Here is quick guide on how I configured Exim 4 to let a Debian Squeeze server send mails through a GMail account. This article is just a rip-off of a tutorial I found on the web , which is itself an updated version of a Debian’s Wiki page  .

Debian come with Exim (v4.72) pre-installed: it’s the default MTA on this distribution. There is absolutely no need to install extra packages. Let’s start right away by calling Exim’s configuration wizard: 

1$ dpkg-reconfigure exim4-config

Here are the options I choose in each step of the wizard:

  1. Choose Mail sent by smarthost; received via SMTP or fetchmail .

  2. System mail name: server.deldycke.com .

  3. IP addresses to listen on for incoming SMTP connections: 127.0.0.1 ; ::1 (which is the default proposed value).

  4. Other destinations for which mail is accepted: leave blank.

  5. Machines to relay mail for: leave blank.

  6. Machine handling outgoing mail for this host (smarthost): smtp.gmail.com::587 .

  7. Hide local mail name in outgoing mail: No .

  8. Keep number of DNS-queries minimal (Dial-on-Demand): No .

  9. Mailboxes format: mbox .

  10. Split configuration into small files: No .

All these parameters you just answered are saved in the /etc/exim4/update-exim4.conf.conf : 

# /etc/exim4/update-exim4.conf.conf
#
# Edit this file and /etc/mailname by hand and execute update-exim4.conf
# yourself or use 'dpkg-reconfigure exim4-config'
#
# Please note that this is _not_ a dpkg-conffile and that automatic changes
# to this file might happen. The code handling this will honor your local
# changes, so this is usually fine, but will break local schemes that mess
# around with multiple versions of the file.
#
# update-exim4.conf uses this file to determine variable values to generate
# exim configuration macros for the configuration file.
#
# Most settings found in here do have corresponding questions in the
# Debconf configuration, but not all of them.
#
# This is a Debian specific file

dc_eximconfig_configtype='smarthost'
dc_other_hostnames=''
dc_local_interfaces='127.0.0.1 ; ::1'
dc_readhost=''
dc_relay_domains=''
dc_minimaldns='false'
dc_relay_nets=''
dc_smarthost='smtp.gmail.com:587'
CFILEMODE='644'
dc_use_split_config='false'
dc_hide_mailname='false'
dc_mailname_in_oh='true'
dc_localdelivery='mail_spool'

Then I updated the /etc/exim4/exim4.conf.template to add proper handling of GMail SMTP server. Here are the differences between the untouched original exim4.conf.template file and my version: 

--- /etc/exim4/exim4.conf.template-orig  2011-05-03 10:49:43.207938577 +0200
+++ /etc/exim4/exim4.conf.template       2011-05-03 10:52:26.235438776 +0200
@@ -1077,15 +1077,11 @@
 # domains, you'll need to copy the dnslookup_relay_to_domains router
 # here so that mail to relay_domains is handled separately.

-smarthost:
-  debug_print = "R: smarthost for $local_part@$domain"
-  driver = manualroute
-  domains = ! +local_domains
-  transport = remote_smtp_smarthost
-  route_list = * DCsmarthost byname
-  host_find_failed = defer
-  same_domain_copy_routing = yes
-  no_more
+send_via_gmail:
+       driver = manualroute
+       domains = ! +local_domains
+       transport = gmail_smtp
+       route_list = * smtp.gmail.com

 .endif

@@ -1632,6 +1628,12 @@
 # to a smarthost. The local host tries to authenticate.
 # This transport is used for smarthost and satellite configurations.

+gmail_smtp:
+       driver = smtp
+       port = 587
+       hosts_require_auth = $host_address
+       hosts_require_tls = $host_address
+
 remote_smtp_smarthost:
   debug_print = "T: remote_smtp_smarthost for $local_part@$domain"
   driver = smtp
@@ -1759,6 +1761,11 @@

 begin authenticators

+gmail_login:
+       driver = plaintext
+       public_name = LOGIN
+       client_send = : [email protected] : XXXXXXXXX
+

 #####################################################
 ### end auth/00_exim4-config_header
@@ -1999,27 +2006,27 @@
                    ^${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
 .endif

-login:
-  driver = plaintext
-  public_name = LOGIN
-.ifndef AUTH_CLIENT_ALLOW_NOTLS_PASSWORDS
-  # Return empty string if not non-TLS AND looking up $host in passwd-file
-  # yields a non-empty string; fail otherwise.
-  client_send = "<; ${if and{\
-                          {!eq{$tls_cipher}{}}\
-                          {!eq{PASSWDLINE}{}}\
-                         }\
-                      {}fail}\
-                 ; ${extract{1}{::}{PASSWDLINE}}\
-                ; ${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
-.else
-  # Return empty string if looking up $host in passwd-file yields a
-  # non-empty string; fail otherwise.
-  client_send = "<; ${if !eq{PASSWDLINE}{}\
-                      {}fail}\
-                 ; ${extract{1}{::}{PASSWDLINE}}\
-                ; ${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
-.endif
+#login:
+#  driver = plaintext
+#  public_name = LOGIN
+#.ifndef AUTH_CLIENT_ALLOW_NOTLS_PASSWORDS
+#  # Return empty string if not non-TLS AND looking up $host in passwd-file
+#  # yields a non-empty string; fail otherwise.
+#  client_send = "<; ${if and{\
+#                          {!eq{$tls_cipher}{}}\
+#                          {!eq{PASSWDLINE}{}}\
+#                         }\
+#                      {}fail}\
+#                 ; ${extract{1}{::}{PASSWDLINE}}\
+#               ; ${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
+#.else
+#  # Return empty string if looking up $host in passwd-file yields a
+#  # non-empty string; fail otherwise.
+#  client_send = "<; ${if !eq{PASSWDLINE}{}\
+#                      {}fail}\
+#                 ; ${extract{1}{::}{PASSWDLINE}}\
+#               ; ${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
+#.endif
 #####################################################
 ### end auth/30_exim4-config_examples
 #####################################################

Now all we have to do is to regenerate Exim’s configuration and restart the mail server: 

1$ update-exim4.conf
2$ /etc/init.d/exim4 restart

You can then send a dummy email to test your mail system: 

1$ mail [email protected]
2Subject: This is an exim test
3.
4Cc:
5Null message body; hope that's ok

And check in the log that everything’s fine: 

1$ tail -F /var/log/exim4/mainlog
22011-05-03 10:56:32 1QHBPE-0000ne-CW <= [email protected] U=root P=local S=362
32011-05-03 10:56:36 1QHBPE-0000ne-CW => [email protected] R=send_via_gmail T=gmail_smtp H=gmail-smtp-msa.l.google.com [209.85.227.109] X=TLS1.0:RSA_ARCFOUR_SHA1:16 DN="C=US,ST=California,L=Mountain View,O=Google Inc,CN=smtp.gmail.com"
42011-05-03 10:56:36 1QHBPE-0000ne-CW Completed

9 archived comments

Comments are closed. These were posted on Disqus, and are archived here.

  1. Kevin Deldycke Author

    And if you want to forward all system messages sent to the root user on your machine, don't forget to edit the /etc/aliases file. In mine I just edited the root entry to something like that:

    root: [email protected]
    1. Kevin Deldycke Author

      And if the latter is not enough, you may consider adding a .forward file in the /root/ directory, or even update the /etc/email-addresses file.

  2. Xeyo

    ... it's works!
    Thank You :-)

  3. o_be_one

    Very very very good howto.
    Big thanks, it works great !

    But my server's name is same as my mail so my server consider that its a local mail and doesn't send mails to my domain with GMail ... They stay in local mailboxes :/.

    Note : my domain is registered on "Google Apps".

  4. Frank

    "Here are the differences between the untouched original exim4.conf.template file and my version"

    How can is see what the difference is? Because my original file is much larger. You changed a seperate part of it or something?

    Pleas help - Getting stuck on this for 4 days now :@ :@ :@

    1. Frank

      Note that I'm using Debian 6 Squeeze on my VPS with Google Apps Free.

    2. Kevin Deldycke Author

      How can is see what the difference is?

      It's not the whole file. It's a unified diff.

  5. Dave

    Sorry I'm so dumb, but I'm struggling to get this to work. I have an email account on gmail. I can name my system anything I want. But I don't see where I put my gmail user name and password in the template file. The error message I get back from gmail is gmail_login authenticator failed UserName and Password not accepted. Can anyone help explain it to me? I'd really like to get this to work.

  6. Simon

    Zillion thanks to you !