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I currently have two servers

  • first.mydomain.com (ip:A.B.C.28) and
  • second.mydomain.com (ip:A.B.C.30)

Both servers have DNS and reverse dns entries, e.g. A.B.C.30 -> second.mydomain.com

The first.mydomain.com - handles all emails from/to the mydomain.com (e.g. the MX for mydomain.com pointing to first.mydomain.com)

The second is configured (exim/dovecot) for handling emails for two other domains. (virt1.com and virt2.com). MX records are OK, virt1.com mail is handled by 100 second.mydomain.com

All basic things works (TLS, dovecot-auth.. etc..) Receiving email is OK to - delivering into /home/mail/virt1.com/user/Maildir. Outgoing mail is delivering too (but strange), so routers, and transports works, but:

For example, when: the user@virt1.com sending email to someuser@example.com via second.mydomain.com, got strange things in the headers.

Return-Path: <"user@virt1.com"@mydomain.com>
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ??? - added mydomain
Received: ... deleted ...
Received: ... deleted ...
Received: from somedsl.someisp.com ([X.X.X.X]:21563 helo=marvin.local)
    by second.mydomain.com with esmtpsa (TLSv1:DHE-RSA-CAMELLIA256-SHA:256)
    (Exim 4.80.1 (FreeBSD))
    (envelope-from <"user@virt1.com"@second.mydomain.com>)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ??? added FQDN
    id 1UVf91-000ALf-fb
    for someuser@example.com; Fri, 26 Apr 2013 11:40:43 +0200
Date: Fri, 26 Apr 2013 11:40:42 +0200
From: username <user@virt1.com>
Reply-To: user@virt1.com
To: someuser@example.com
Subject: test message
Sender: "user@virt1.com"@second.mydomain.com
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ??? added the FQDN again

start of my exim config is:

local_interfaces = A.B.C.30
primary_hostname = second.mydomain.com
domainlist local_domains = dsearch;/etc/mail/virtual #each domain has its own subdir

Yet, haven't any rewriting rules.

Questions:

  • should i set the smtp_active_hostname to something, instead of second.mydomain.com?
  • need setup some heeader rewiting rules? (probably yes)
  • what else i should check?
  • some idea how to rid off the above weird headers?

The above is running in one freebsd jail, but it probably doesn't matter...

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1 Answer 1

up vote 2 down vote accepted

The first mail servers (of which Exim is derived from a very early one) were designed at a time when it was common for an email address for userX@example.com to belong to a real unix user named "userX". As such, when it constructs the Sender header and other headers, it would use the username @ default_domainname. The username part is referred to in Exim as the local_part.

In modern systems, it is much more common to have virtual users, where an exim server can receive email to a domain that is not the default domain, and the local_part is likely not a valid local user, or there may be multiple email addresses all with the same local_part. In systems like this, instead of authenticating as "userX", it's more common to authenticate as "userX@example.com". Exim internally will treat that whole string as the username unless you configure it otherwise.

http://www.exim.org/exim-html-current/doc/html/spec_html/ch-message_processing.html#SECTsubmodnon

The control = submission line tells exim to apply certain fixups to the message that gets submitted, including creating those headers you mentioned. Change it to:

control = submission/sender_retain

to indicate that you want Exim to treat the submitted name as the full userX@example.com instead of just the local_part, meaning exim won't try to append the default domain name to what was submitted. The exim documentation linked above has a lot of great detail on this whole message submission and fixup process.

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unfortunately i can upvote only once! THANK YOU VERY MUCH! :) :) –  jm666 Apr 26 '13 at 16:27

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