HOWTO - Using exim and mailman together

Mailman is a list manager with web front end and built in archiving functions. Details can be found at http://www.list.org/

Mailman configuration

There is no mailman configuration needed other than the standard options detailed in the mailman install documentation. The exim configuration is transparent to mailman. The uid/gid settings for mailman must match those in the config fragments given below.

Exim configuration

The exim configuration is built so that a list created within mailman automagically appears to exim without the need for additional alias files etc to be changed.

The drawback of this configuration is that it will work poorly on systems supporting lists in several different mail domains - for that matter mailman itself has poor support for this right now. This may change in the future

The configuration file segments included are to be built on top of an already functional exim configuration, which accepts mail for the domain which the list resides in (ie that domain is already in local_domains - should this domain be separate from the others handled by this exim, then add the list domain to local_domains, add a domains=my.list.domain option to each of the directors and you may wish to exclude that domain from the other directors.

Your exim configuration also needs a working alias configuration, with entries (within the list domain) for mailman, mailman-request and mailman-admin (plus any other global contact addresses for the list master.

There are 3 config file sections below which need pasting into the appropriate parts of the main exim config file. The first one may also need tailoring to your mailman configuration

Main config file section

## Top section of config file - macro definitions
## Tailor these to fit your installation
## pretty much everything else should just fit...
##
# home dir for mailman
MAILMAN_HOME=/home/mailman
# wrapper script for mailman
MAILMAN_WRAP=MAILMAN_HOME/mail/wrapper
# user and group for mailman
MAILMAN_UID=exim
MAILMAN_GID=exim

Transports config file section

## Transports section
##
## Three transports for list mail, request mail and admin mail
## respectively
## Mailman is installed in MAILMAN_HOME
## Mailman is configured to be invoked as user exim
list_transport:
           driver = pipe
           command = MAILMAN_WRAP post ${lc:$local_part}
           current_directory = MAILMAN_HOME
           home_directory = MAILMAN_HOME
           user = MAILMAN_UID
           group = MAILMAN_GID

list_request_transport:
           driver = pipe
           command = MAILMAN_WRAP mailcmd ${lc:$local_part}
           current_directory = MAILMAN_HOME
           home_directory = MAILMAN_HOME
           user = MAILMAN_UID
           group = MAILMAN_GID

list_admin_transport:
           driver = pipe
           command = MAILMAN_WRAP mailowner ${lc:$local_part}
           current_directory = MAILMAN_HOME
           home_directory = MAILMAN_HOME
           user = MAILMAN_UID
           group = MAILMAN_GID

### end of transports section fragment

Directors config file section

## Directors section [this deals with local addresses]
## 
## First 2 directors rewrite list-owner or owner-list to list-admin
## This is only done if the list exists.
## List existence checks are done by seeing if the file
## MAILMAN_HOME/lists//config.db
## exists.  

list_owner_director:
   driver = smartuser
   require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
   suffix = "-owner"
   new_address = "${lc:$local_part}-admin@${domain}"

owner_list_director:
   driver = smartuser
   require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
   prefix = "owner-"
   new_address = "${lc:$local_part}-admin@${domain}"

##
## Next 3 directors direct admin, request and list mail to the appropriate
## transport.  List existence is checked as above.

list_admin_director:
   driver = smartuser
   suffix = -admin
   require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
   transport = list_admin_transport

list_request_director:
   driver = smartuser
   suffix = -request
   require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
   transport = list_request_transport

list_director:
   driver = smartuser
   require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
   transport = list_transport

## End of directors fragment
## End of config files bits

Exim should be configured to allow reasonable volume - ie no setting max_recipients down to a silly value, and with normal degrees of security - ie allowing relaying from 127.0.0.1 (thats vital), but pretty much nothing else. Parallel deliveries and other tweaks can also be used. Delay warning messages should be switched off or configured to only happen for non-list mail - unless you like receiving tons of mail when a host is down.

Problems

Mailman's detection of exim bounces needs improving - it really should make use of the extra header information that exim provides. It also should recognise and deal with or ignore delay warning messages.
List existence is checked on whether there is a config.db file for a list. If you delete lists by foul means, be aware of this.

Other Tweaks

One solution passed to me for handling virtual domains was - Since I use mailman in a virtual domain configuration with a separate installation for each virtual domain, I did a slight modification like this:

## transport configurations

command = "/virtual/${domain}/mailman/mail/wrapper post ${lc:$local_part}"
current_directory = /virtual/${domain}/mailman
home_directory = /virtual/${domain}/mailman

## and in the director part:

require_files = /virtual/${domain}/mailman/lists/${lc:$local_part}/config.db

Nigel Metheringham