Re: [Exim] central mx distributing to 10 Mail-Server

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Author: Steve Haslam
Date:  
To: Patrick von der Hagen
CC: exim-users
Subject: Re: [Exim] central mx distributing to 10 Mail-Server
On Tue, Dec 12, 2000 at 01:08:40AM +0100, Patrick von der Hagen wrote:

[Summary: advertised email address foo@domain is distributed by
mailhost.domain to mailhost.departmentX.domain]

> My first attempt is, to put it all in an alias-file.

[...]
> Of course I would get a 5000 lines alias-file.


Yes- think "map" rather than alias-file specifically, and you can use
LDAP, SQL... to publish the map.

> But using a hash-table, it would probably be ok... BTW, assume that
> example-alias-file was installed on department7.domain. Would it
> work or would I have to exclude the last line to prevent loops?


Well, you presumably only want to expand via the map if the address is
foo@domain rather than foo@???. But as I remember
Exim's workings, the loop will be caught and the map skipped the next
time it generates foo@???.

so, on mailhost.department7.domain:

## Main config
local_domains = domain:department7.domain

## Directors
# Expand mail addressed to the top-level domain
toplevel:
domains = domain
search_type = cdb
file = /etc/exim/toplevel.cdb
no_more # Immediately bounce any mail@domain NOT defined in the map
# Beyond this point, we can assume mail is addressed to department7.domain....
localusers:
# etc..

Some places would set up a rewrite configuration to change envelope
senders etc. from "department7.domain" to "domain", although I suspect
this is contentious.

> BTW, in a small test-installation everything works fine with a big
> alias-file. Did I overlook something? What would more experienced exim
> users suggest?


Like I say, LDAP or SQL are (IMHO) good ways of publishing the
information on a central server (kind of like NIS, but without being
NIS)- although if you make a dbm/cdb and rsync that out, then the
department servers don't depend on the central server. You compromise
between the two (or maybe run both systems).

HTH

SRH
-- 
+                  Steve Haslam                  |   W: +44-20-7447-1839   +
+  Just Another Production Engineer, Excite UK   |   M: +44-7775-645618    +
.   NP: Matthew Good Band - Enjoy The Silence (rare Depeche Mode cover)    .