttiiiioooonnnn SSSSuuuummmmmmmmaaaarrrryyyy 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. Keyword Opt Function Page 14 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) _________________________________________________________ via Specify DNS name of mailserver, overriding poll name proto[col] -p Specify protocol (case insensitive): POP2, POP3, IMAP, IMAP-K4, APOP, KPOP port -P Specify TCP/IP service port auth[enticate] -A Set preauthentication type (default `password') timeout -t Server inactivity timout in seconds (default 300) envelope -E Specify envelope-address header name no envelope Disable looking for envelope address qvirtual -Q Qmail virtual domain prefix to remove from user name aka 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 dns Enable DNS lookup for multidrop (default) no dns Disable DNS lookup for multidrop uidl -U Force POP3 to use client-side UIDLs no uidl Turn off POP3 use of client-side UIDLs (default) Here are the legal user options: K_e_y_w_o_r_d__________O_p_t____F_u_n_c_t_i_o_n___________________________ user[name] -u Set remote user name (local user name if name followed by `here') is Connect local and remote user names to Connect local and remote user names pass[word] Specify remote account password folder -r Specify remote folder to query smtphost -S Specify smtp host(s) to forward to mda -m Specify MDA for local delivery preconnect Command to be executed before each connection postconnect Command to be executed after each connection keep -k Don't delete seen messages from Page 15 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) server flush -F Flush all seen 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 lines out of incoming mail 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) limit -l Set message size limit batchlimit -b Max # messages to fetch in single connect fetchlimit -B Max # messages to forward in single connect expunge -e Perform an expunge on every #th message (IMAP only) syslog Do error logging through syslog(3). Remember that all user options must _f_o_l_l_o_w all server 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 (that is, an argument of 1 selects the second header of the given type). This is sometime useful for ignoring bogus Received headers created by an ISP's local delivery agent. KKKKeeeeyyyywwwwoooorrrrddddssss NNNNooootttt CCCCoooorrrrrrrreeeessssppppoooonnnnddddiiiinnnngggg TTTToooo OOOOppppttttiiiioooonnnn SSSSwwwwiiiittttcccchhhheeeessss The `folder' and `smtphost' options (unlike their command- Page 16 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 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', `password', `preconnect', `postconnect', `localdomains', `stripcr'/`no stripcr', `forcecr'/`no forcecr', `pass8bits'/`no pass8bits' `dropstatus/no dropstatus', and `no envelope'. 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. 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. 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. 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 _f_e_t_c_h_m_a_i_l never does DNS lookups. When there is more than one local name (or name mapping) the _f_e_t_c_h_m_a_i_l 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 _f_e_t_c_h_m_a_i_l cannot match any mailserver usernames or localdomain addresses, the default recipient is the calling user. Page 17 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 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. 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 _f_e_t_c_h_m_a_i_l, 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. 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 _n_o_t applied). If you are using `localdomains', you may also need to specify `no envelope', which disables _f_e_t_c_h_m_a_i_l'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 ppppaaaasssssssswwwwoooorrrrdddd 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 _f_e_t_c_h_m_a_i_l establishes a mailserver connection. This may be useful if you are attempting to set up secure POP connections with the aid of _s_s_h(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). Page 18 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 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, _f_e_t_c_h_m_a_i_l 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, _f_e_t_c_h_m_a_i_l 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 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.) MMMMiiiisssscccceeeellllllllaaaannnneeeeoooouuuussss RRRRuuuunnnn CCCCoooonnnnttttrrrroooollll OOOOppppttttiiiioooonnnnssss 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) pop2 (or POP2) pop3 (or POP3) imap (or IMAP) imap-k4 (or IMAP-K4) apop (or APOP) kpop (or KPOP) Legal authentication types are `password' or `kerberos'. The former specifies authentication by normal transmission of a password (the password may be plaintext or subject to Page 19 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) protocol-specific encryption as in APOP); the second tells _f_e_t_c_h_m_a_i_l to try to get a Kerberos ticket at the start of each query instead, and send an arbitrary string as the password. Specifying `kpop' sets POP3 protocol over port 1109 with Kerberos V4 preauthentication. These defaults may be overridden by later options. 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). CCCCOOOONNNNFFFFIIIIGGGGUUUURRRRAAAATTTTIIIIOOOONNNN EEEEXXXXAAAAMMMMPPPPLLLLEEEESSSS 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 a version of those two 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; This version is much easier to read and doesn't cost significantly more (parsing is done only once, at startup time). If you need to include whitespace in a parameter string, enclose the string in double quotes. Thus: Page 20 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) poll mail.provider.net with proto pop3: user jsmith there has password "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 (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 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 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'. Here's what a simple retrieval configuration for a multi- drop 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 multi-drop 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'. Here's an example of another kind of multidrop connection: poll pop.provider.net localdomains loonytoons.org: user maildrop with pass secret1 to esr * here This also says that the mailbox of account `maildrop' on the server is a multi-drop box. It tells fetchmail that any Page 21 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 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! 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. 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"; TTTTHHHHEEEE UUUUSSSSEEEE AAAANNNNDDDD AAAABBBBUUUUSSSSEEEE OOOOFFFF MMMMUUUULLLLTTTTIIIIDDDDRRRROOOOPPPP Use the multiple-local-recipients feature with caution -- it can bite. Also note that all multidrop features are ineffective in ETRN mode. HHHHeeeeaaaaddddeeeerrrr vvvvssss.... EEEEnnnnvvvveeeellllooooppppeeee aaaaddddddddrrrreeeesssssssseeeessss 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. Sometimes _f_e_t_c_h_m_a_i_l can deduce the envelope address. If the mailserver MTA is _s_e_n_d_m_a_i_l 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, _f_e_t_c_h_m_a_i_l looks for envelope addresses in these lines; you can restore this default with -E "Received" or `envelope Received'. 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. A slight variation of the `X-Envelope-To' header is the `Delivered-To' put by qmail to avoid mail loops. It will probably prefix the user name with a string that normally matches the user's domain. To remove this prefix you can use Page 22 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) the -Q or `qvirtual' option. Sometimes, unfortunately, neither of these methods works. When they all 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. When _f_e_t_c_h_m_a_i_l 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. A related problem is that when you blind-copy a mail message, the Bcc information is carried _o_n_l_y 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. GGGGoooooooodddd WWWWaaaayyyyssss TTTToooo UUUUsssseeee MMMMuuuullllttttiiiiddddrrrroooopppp MMMMaaaaiiiillllbbbbooooxxxxeeeessss Multiple local names can be used to administer a mailing list from the client side of a _f_e_t_c_h_m_a_i_l 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 ._f_e_t_c_h_m_a_i_l_r_c, 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 _n_o_t 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 _f_e_t_c_h_m_a_i_l, but the program has no way Page 23 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) to know that that's actually the right thing. BBBBaaaadddd WWWWaaaayyyyssss TTTToooo AAAAbbbbuuuusssseeee MMMMuuuullllttttiiiiddddrrrroooopppp MMMMaaaaiiiillllbbbbooooxxxxeeeessss Multidrop mailboxes and _f_e_t_c_h_m_a_i_l 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 _f_e_t_c_h_m_a_i_l 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 _f_e_t_c_h_m_a_i_l 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. If you absolutely _m_u_s_t use multidrop for this purpose, make sure your mailserver writes an envelope-address header that fetchmail can see. Otherwise you _w_i_l_l lose mail and it _w_i_l_l come back to haunt you. SSSSppppeeeeeeeeddddiiiinnnngggg UUUUpppp MMMMuuuullllttttiiiiddddrrrroooopppp CCCChhhheeeecccckkkkiiiinnnngggg Normally, when multiple user are declared _f_e_t_c_h_m_a_i_l 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 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 aaaallllllll DNS aliases of the mailserver (and all MX names pointing at it) you can declare `no dns' to suppress DNS lookups entirely and _o_n_l_y match against the aka list. EEEEXXXXIIIITTTT CCCCOOOODDDDEEEESSSS To facilitate the use of _f_e_t_c_h_m_a_i_l in shell scripts, an exit code is returned to give an indication of what occurred during a given connection. The exit codes returned by _f_e_t_c_h_m_a_i_l are as follows: 0 One or more messages were successfully retrieved. Page 24 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) 1 There was no mail awaiting retrieval. (There may have been old mail still on the server but not selected for retrieval.) 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 -- just treat this as an 'unrecoverable error'. 3 The user authentication step failed. This usually means that a bad user-id, password, or APOP id was specified. 4 Some sort of fatal protocol error was detected. 5 There was a syntax error in the arguments to _f_e_t_c_h_m_a_i_l. 6 The run control file had bad permissions. 7 There was an error condition reported by the server. Can also fire if _f_e_t_c_h_m_a_i_l timed out while waiting for the server. 8 Client-side exclusion error. This means _f_e_t_c_h_m_a_i_l 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 _f_e_t_c_h_m_a_i_l. 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. 11 Internal error. You should see a message on standard error with details. When _f_e_t_c_h_m_a_i_l queries more than one host, return status is 0 if _a_n_y query successfully retrieved mail. Otherwise the returned error status is that of the last host queried. Page 25 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) AAAAUUUUTTTTHHHHOOOORRRR Eric S. Raymond <esr@snark.thyrsus.com>. This program is descended from and replaces _p_o_p_c_l_i_e_n_t, by Carl Harris <ceharris@mal.com>; the internals are quite different, but some of its interface design is directly traceable to that ancestral program. FFFFIIIILLLLEEEESSSS ~/.fetchmailrc default run control file ~/.fetchids default location of file associating hosts with last message IDs seen (used only with newer RFC1725- compliant POP3 servers supporting the UIDL command). ~/.netrc your FTP run control file, which (if present) will be searched for passwords as a last resort before prompting for one interactively. ~/.fetchmail lock file to help prevent concurrent runs (non-root mode). /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). EEEENNNNVVVVIIIIRRRROOOONNNNMMMMEEEENNNNTTTT For correct initialization, _f_e_t_c_h_m_a_i_l requires either that both the USER and HOME environment variables are correctly set, or that ggggeeeettttppppwwwwuuuuiiiidddd(3) be able to retrieve a password entry from your user ID. SSSSIIIIGGGGNNNNAAAALLLLSSSS If a _f_e_t_c_h_m_a_i_l 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). If _f_e_t_c_h_m_a_i_l 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). Page 26 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) Running _f_e_t_c_h_m_a_i_l in foreground while a background fetchmail is running will do whichever of these is appropriate to wake it up. BBBBUUUUGGGGSSSS AAAANNNNDDDD KKKKNNNNOOOOWWWWNNNN PPPPRRRROOOOBBBBLLLLEEEEMMMMSSSS 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. 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. Send comments, bug reports, gripes, and the like to Eric S. Raymond <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. SSSSEEEEEEEE AAAALLLLSSSSOOOO elm(1), mail(1), sendmail(8), popd(8), imapd(8) AAAAPPPPPPPPLLLLIIIICCCCAAAABBBBLLLLEEEE SSSSTTTTAAAANNNNDDDDAAAARRRRDDDDSSSS SMTP/ESMTP: RFC 821, RFC 1869, RFC 1652, RFC 1870, RFC1983, RFC 1985 mail: RFC 822 POP2: RFC 937 POP3: RFC 1081, RFC 1225, RFC 1460, RFC 1725, RFC 1939 APOP: RFC 1460, RFC 1725, RFC 1939 RPOP: Page 27 (printed 6/9/98) ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) UUUUNNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV ffffeeeettttcccchhhhmmmmaaaaiiiillll((((1111)))) RFC 1081, RFC 1225 IMAP2/IMAP2BIS: RFC 1176, RFC 1732 IMAP4: RFC 1730, RFC 1731, RFC 1732, RFC 2060, RFC 2061 ETRN: RFC 1985 OTP: RFC 1938 Page 28 (printed 6/9/98)