
   #Charles Cazabon's Pages

getmail Frequently Asked Questions (FAQ)

   These  are  the  Frequently  Asked  Questions  about  getmail. If your
   question  is  not  answered  here  or  in  the  documentation,  please
   subscribe to the mailing list.

About this document

   The official location of this document is
   http://www.qcc.ca/~charlesc/software/getmail-3.0/docs.html.  For  easy
   navigation,  all  headings  in  the  HTML version of this document are
   links to their parent heading.

Table of Contents

    1. About getmail
    2. Error messages
    3. getmail configuration
    4. Other errors
    5. How do I ...

About getmail

What is getmail?

   getmail  is  a POP3 mail retriever, with support for both ordinary and
   domain  (or  multidrop)  POP3  mailboxes. It is written in Python, and
   licensed under the GNU General Public License version 2.

Why did you write getmail? Why not just use fetchmail?

   I  do  not  like  some  of  the  design  choices  which were made with
   fetchmail.  getmail  does  things  a  little  differently,  and for my
   purposes,  better.  In  addition,  most  people find getmail easier to
   configure  and  use  than fetchmail. Perhaps most importantly, getmail
   goes  to  great  lengths  to  ensure  that  mail  is never lost, while
   fetchmail (in its default configuration) frequently loses mail, causes
   mail  loops,  bounces  legitimate  messages,  and  causes  many  other
   problems.

   In addition, fetchmail has a long history of security problems:
     * versions  released  before 20 June 2001 contain a buffer overflow,
       which can be remotely exploited (see
       www.securityfocus.com/bid/2877   for   details).  getmail  is  not
       vulnerable  to  buffer  overflows,  because  buffers in Python are
       dynamically sized.
     * Another remotely-exploitable security hole discovered in fetchmail
       in June 2002; versions prior to 5.9.10 (released in June 2002) are
       exploitable.
     * Reading fetchmail's UPDATES file, it appears that another security
       problem  was fixed in 5.9.12, where a server could crash fetchmail
       on 64-bit platforms. Also worrying is a mention that it includes a
       fix for "password shrouding".
     * Another remotely-exploitable security hole in fetchmail discovered
       in  September  2002; this hole lets an attacker run arbitrary code
       on the victim's computer.
     * Another remotely-exploitable security hole in fetchmail discovered
       in  December 2002; once again, a remote attacker can run arbitrary
       code   on   the   machine   running   fetchmail   in  its  default
       configuration. See this advisory for details.
     * January 2003: More buffer overflows in fetchmail let attackers run
       arbitrary code.

   I've  given  up  even  trying  to stay abreast of the various security
   holes in fetchmail.

   But don't just take my word for it.

   getmail users have not had to worry about any of these security holes.

How can I get support for getmail?

   getmail is Free Software. As such, it comes with no warranty. However,
   I  will do my best to support getmail on a voluntary basis through the
   getmail mailing list.

   If  you  are  using getmail in a commercial or other environment where
   problems  cost  money, consider contacting me privately for commercial
   support.

   If  you  have  questions  about getmail, the first step is to read the
   documentation, and the remainder of the Frequently Asked Questions. If
   your  question  isn't  answered there, search the getmail mailing list
   archives at http://marc.theaimsgroup.com/?l=getmail&r=1&w=2.

   If  you  still  haven't  found  an  answer  to  your  question, please
   subscribe   to   the   mailing  list  by  sending  a  blank  email  to
   <getmail-subscribe   @   discworld.dnsalias.org>.  If  you  post  your
   question  there,  I will see it. As an additional bonus, your question
   may be answered by another member of the list.

I think I found a bug! How do I report it?

   Ideally, you should join the mailing list. Send your bug report there.
   You should include the following information:
     * getmail version
     * Python version
     * any error message which getmail displayed
     * the  output  from  running  getmail  with your normal options plus
       --dump
     * if  your  problem  is  getmail  not  determining  the proper local
       recipient,  please include the output of running getmail with your
       normal   options  plus  --trace,  showing  the  retrieval  of  one
       problematic message.

   If you absolutely cannot sign up for the mailing list, send the report
   to me directly. I may not be able to respond to all reports privately,
   but I will try to address any bugs I find out about this way.

Does getmail support virus scanning of retrieved messages?

   Yes,  getmail  can  use  external MDAs which do absolutely any type of
   message  scanning, filtering, etc. Also see this question about how to
   do this.

Does getmail rewrite mail headers when it retrieves mail?

   No--rewriting  message  header  fields  is bad. getmail will add a new
   Received:  header field and a new Delivered-To: header field, but does
   not  rewrite  existing  headers. You can disable the creation of these
   header fields.

How does getmail decide what local recipients to deliver a message to?

   This is a two-step process.
    1. getmail  first  tries  to  find  who  the  message  was originally
       addressed to using one of two methods:
          + If  you have enabled SPDS *ENV support, getmail will retrieve
            the  original  envelope  of  the message from an SPDS-enabled
            server (i.e. Demon provides this).
          + Envelope  recipient address method. If the MTA running on the
            POP3  servers  is  sensible,  it  will  record  the  envelope
            recipient  address  in  a  new header field at the top of the
            message.  You  can  then  tell  getmail  to find it using the
            envelope_recipient directive.
    2. getmail  will  then  compare  each  address  found  above  to  any
       configured local recipient address patterns. If a pattern matches,
       getmail  will  deliver  the message to that target. If no patterns
       match,  or  if  you have not configured getmail to reconstruct the
       original  envelope,  the  message  is  delivered  to  the  default
       delivery instruction (postmaster directive).

Error Messages

getmail fails with a message "AttributeError: 'module' object has no
attribute 'fsync'

   This  is  not  a  problem  with getmail; it is a well-known bug in the
   Python  2.3.1  distribution.  Downgrade  to  Python  version  2.3.0 or
   before, or upgrade to 2.3.2, which should fix the problem.

getmail complains about "incomplete format string" ...

   Double  any  percent  signs  you have in your getmailrc file--i.e., if
   your password is foo%bar, then actually specify it as foo%%bar.

getmail complains about "error in getmailrc file (expected option value, got
... )"

   You  have  a  syntax error in your getmailrc file. Empty option values
   are  not  allowed. If you want to specify an empty string as an option
   value, you have to quote it:
foo = ""

getmail complains about "configuration error in getmailrc file
(/path/to/getmailrc): file is group- or world-writable". What's wrong?

   Your  getmailrc  configuration  file  is group- or world-writable. For
   security   reasons,   getmail   refuses   to  run  with  a  group-  or
   world-writable getmailrc file. Change the permissions on that file.

getmail complains about "Configuration error (local directives require
use_*env or envelope_recipient to identify envelope recipient)". What's
wrong?

   The  account  configuration in question contains local directives, but
   you  haven't  told  getmail  how  to  determine  the original envelope
   recipient  address  of  the  message.  To use multidrop mode, you must
   either  enable use_*env (if your mailhost supports it) or tell getmail
   which  header  field  the envelope recipient address is recorded in by
   the mailhost's MTA using the envelope_recipient directive.

getmail complains about "Delivery error (refuse to deliver to commands as
root)". What's wrong?

   You're  running  getmail  as  user  "root"  (UID 0) and trying to have
   getmail run an external command. The documentation says don't do that.

getmail configuration

What is a "domain mailbox"?

   A  domain (or multidrop) mailbox is a POP3 mailbox which receives mail
   for  all  users in a given domain. Normal mailboxes contain mail for a
   single  user (like jason@myisp.co.uk); some Internet Service Providers
   which provide webhosting or other services will provide a POP3 mailbox
   which receives mail for all addresses in a given domain (i.e. mail for
   service@smallcompany.net,  sales@smallcompany.net, and indeed anything
   @smallcompany.net ends up in the same POP3 mailbox).

   getmail provides a method of retrieving mail from a domain mailbox and
   distributing  it  among  the  various  users  automatically.  See  the
   documentation  sections  on  header  field  pattern  matching delivery
   targets,  envelope  recipient  address  field  specification,  default
   delivery target, and POP3 domain mailboxes.

Do I have to run sendmail or another MTA to use getmail?

   No.  getmail  delivers directly to Maildirs or via arbitrary MDAs, and
   never  injects  mail  via SMTP, so no MTA is necessary. P.S. If you're
   currently  running sendmail, consider switching to qmail if you need a
   full  MTA, or nullmailer if you relay all your mail through your ISP's
   smarthost. Both of them are better and more secure than sendmail.

I've got a simple POP3 account. Do I need "local=..." configuration
variables?

   No, you don't need them. They might be useful to you if the MTA on the
   POP3  server supports extension addresses (i.e. qmail) and records the
   envelope  recipient  address  properly.  But in general, you will only
   need to use a postmaster directive.

Other getmail errors

I've configured getmail to deliver to my Maildir, but it won't do it. Why?

   Double-check  your  getmailrc  file.  Maildir  delivery  targets  must
   include a trailing slash.

I've configured getmail to deliver to my mbox file, but it won't do it. Why?

   getmail  3.x  does  not  have native mbox support, as all mbox-capable
   MDAs on a given system must use the same locking mechanism and support
   the  same  mbox  subtype.  You  can  use  getmail's  command  delivery
   mechanism  to deliver through an external mbox-aware MDA (see the next
   paragraph) if you must, but consider using maildirs instead.

   getmail  includes  getmail_mbox, an mbox delivery agent you can use in
   this   fashion.   It   supports  mboxrd-format  mbox  files  and  uses
   flock-style  locking.  Make  sure these are the correct types for your
   system before using it, as all mbox-handling programs on a system must
   use the same types and values.

   To  use  getmail_mbox  to  deliver  to  mbox  files,  specify it as an
   external  MDA.  It  takes  the  path to the mbox file as a commandline
   argument, as follows:
getmail_mbox /path/to/mbox

   Example uses:
postmaster = "|/path/to/getmail_mbox /path/to/mbox"
local = "^joe@.*$,|/path/to/getmail_mbox /home/joe/mbox"
local = "^sam@.*$,|/path/to/getmail_mbox /home/sam/mbox"

I've configured getmail to deliver to a command (external MDA), but it
complains that the command exited 0 but wrote to stderr. Why?

   Command  deliveries must exit 0 and not write anything to stderr to be
   considered  a  successful  delivery. If you know your MDA can write to
   stderr  on success, give your command a --quiet option (if it supports
   it)  or discard or redirect stderr in the command specification of the
   delivery target.

Why does getmail retrieve all my messages when I've told it to only retrieve
new mail?

   Your  POP3  mail  server is probably broken. getmail requires that the
   server support the POP3 UIDL command to uniquely identify messages. If
   the  server  doesn't support it, getmail cannot tell which messages it
   has already seen, and therefore retrieves all messages.

How do I ...

How do I stop getmail adding a Delivered-To: header to email?

   Use the no_delivered_to configuration directive.

How do I stop getmail adding a Received: header to email?

   Use the no_received configuration directive.

How do I make getmail deliver messages to a program?

   Specify  the  delivery target as |path-to-command. You should probably
   use   full   paths  (e.g.  /usr/bin/maildrop).  As  a  basic  security
   precaution,  getmail  will  refuse  to  deliver  to  programs if it is
   running as root.

   Warning:  if  you don't know what you're doing, you can shoot yourself
   in the foot with this option.

How do I make getmail deliver messages by re-injecting with SMTP?

   You  don't. getmail doesn't do this, to prevent lost mail, mail loops,
   and  bounces  if getmail or your Mail Transfer Agent is misconfigured.
   getmail  has native support for delivering to qmail-style Maildirs and
   commands  (pipe  delivery).  Therefore you shouldn't need to re-inject
   retrieved messages.

   If  you  absolutely  must inject retrieved messages into an MTA, it is
   possible  to  do  this  knowing  no  more than what is included in the
   getmail  documentation.  If  you  know  enough about mail to avoid the
   pitfalls mentioned above, you don't need my help figuring out how.

How do I make getmail use SSL / talk to an SSL-wrapped POP3 server (POP3S)?

   Use  the  SSL  utility  stunnel to set up an SSL tunnel from a port on
   your  machine to the SSL-wrapped POP3 port (typically TCP port 995) on
   the  mailserver. Then configure getmail to connect to the local end of
   the tunnel.

   The  easiest way to do this is to use a tiny shellscript wrapper which
   sets up the tunnel and then runs getmail. An example would be:
#!/bin/sh
/usr/sbin/stunnel -c -D 4 -d 8110 -r 192.168.2.3:995
getmail

   The  above script sets up a tunnel from port 8110 on localhost to port
   995 on the mailserver at 192.168.2.3. You would then use the following
   getmailrc configuration:
[SSL-wrapped access to my mail]
server = localhost
port = 8110
username = me
password = mypassword

   Note  that  there are security considerations with this configuration,
   as  with all configurations. For instance, do not configure getmail to
   connect  to a port that another local user might have already set up a
   listener on; stunnel could fail to set up the tunnel, and if the other
   user  had  set up a POP3 listener, getmail would send your credentials
   to  it.  You  could  set up the tunnel on a privileged port to prevent
   non-privileged local users from mounting this type of attack.

How do I run getmail in "daemon" mode?

   Use your system's cron utility to run getmail periodically if you wish
   to  have  mail retrieved automatically at intervals. This is precisely
   what  cron  is  designed to do; there's no need to add special code to
   getmail to do this.

How do I use TMDA with getmail?

   TMDA  is the Tagged Message Delivery Agent, an excercise in preventing
   spam from ever reaching your inbox.

   To make getmail export the environment variables which TMDA needs, you
   must  use  local  directives  in  your  getmailrc  file.  You can then
   optionally set the extension_sep and extension_depth directives.

   For  example,  if  getmail  determines  the  envelope  recipient to be
   domain-user-ext1-ext2@otherdomain.tld,  extension_sep is set to -, and
   extension_depth   is   set   to  1,  then  getmail  will  set  EXT  to
   user-ext1-ext2.  If  extension_depth  is 2, it will instead set EXT to
   ext1-ext2.

   TMDA    renames    existing    Delivered-To:    header    fields    to
   Old-Delivered-To:. Previous versions (0.55 through 0.57 or so) instead
   tried  to  strip  recent  Delivered-To:  fields  and may have required
   disabling getmail's addition of new Delivered-To: header fields.

   You  will  need  a  wrapper  around  TMDA to use in a command delivery
   target  which  conditionally delivers the message based on TMDA's exit
   code.  getmail does not include such a wrapper; you will need to write
   it or find it yourself.

   Note  that  getmail  will  only  be  able  to  determine  the envelope
   recipient address (and extension part of that address) reliably if the
   MTA  at the POP3 server is configured to record the envelope recipient
   in a message header field (i.e. as qmail does with Delivered-To:), and
   you have configured getmail to only look at that header field with the
   envelope_recipient  directive,  or  if your ISP supports the SPDS *ENV
   extension and you have configured getmail to use it.

   If  anyone  has  concrete  experience using getmail and TMDA together,
   please  feel free to send instructions or your wrapper script to me; I
   personally do not use a filtering MDA and therefore have no experience
   making TMDA work with getmail.

How do I do virus scanning of retrieved messages with getmail?

   You  can do this in hundreds of different ways. There are many threads
   in  the  mailing  list  archive  dealing specifically with this topic;
   please  read  at  least  all  of February 2003, including this thread,
   before posting to the mailing list.

How do I do message filtering with getmail?

   The  best  way is to use a program designed specifically to do message
   filtering, like a filtering MDA. The best-known example of a filtering
   MDA  is  procmail,  but  I  don't recommend using it. maildrop is much
   easier to use.

   getmail  can  invoke  arbitrary  programs as external MDAs, so you can
   also  write your own filters as you choose. A simple example, changing
   all  occurrences  of the string "stupid" to "XXXXXX" and using safecat
   to  deliver  the  resulting  filtered message to a Maildir might be to
   specify a delivery target of
|/bin/sed 's/stupid/XXXXXX/g' | safecat ./Maildir/tmp ./Maildir/new

   .
