Postfix + Dovecot mailserver on Ubuntu

Tested on Ubuntu 12.10 VPS

We will create simple mailserver using postfix and dovecot. In current example we will use secure pop3 and smtp.

You should act as user so we are not adding this annoying "sudo" at the beginning of each command.

Install postfix

apt-get install postfix

NOTE: if you got the error: Package 'postfix' has no installation candidate. You should update the APT’s database:

apt-get update
apt-get upgrade

Usually postfix will show you the initial config "ui" . But you can check and reconfigure in case something wrong :

dpkg-reconfigure postfix

Check the next details and change in case it neccessary:

Mail server configuration type: “Internet Site”.
System mail name: mydomain.com
Root and postmaster mail recipient: leave blank
Other destinations to accept mail for: Add mydomain.com to the beginning of this comma-separated list.
Force synchronous updates?: No
Local networks: (All local subnets + Your Server IP Subnet)Usually you should add :  <YourIP>/32
Use procmail?: No
Mailbox size limit: “0″
Local address extension character: Leave as default.
Internet protocols to use: all

Create first user that will be used for mail. Let;s create user "test" with password "test1" . Change this password to more complex.

useradd test
passwd test

Create the place for user test mail.We will use Maildir format:

mkdir /home/test/Maildir 
postconf -e 'home_mailbox = Maildir/'
export MAIL=/home/test/Maildir
service postfix restart

Just to be sure that sendmail is stopped make the next:

service sendmail stop
service postfix restart

Lets test if transport system working properly:

telnet localhost 25
 Trying 127.0.0.1...
 Connected to localhost.localdomain.
 Escape character is '^]'.
 220 mail.vpsget.us ESMTP Postfix (Ubuntu) 

Send yourself a test message:

 ehlo localhost
 mail from: root@localhost
      250 2.1.0 Ok
 rcpt to: test@localhost
      250 2.1.5 Ok
 data
 Subject: testmail
 test 123
 .
      250 2.0.0 Ok: queued as 51A803C4B0AB
 quit
      221 2.0.0 Bye
      Connection closed by foreign host.
      You have mail in /home/test/Maildir

You can view this message with "mail" command. To use mail command install if not installed:

apt-get install heirloom-mailx
apt-get install mailutils

Run mail.you should see the subject line of your message. Press 1 and Enter to read it.

mail 
 Heirloom mailx version 12.5 6/20/10.  Type ? for help.
 "/home/test/Maildir": 1 message 1 new
 >N  1 root@localhost     Mon Jun 16 10:32   13/403   testmail
 ? 1

On this step postfix is working properly.

Now we need to install dovecot ,We will use mail storage with dovecot

apt-get install dovecot-imapd

You also could install all dovecot vrsions:

dovecot-pop3d                              
dovecot-common                           
dovecot-core//should be install as depency// 

Config /etc/dovecot/dovecot.conf

protocols = imap
mail_location =  maildir:~/Maildir

Sure you can change imap to pop3 if you like.

Check auth parameters in configfile etc/dovecot/conf.d/10-auth.conf

auth_mechanisms = plain login

Set maillocation in /etc/dovecot/conf.d/10-mail.conf

mail_location = maildir:~/Maildir

Add/uncomment the next config lines in appropriate section /etc/dovecot/conf.d/10-master.conf

unix_listener /var/spool/postfix/private/auth {
  mode = 0666
  user = postfix #sometimes can be disabled
 }