Virtual Users And Domains With Postfix, Courier And MySQL (Debian Etch)

Version 1.0
Author: Falko Timme
Last edited 05/25/2007

This tutorial is Copyright (c) 2007 by Falko Timme. It is derived from a tutorial from Christoph Haas which you can find at http://workaround.org. You are free to use this tutorial under the Creative Commons license 2.5 or any later version.

This document describes how to install a mail server based on Postfix that is based on virtual users and domains, i.e. users and domains that are in a MySQL database. I'll also demonstrate the installation and configuration of Courier (Courier-POP3, Courier-IMAP), so that Courier can authenticate against the same MySQL database Postfix uses.

The resulting Postfix server is capable of SMTP-AUTH and TLS and quota (quota is not built into Postfix by default, I'll show how to patch your Postfix appropriately). Passwords are stored in encrypted form in the database (most documents I found were dealing with plain text passwords which is a security risk). In addition to that, this tutorial covers the installation of Amavisd, SpamAssassin and ClamAV so that emails will be scanned for spam and viruses.

The advantage of such a "virtual" setup (virtual users and domains in a MySQL database) is that it is far more performant than a setup that is based on "real" system users. With this virtual setup your mail server can handle thousands of domains and users. Besides, it is easier to administrate because you only have to deal with the MySQL database when you add new users/domains or edit existing ones. No more postmap commands to create db files, no more reloading of Postfix, etc. For the administration of the MySQL database you can use web based tools like phpMyAdmin which will also be installed in this howto. The third advantage is that users have an email address as user name (instead of a user name + an email address) which is easier to understand and keep in mind.

This howto is meant as a practical guide; it does not cover the theoretical backgrounds. They are treated in a lot of other documents in the web.

This document comes without warranty of any kind! I want to say that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!

 

1 Preliminary Note

This tutorial is based on Debian Etch, so you should set up a basic Debian Etch installation before you continue with this tutorial. The system should have a static IP address. I use 192.168.0.100 as my IP address in this tutorial and server1.example.com as the hostname.

 

2 Install Postfix, Courier, Saslauthd, MySQL, phpMyAdmin

To install Postfix, Courier, Saslauthd, MySQL, and phpMyAdmin, we simply run

apt-get install postfix postfix-mysql postfix-doc mysql-client mysql-server courier-authdaemon courier-authlib-mysql courier-pop courier-pop-ssl courier-imap courier-imap-ssl postfix-tls libsasl2 libsasl2-modules libsasl2-modules-sql sasl2-bin libpam-mysql openssl phpmyadmin apache2 libapache2-mod-php5 php5 php5-mysql

You will be asked a few questions:

Create directories for web-based administration ? <-- No
General type of configuration? <-- Internet Site
Mail name? <-- server1.example.com
SSL certificate required <-- Ok

 

3 Apply The Quota Patch To Postfix

We have to get the Postfix sources, patch it with the quota patch, build new Postfix .deb packages and install those .deb packages:

apt-get install build-essential dpkg-dev fakeroot debhelper libgdbm-dev libldap2-dev libpcre3-dev libssl-dev libsasl2-dev postgresql-dev po-debconf dpatch libdb4.3-dev libmysqlclient15-dev lsb-release libcdb-dev

cd /usr/src
apt-get source postfix

(Make sure you use the correct Postfix version in the following commands. I have Postfix 2.3.8 installed. You can find out your Postfix version by running

postconf -d | grep mail_version

The output should look like this:

server1:~# postconf -d | grep mail_version
mail_version = 2.3.8
milter_macro_v = $mail_name $mail_version

)

wget http://vda.sourceforge.net/VDA/postfix-2.3.8-vda.patch.gz
gunzip postfix-2.3.8-vda.patch.gz
cd postfix-2.3.8
patch -p1 < ../postfix-2.3.8-vda.patch
dpkg-buildpackage

You might see a warning like this at the end of the dpkg-buildpackage command:

(WARNING: Failed to sign .dsc and .changes file)

You can ignore this message.

To install our new Postfix package, we run

cd ..
dpkg -i postfix_2.3.8-2_i386.deb
dpkg -i postfix-mysql_2.3.8-2_i386.deb

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From: at: 2007-06-06 20:11:22

 Hi,

 I don't understand, why you use the smtp-PAM-Module?!

 By the way: In Debian Etch you have to activate DCC in /etc/spamassassin/v310.pre

 Regards,

Hypz 

From: at: 2008-01-29 12:11:27

VERY nice howto. It worked like a dream.
And setting up Squirrelmail for this was a breeze too. 

I encountered some problems while I followed the guide though, which I have listed in my blog @ Ronin's blog[^].

 One was a bug I encountered within Courier-Saslauthdaemon, and 2 were some banal problems with Squirrelmail. But I managed to solve them with some googling around ^^

From: Juan Carlos at: 2008-12-16 17:56:05

hello as are wanting to loguiarme in mailboxes me introduce the following error:
 
Dec 16 12:43:19 linuxdeb authdaemond: stopping authdaemond children
Dec 16 12:43:19 linuxdeb authdaemond: modules="authmyslq", daemons=5
Dec 16 12:43:19 linuxdeb authdaemond: Installing libauthmyslq
Dec 16 12:43:19 linuxdeb authdaemond: libauthmyslq.so: cannot open shared object file: No such file or directory
Dec 16 12:43:46 linuxdeb courierpop3login: Connection, ip=[::ffff:127.0.0.1]
Dec 16 12:43:54 linuxdeb courierpop3login: LOGIN FAILED, user=juan, ip=[::ffff:127.0.0.1]
Dec 16 12:44:03 linuxdeb courierpop3login: LOGOUT, ip=[::ffff:127.0.0.1]
Dec 16 12:44:03 linuxdeb courierpop3login: Disconnected, ip=[::ffff:127.0.0.1]
~
 
that can be
 

From: at: 2007-06-24 18:58:29

This setup seems to be extremely insecure.

Mysql function encrypt () encrypts (on some systems, e.g. my Debian Etch) only first eight characters of a string, making hacking of a mailbox extremely easy. For example, passwords

12345678LHKuhlhKJgkZgHklu

and

12345678

both allow the user to log in (think about people who use password5468d - AOL had similar problem recently).

From: at: 2007-06-24 19:10:25

To fix the security problem I mentioned above, you may possibly use other cyphers, I found this text:

 

User question/comment: I thought MYSQL_CRYPT_PWFIELD only handles the ENCRYPT() function in stead of MD5() (see postfix-mysql setup). Correct me when I'm wrong

User question/comment: MYSQL_CRYPT_PWFIELD only specifies the name of database field,
it has nothing to do with crypt format. authlib
can automatically detect several different formats of password hash, please refer to cryptpassword.c
inside courier authlib source code for more info. Basically it checks if the first
few characters of password hash is:

  • "$1$": password is MD5 format password used by all Linux systems.
  • "{MD5}": this is followed by standard MD5 hash of password phrase.
  • "{SHA}": this is followed by standard SHA hash of password phrase.
  • "{SHA256}": this is followed by standard SHA256 hash of password phrase.
  • "{CRYPT}": this is followed by standard DES crypt() hash of password phrase.

Source:

http://postfix.wiki.xs4all.nl/index.php?title=Virtual_Users_and_Domains_with_Courier-IMAP_and_MySQL 

From: at: 2008-07-25 19:30:16

Hi

To fix this problem, just use md5-crypt passwords (as used in /etc/shadow files, starting with $1$) for your mailboxes.

This should work. If it doesn't, append "md5=true" on both lines in /etc/pam.d/smtp.

From: at: 2008-01-18 16:27:33

apt-get source postfix did not work for me.

Replaced by 'apt-src install postfix'.

 

From: Anonymous at: 2009-06-17 20:42:27

Hi,

 under debian edge there is a bug in clamav so that it produces 100% cpu load and can´t open a unix socket.

Like this: 

connect to UNIX socket /var/run/clamav/clamd.ctl: No such file or directory

You have to update the clamav to solve this problem. Add folowing package sources in sources.list

deb http://volatile.debian.org/debian-volatile etch/volatile main

 then do: apt-get update

and install the packages: 

clamav-daemon
clamav-freshclam
clamav-base
clamav

then it sould work.

Good Luck

 Kruser

From: at: 2008-01-26 16:54:35

Hi,

Great Howto, thank you very much for your work.

Just a comment: you don't need to set sql parameters and mysql as auxprop_plugin in /etc/postfix/sasl/smtpd.conf as you intend to use PAM for authentication.

The following /etc/postfix/sasl/smtpd.conf should suffice:

pwcheck_method: saslauthd
mech_list: plain login
allow_plaintext: true

This way, plain PAM will be used, with the options you set in /etc/pam.d/smtpd. Indeed, you don't even need to install libsasl2-modules-sql package (but you still do need libpam-mysql, of course).

Best regards,

Alberto Caso
Adaptia

From: at: 2007-06-05 19:31:53

Hi,

 why do you add this SMTP-PAM-Module? I don't see any sense in this.

By the way: In Debian Etch you have to enable DCC in /etc/spamassassin/v310.pre

Regards,

Hypz 

From: at: 2007-07-11 21:17:01

Hi, first ov all thanks for the tut.

In etch you also have to activate spamassasin in /etc/default/spamassasin "ENABLE = 1"

Also I found this in the Fedora tut. about the paths ( it worked for me on etch ):

the dcc_path to the socket is (as I followed exacly the way of installing as described in this tut):

/var/lib/dcc/dccifd

* dcc_add_header and  pyzor_add_header are deprecated (Cf. http://spamassassin.apache.org/full/2.6x/dist/doc/Mail_SpamAssassin_Conf.txt), instead use respectively add_header all DCC _DCCB_: _DCCR_ and add_header all Pyzor _PYZOR_

 * to make amavis keep a part of the spamassassin header, add the following lines to your amavisd.conf :

$remove_existing_spam_headers = 0;

$sa_spam_report_header = 1;

Please correct me if I'm wrong. But it looks like this how it worked for me.

Greets Josh 

 

From: at: 2007-07-20 18:32:01

You are wrong, spamd is typically not used along with amavisd-new. amavisd-new calls spamassassin directly via Perl module Mail::SpamAssassin. So, I suggest leaving the default of "ENABLE = 0" in /etc/default/spamassasin.

From: Tim at: 2009-06-14 22:17:31

I was able to make this run in lenny with some light modifications, no DCC (debian boycotted it in lenny), etc.

Everything works nicely, but spamassassin, razor and pyzor do not print any headers in the e-mail, when "$sa_tag_level_deflt = undef;".

On the amavis startup logging, it does show razor2 being loaded, but not pyzor, while both are installed (did not configuration though).

Amavis is logging to mail.log whether the message is spam or not, and the X-Virus-Scanned shows, but no spamassassin, razor (and pyzor, but it won't even load) headers. Should I just install the perl package for spamassassin? I currently have the "spamassasin" lenny deb installed.

 

"$QUARANTINEDIR = "$MYHOME/virusmails";
$quarantine_subdir_levels = 1; # enable quarantine dir hashing

$log_recip_templ = undef;    # disable by-recipient level-0 log entries
$DO_SYSLOG = 1;              # log via syslogd (preferred)
$syslog_ident = 'amavis';    # syslog ident tag, prepended to all messages
$syslog_facility = 'mail';
$syslog_priority = 'debug';  # switch to info to drop debug output, etc

$enable_db = 1;              # enable use of BerkeleyDB/libdb (SNMP and nanny)
$enable_global_cache = 1;    # enable use of libdb-based cache if $enable_db=1

$inet_socket_port = 10024;   # default listening socket

$sa_spam_subject_tag = '***SPAM*** ';
$sa_tag_level_deflt = undef;   # add spam info headers if at, or above that level
$sa_tag2_level_deflt = 4.00;   # add 'spam detected' headers at that level
$sa_kill_level_deflt = 6.31;   # triggers spam evasive actions
$sa_dsn_cutoff_level = 10;     # spam level beyond which a DSN is not sent
"

Thanks!

Tim

From: at: 2008-02-17 22:56:39

I got this error in /var/log/mail.log
Can't connect to UNIX socket /var/run/clamav/clamd.ctl: No such file or directory

Sollution -> http://blog.brachium-system.net/categories/7-virus

From: at: 2010-08-21 19:37:35

Hi i folowed this guide and the server has worked well for over a year but now clamd uses up 100% of my cpu.

 

From: at: 2007-06-10 11:51:45

Thanks for this tutorial!

Whats with automatic custom rulesets updates for SpamAssassin?

=> http://www.howtoforge.com/virtual_postfix_mysql_quota_courier_p4

 Nico

From: at: 2008-05-27 15:32:58

You need to use clamav from Debian's volatile repository, otherwise this won't work at all.

On more thing, if you create new email account, and than try to fetch mail for it and fail miserably, than send an email to it, and then try again.

Good tutorial. Thanks ;) 

From: Bruno Taranto Alvim at: 2008-09-30 23:30:19

Change 2 files (mysql-virtual_mailboxes.cf and authmysqlrc) to Maildir work.

mail:/etc/postfix# more mysql-virtual_mailboxes.cf

user = postfix password = postfix dbname = postfix query = SELECT CONCAT(SUBSTRING_INDEX(email,'@',-1),'/','',SUBSTRING_INDEX(email,'@',1),'/','Maildir/') FROM users WHERE email='%s' hosts = 127.0.0.1

mail:/etc/courier# more authmysqlrc

MYSQL_SERVER localhost MYSQL_USERNAME postfix MYSQL_PASSWORD postfix MYSQL_PORT 0 MYSQL_DATABASE postfix MYSQL_USER_TABLE users MYSQL_CRYPT_PWFIELD password #MYSQL_CLEAR_PWFIELD password MYSQL_UID_FIELD 5000 MYSQL_GID_FIELD 5000 MYSQL_LOGIN_FIELD email MYSQL_HOME_FIELD "/home/vmail" MYSQL_MAILDIR_FIELD CONCAT(SUBSTRING_INDEX(email,'@',-1),'/','',SUBSTRING_INDEX(email,'@',1),'/','Maildir/') #MYSQL_NAME_FIELD MYSQL_QUOTA_FIELD quota

Now you can receive and get!