Postfix 2 with Dovecot Installation HOWTO

1. Install Postfix

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yum install postfix
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2. Install Dovecot

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yum install dovecot
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3. Remove Sendmail

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yum remove sendmail
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4. Enable Postfix & Dovecot on start up

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chkconfig postfix on
chkconfig dovecot on
==================================


5. Configure Postfix

Postfix main configuration files are given below.

• /etc/postfix/main.cf
• /etc/postfix/master.cf

5.1 Configure main.cf

Open /etc/postfix/main.cf in an editor and make changes as explained below.

5.1.1 Set host name of the system.

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myhostname = mail.mailserver.com
=============================================

5.1.2 Set primary domain name of the server.

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mydomain = mailserver.com
==================================

5.1.3 Specify source domain of locally generated emails

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myorigin = $myhostname
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5.1.4 Specify postfix listening interfaces

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inet_interfaces = all
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5.1.5 Add list of locally hosted domains

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mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain, mail.$mydomain, www.$mydomain, ftp.$mydomain
=========================================================================================

5.1.6 Add relay permitted IP addresses

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mynetworks = 127.0.0.0/8
===================================================

5.1.7 Add relay permitted IP addresses

Specify "mynetworks_style = host" since Postfix should "trust" only the local machine.

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mynetworks_style = host
===================================================

5.1.8 Add relay permitted domains.

This should be kept as blank.

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relay_domains =
==========================

5.1.9 Configure Maildir as mailbox
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home_mailbox = Maildir/
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5.2 Configure Aliases

Create a user named "adminmails" to receive all administrator emails.

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useradd adminmails;
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Edit /etc/aliases

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# Person who should get root's mail
root:             adminmails
postmaster:       adminmails
abuse:            adminmails
mailer-daemon:    adminmails
=====================================================

Create adminmails' maildir

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su - adminmails
mkdir ~/Maildir
chmod -R 700 ~/Maildir
==============================================

5.3 Configure sendmail soft-links

=================================================================
ln -s /usr/sbin/sendmail.postfix /usr/sbin/sendmail
ln -s  /usr/lib/sendmail.postfix /usr/lib/sendmail
=================================================================


6. Adding a user

6.1 Creating the user

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useradd testusr
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6.2 Setting password for the user

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passwd testusr
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6.3 Creating Maildir

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su - testusr

mkdir ~/Maildir
chmod -R 700 ~/Maildir
========================================


7. Configure postfix as default mail server

7.1 Install system-switch-mail

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yum install system-switch-mail
============================================================

Now, run system-switch-mail command to configure postfix as default mail server


8. Start Postfix & Dovecot

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/etc/init.d/postfix start
/etc/init.d/dovecot start
============================================


9. Setting up virtual domains
9.1 Setup email domain in /etc/postfix/virtual file

To setup virtual domains, we need to add domains & email addresses in /etc/postfix/virtual file

Edit /etc/postfix/virtual and add following contents.

===================================================
cptest.org              this-text-is-ignored
postmaster@cptest.org   postmaster
test1@cptest.org        cptest-test1
test2@cptest.org        cptest-test2
@cptest.org             cptest-test1
====================================================

This will setup the email domain cptest.org and two email addresses test1@cptest.org & test2@cptest.org.

Here, cptest-test1 & cptest-test2 are UNIX users. cptest-test1 is also configured as the catchall address for all cptest.org email addresses.

9.2 Creating the user

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useradd cptest-test1
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9.3 Setting password for the user

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passwd cptest-test1
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9.4 Creating Maildir

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su - cptest-test1

mkdir ~/Maildir
chmod -R 700 ~/Maildir
========================================

9.5  Configure main.cf to use virtual domains

Edit /etc/postfix/main.cf and add following lines

======================================================================
virtual_alias_maps = hash:/etc/postfix/virtual
======================================================================

9.7 Create postfix virtual domains database

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postmap /etc/postfix/virtual
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9.8 Reload postfix

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/etc/init.d/postfix reload
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