.\" Copyright 1993-95 by Carl Harris, Jr. Copyright 1996 by Eric S. Raymond .\" All rights reserved. .\" For license terms, see the file COPYING in this directory. .TH fetchmail LOCAL .SH NAME fetchmail \- deliver mail fetched from a POP or IMAP server .SH SYNOPSIS .B fetchmail [\fI options \fR] \fI [server-host...]\fR .SH DESCRIPTION .I fetchmail is a batch mail-retrieval/forwarding utility intended to be used over on-demand TCP/IP links (such as SLIP or PPP connections). It fetches mail from remote mail servers 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 \fIelm\fR(1) or \fIMail\fR(1). The \fBfetchmail\fR utility can be run in a daemon mode to repeatedly poll one or more systems at a specified interval. .PP 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 1725), IMAP2bis (as implemented by the 4.4BSD imapd program), and IMAP4 (as specified by RFC1730). It can use (but does not require) the RPOP and LAST facilities removed from later POP3 versions. .PP As each message is retrieved \fIfetchmail\fR 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 \fI/usr/lib/sendmail\fR 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. .PP The behavior of .I fetchmail is controlled by command-line options and a run control file, \fI~/.fetchmailrc\fR, the syntax of which we describe below. Command-line options override .I ~/.fetchmailrc declarations. .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. .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, and POP3 retrieval on servers without the LAST command, behaves as though --all is always on (see RETRIEVAL FAILURE MODES below). .TP .B \-S host, --smtphost host Specify an 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 (this can be useful if you don't want to run sendmail as an SMTP listener for security or other reasons). Some possible MDAs are "/usr/sbin/sendmail -oem %s", "/usr/lib/sendmail -oem %s", "/usr/formail", and "/usr/bin/deliver %s" (if the MDA command contains %s, that escape will be expanded into your username on the client machine). .TP .B \-F, --flush POP3/IMAP only. Delete old (previously retrieved) messages from the mailserver before retrieving new messages. .TP .B \-f pathname, --fetchmailrc pathname Specify a non-default name for the .I .fetchmailrc run control file. .TP .B \-k, --keep Keep retrieved messages in folder on 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. .TP .B \-K, --kill 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. .TP .B \-p, \--protocol proto Specify the protocol to used when communicating with the remote mailserver. If no protocol is specified, .I fetchmail will try each of the supported protocols in turn, terminating after any successful attempt. .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 POP3 with \fI.rhosts\fR processing (not recommended). .RE .TP .B \-P, --port The option permits you to specify a TCP/IP port to connect on. You will need to specify this in order to use RPOP authentication. Otherwise this option will seldom be necessary as all the supported protocols have well-established default port numbers. .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. .TP .B \-s, --silent Silent mode. Suppresses all progress/status messages that are normally echoed to stderr during a fetch. If both the .B silent and .B verbose options are specified, the .B verbose option takes precedence. .TP .B \-u name, --username name Specifies the user idenfication 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 machine that is running .I fetchmail. See USER AUTHENTICATION below for a complete description. .TP .B \-v, --verbose Verbose mode. All control messages passed between .I fetchmail and the mailserver are echoed to stderr. Specifying .B verbose causes normal progress/status messages which would be redundant or meaningless to be modified or omitted. .TP .B \-N, --norewrite Normally, .I fetchmail edits RFC-822 address headers (To, From, Cc, Bcc, and Reply-To) in fetched mail so that any mail IDs local to the server are expanded to full addresses (@ and the mail server 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. .TP .B \-V, --version Displays the version information for your copy of .I fetchmail. No POP connection is made. Instead, for each server specified, all option information that would be computed if .I fetchmail. were connecting to that server is displayed. .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. .SH USER AUTHENTICATION User authentication in .I fetchmail is very much like the authentication mechanism of .I ftp(1). The correct user-id and password depend upon the underlying security system at the mailserver. .PP If the mailserver is a Unix machine on which you have an ordinary user account, your regular login name and password are used with .I fetchmail. If you use the same login name on both the server and the client machines, you needn't worry about specifying a user-id with the .B \-u option \-\- the default behavior is to use your login name on the client machine as the user-id on the server machine. If you use a different login name on the server machine, specify that login name with the .B \-u option. e.g. if your login name is 'jsmith' on a machine named 'mailgrunt', you would start .I fetchmail as follows: .IP fetchmail -u jsmith mailgrunt .PP The default behavior of .I fetchmail is to prompt you for your mailserver password before the connection is established. This is the safest way to use .I fetchmail and ensures that your password will not be compromised. You may also specify your password in your .I ~/.fetchmailrc file. This is convenient when using .I fetchmail in daemon mode or with scripts. .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 POP3 versions up to the RFC1225 version supported an alternate authentication mechanism called RPOP intended to address the security risk inherent in sending unencrypted account passwords across the net (in RFC1460 this facility was replaced with APOP). If you specify the RPOP protocol and a connection port in the privileged range (1..1024), .I fetchmail will ship your password entry to the mail server as an RPOP id. (Note: you'll need to be running fetchmail setuid root for RPOP to work -- .I fetchmail has to bind to a privileged port locally in order for the mail server to believe it's allowed to bind to a privileged remote port.) .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 put the same password in your .I .fetchmailrc file. Each time .I fetchmail 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. .SH DAEMON MODE The .B --daemon or .B -d option runs .I fetchmail in daemon mode. You must specify a numeric argument which is a polling interval in seconds. .PP In daemon mode, .I fetchmail puts itself in background and runs forever, querying each specified host and then sleeping for the given polling interval. .PP Simply invoking .IP fetchmail -d 900 .PP will, therefore, poll the hosts described in your .I ~/.fetchmailrc file once every fifteen minutes. .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. .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). This is primarily useful for debugging configurations. .SH RETRIEVAL FAILURE MODES The protocols \fIfetchmail\fR uses to talk to mail servers 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 \fIfetchmail\fRthat 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). .PP The normal mode of \fIfetchmail\fR 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 \fIfetchmail --keep\fR). 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. .PP One could be that you're using POP2. The POP2 protocol includes no representation of `new' or `old' state in messages, so \fIfetchmail\fR must treat all messages as new all the time. POP2 is obsolete. .PP Under POP3, blame RFC1725. That late version of the POP3 protocol specification ill-advisedly removed the LAST command, and some POP servers (including the one distributed with at least some versions of SunOS) follow it (you can verify this by invoking \fIfetchmail -v\fR to the mail server and watching the response to LAST early in the query). The fix is to install an older POP3 server with LAST or (better) switch to an IMAP server. .PP 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 \fIfetchmail\fR 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. .PP The IMAP code uses the presence or absence of the server flag \eSeen 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 look new to the server. In this (unlikely) case, only messages you fetched with \fIfetchmail --keep\fR will be both undeleted and marked old. .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 u+r,u+w permissions; .I fetchmail will complain and exit otherwise. .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. Any amount of whitespace separates keywords, tokens, or strings in server entries but is otherwise ignored (but whitespace enclosed in double quotes is treated as part of the string). Keywords and identifiers are case sensitive. When there is a conflict between the command-line arguments and the arguments in this file, the command-line arguments take precedence. .PP Each server entry consists of the keyword \fBserver\fR, followed by a server name, followed by server options, followed by any number of user descriptions. .PP Legal server options are: server protocol (or proto) port skip noskip Legal user options are username (or user) is 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 three: \fBis\fR, \fBpassword\fR and \fBskip\fR. .PP The \fBis\fR keyword associates a following local username with the mailserver user name in the entry. It is intended to be used in configurations where \fIfetchmail\fR runs as root and retrieves mail for multiple local users. If no \fBis\fR clause is present, the default local username is the same as the argument of the \fBuser\fR keyword. .PP The \fBpassword\fR option requires a string argument, which is the password to be used with the entry's server. .PP The \fBskip\fR option tells .I fetchmail not to query this host unless it is explicitly named on the command line. A host entry with this flag will be skipped when .I fetchmail called with no arguments steps through all hosts in the run control file. (This option allows you to experiment with test entries safely, or easily disable entries for hosts that are temporarily down.) .PP Legal protocol identifiers are auto (or AUTO) pop2 (or POP2) pop3 (or POP3) imap (or IMAP) apop (or APOP) rpop (or RPOP) .PP You can use the `noise' keywords \fBand\fR, \fBwith\fR, \fBhas\fR, \fBwants\fR, and \fBoptions\fR 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 \fBhere\fR and \fBthere\fR also have useful English-like significance. Normally `\fBuser eric is esr\fR' would mean that mail for the remote user \fBeric\fR is to be delivered to \fBesr\fR, but you can make this clearer by saying `\fBuser eric there is esr here\fR', or reverse it by saying `\fBuser esr here is eric there\fR' .PP Finally, instead of saying `\fBserver fubar.com skip\fR ...' you can say \&`\fBskip server fubar.com\fR ...' .PP Basic format is: .nf server SERVERNAME protocol PROTOCOL username NAME password PASSWORD .fi .PP Example: .nf server pop.provider.net protocol pop3 username jsmith password secret1 .fi .PP Or, using some abbreviations: .nf server pop.provider.net proto pop3 user jsmith password secret1 .fi .PP Multiple servers may be listed: .nf server pop.provider.net proto pop3 user jsmith pass secret1 server other.provider.net proto pop2 user John.Smith pass My^Hat .fi Here's a version of those two with more whitespace and some noise words: .nf server pop.provider.net proto pop3 user jsmith, with password secret1, is jsmith here; server other.provider.net proto pop2: user John.Smith with password My^Hat, is John.Smith here; .fi This version is much easier to read and doesn't cost significantly more (parsing is done only once, at startup time). .PP If you need to include whitespace in a parameter string, enclose the string in double quotes. Thus: .nf server mail.provider.net with proto pop3 user jsmith there has password "u can't krak this" is jws here and wants mda "/bin/mail %s" .fi You may have an initial server description headed by the keyword `defaults' instead of `server' 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: .nf defaults proto pop3 user jsmith server pop.provider.net pass secret1 server mail.provider.net user jjsmith there has password secret2 .fi 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 \fBuser\fR keyword leads off a user description, and every user description except optionally the first one must include it. (If the first description lacks the \fBuser\fR keyword, the name of the invoking user is used .) Here's a contrived example: .nf server 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 \fBpass gumshoe\fR 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 \fBuser\fR clause when specifying nultiple users for server. .SH EXIT CODES To facilitate the use of .I fetchmail in shell scripts, an exit code is returned to give an indication of what occurred during a given connection. .PP The exit codes returned by .I fetchmail are as follows: .IP 0 One or more messages were successfully retrieved. .IP 1 There was no mail awaiting 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 -- just treat this as an 'unrecoverable error'. .IP 3 The user authentication step failed. This usually means that a bad user-id, password, or RPOP id was specified. .IP 4 Some sort of fatal protocol error was detected. .IP 5 There was a syntax error in the arguments to .I fetchmail. .IP 6 The run control file had bad permissions. .IP 7 There was an error condition reported by the server (POP3 only). .IP 8 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 .I fetchmail. run failed while trying to do an SMTP port open or transaction. .IP 10 Something totally undefined occured. This is usually caused by a bug within .I fetchmail. Do let me know if this happens. .PP When .I fetchmail queries more than one host, the returned status is that of the last host queried. .SH AUTHORS .I fetchmail was originated (under the name `popclient') by Carl Harris at Virginia Polytechnic Institute and State University (a.k.a. Virginia Tech). .PP Version 3.0 of popclient was extensively rewritten and improved by Eric S. Raymond . The program's name was then changed to .I fetchmail to reflect both the presence of IMAP support and the symmetry with sendmail created by the new SMTP forwarding default. .PP .SH FILES .TP 5 ~/.fetchmailrc default run control file .TP 5 ${TMPDIR}/fetchmail-${HOST}-${USER} lock file to help prevent concurrent runs. .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 BUGS AND KNOWN PROBLEMS Use of any of the supported protocols other than APOP requires that the program send unencrypted passwords over the TCP/IP connection to the mail server. This creates a risk that name/password pairs might be snaffled with a packet sniffer or more sophisticated monitoring software. .PP The RPOP support is not yet well tested. .PP Send comments, bug reports, gripes, and the like to Eric S. Raymond . .SH NOTES This program used to be called `popclient' (the name was changed because it supports IMAP now and may well support more remote-fetch protocols such as DMSP in the future). If called through a link named popclient, it will look in ~/.poprc for its run control file. As long as the file does not use the removed \fBlimit\fR or \fBlocalfolder\fR options, this will often work. (The new run control file syntax also has to be a bit stricter about the order of options than the old, in order to support multiple user desriptions per server; you may have to rearrange things a bit.) .PP The --stdout, --local, and --limit arguments of previous versions have been removed. Those features did jobs that belonged to your local MDA and mail reader. The job of .I fetchmail is to forward local mail to your MDA, not to be one. Saint-Exupery said, "Perfection [in design] is achieved not when there is nothing more to add, but rather when there is nothing more to take away." This program isn't perfect, but it's trying. .PP The --password option of previous (popclient) versions has been removed -- it encouraged people to expose passwords in scripts. Passwords must now be specified either interactively or in your .I ~/.fetchmailrc file. The short-form -p option now specifies the protocol to use. .PP The reason the password isn't stored encrypted is because this doesn't actually add protection. Anyone who's acquired permissions to read your fetchmailrc file will be able to run .I fetchmail as you anyway -- and if it's your password they're after, they'd be able to use the necessary decoder from .I fetchmail itself to get it. All encryption would do in this context is give a false sense of security to people who don't think very hard. .SH SEE ALSO mail(1), binmail(1), sendmail(8), popd(8), imapd(8) RFC 937, RFC 1081, RFC 1082, RFC1176, RFC 1225, RFC 1460, RFC 1725.