Exim4 configuration

This is a step-by-step guide to run mlmmj with Exim4. The most current version
of this can be found on http://plonk.de/sw/mlmmj/README.exim4.

Notes:

• We assume that you have a user and group called mlmmj to use with mlmmj
• The exim user needs rx access rights to mlmmj's spool directory. (If you don't want that, see below.) The easiest way is "chmod 755 /path/to/mlmmj/spool", if it's ok that local users can see which lists there are. Note that the owner of the mlmmj spool must still be the mlmmj user (and this user must have at least x rights to the directories below).
• Existence of mailing lists is automatically checked ($listdir) and you don't need to put anything into your aliases file
• If you want VERP to be done by your MTA, follow the instructions below and put an empty file named verp into the control directory of your lists

1. In the main configuration section:
   

   MLMMJ_HOME=/var/spool/mlmmj
   domainlist mlmmj_domains = list.example.net
   

2. Add +mlmmj_domains to relay_to_domains:
   

   domainlist relay_to_domains = other.domain : +mlmmj_domains
   

3. mlmmj is barely interested in delay warnings, so add this in the main
   configuration:

   delay_warning_condition = ${if match_domain{$domain}{+mlmmj_domains}{no}{yes}}
   

4. In the routers section (before the dnslookup router, preferably at the
   beginning):

   mlmmj_router:
     driver = accept
     domains = +mlmmj_domains
     require_files = MLMMJ_HOME/${lc::$local_part}
     # Use this instead, if you don't want to give Exim rx rights to mlmmj spool.
     # Exim will then spawn a new process running under the UID of "mlmmj".
     #require_files = mlmmj:MLMMJ_HOME/${lc::$local_part}
     local_part_suffix = +*
     local_part_suffix_optional
     headers_remove = Delivered-To
     headers_add = Delivered-To: $local_part$local_part_suffix@$domain
     transport = mlmmj_transport
   

   If you want VERP to be done by your MTA, also add this:

   verp_router:
     driver = dnslookup
     domains = !+mlmmj_domains
     # we only consider messages sent in through loopback
     condition = ${if eq{$sender_host_address}{127.0.0.1}{yes}{no}}
     ignore_target_hosts = <; 0.0.0.0; 127.0.0.0/8; ::1/128; fe80::/10; ff00::/8
     # only the un-VERPed bounce addresses are handled
     senders = \N^.+\+bounces-\d+@.+\N
     transport = verp_smtp
   

   To prevent temporary errors for not-existing lists, add !+mlmmj_domains to the
   domains condition of the dnslookup router:

   dnslookup:
     driver = dnslookup
     domains = !+mlmmj_domains : !+local_domains
   [...]
   

5. Somewhere in the transports section. (Change the path of mlmmj-recieve if you
   don't use the default location!):

   mlmmj_transport:
     driver = pipe
     return_path_add
     user = mlmmj
     group = mlmmj
     home_directory = MLMMJ_HOME
     current_directory = MLMMJ_HOME
     command = /usr/local/bin/mlmmj-recieve -F -L MLMMJ_HOME/${lc:$local_part}
   

   If you want VERP to be done by your MTA, also add this:

   verp_smtp:
     driver = smtp
     # put recipient address into return_path
     return_path = ${quote_local_part:${local_part:$return_path}}-\
                   ${original_local_part}=${original_domain}@\
                   ${domain:$return_path}
     # must restrict to one recipient at a time
     max_rcpt = 1
     # Errors-To: may carry old return_path
     headers_remove = Errors-To
     headers_add = Errors-To: $return_path
   

6. Test your setup with
   

   $ exim -bt mlmmj-test@your.list.domain
   mlmmj-test@your.list.domain
     router = mlmmj_router, transport = mlmmj_transport
   

   If you get different output, run it with -d to see what's going wrong.
   If not, you're done!

   Jakob Hirsch (jh at plonk dot de)