The following command use super user(root).

Remove Sendmail

zypper rm -n sendmail

Set DNS

follow this link DNS Server OpenSUSE

Install Postfix

zypper in postfix

Configure postfix

vim /etc/postfix/main.cf

# uncomment myhostname at line 102

myhostname = mail.malik.net.id

# uncomment mydomain at line 111
mydomain = malik.net.id

# uncomment myorigin at line 128
myorigin = $mydomain

# uncomment inet_interfaces = all at line 142
inet_interfaces = all

# uncomment inet_protokols = ipv4 at line 709
inet_protokols = all

# uncomment mydestinations at line 714
mydestinations = $myhostname, localhost.$mydomain, localhost, $mydomain

# uncomment mynetworks at line 290
mynetworks = 192.168.43.0/24, 127.0.0.0/8

# uncomment home_mailbox at line 446
home_mailbox = Maildir/

then save and exit

restart postfix

systemctl restart postfix

Add user

useradd --create-home suse
passwd ******

Install telnet

zypper in -y telnet

Test via telnet

telnet malik.net.id smtp

output

Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 localhost ESMTP

type

ehlo malik.net.id

result

250-localhost
250-PIPELINING
250-SIZE
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250-SMTPUTF8
250 CHUNKING

type

mailfrom:malik

result

250 2.1.0 Ok

type

rcpt to:suse

result

250 2.1.0 Ok

to input mail message

data

result

354 End data with <CR><LF>.<CR><LF>

then input mail message, like

hello
.

use dot (.) to complete message

result

250 2.0.0 Ok: queued as EF9CB16065A

to quit

quit

result

221 2.0.0 Bye
Connection closed by foreign host.
You have new mail in /home/malik/Maildir

Cek email

ls /home/malik/Maildir/new/

Install Dovecot

zypper in -y dovecot

Configure dovecot

vim /etc/dovecot/dovecot.conf

uncomment line 24

protocols = imap pop3 lmtp # submission

Edit file /etc/dovecot/conf.d/10-auth.conf file

vim /etc/dovecot/conf.d/10-auth.conf

set like this

disable_plaintext_auth = yes

Start dovecot

systemctl start dovecot

Testing dovecot

telnet malik.net.id pop3

result

Trying ::1...
Connected to localhost.
Escape character is '^]'.
+OK Dovecot ready.

user malik
+OK
pass *********
+OK Logged in.
retr 1
+OK 2388 octets

then quit

quit
+OK Logging out.
Connection closed by foreign host.

Install Squirrelmail

search squirrelmail using https://pkgs.org/ then follow installation instruction

configuration squirrelmail

cd /srv/www/htdocs/squirrelmail/config
./conf.pl

result

SquirrelMail Configuration : Read: config.php
Config version 1.4.0; SquirrelMail version 1.5.2 [SVN]
---------------------------------------------------------
Main Menu --
1.  Organization Preferences
2.  Server Settings
3.  Folder Defaults
4.  General Options
5.  User Interface
6.  Address Books
7.  Message of the Day (MOTD)
8.  Plugins
9.  Database
10. Language settings
11. Tweaks

D.  Set pre-defined settings for specific IMAP servers

C   Turn color on
S   Save data
Q   Quit

Command >> 

In this case i change organization name become Home then save

SquirrelMail Configuration : Read: config.php
Config version 1.4.0; SquirrelMail version 1.5.2 [SVN]
---------------------------------------------------------
Organization Preferences
1.  Organization Name      : Home
2.  Organization Logo      : ../images/sm_logo.png
3.  Org. Logo Width/Height : (0/0)
4.  Organization Title     : SquirrelMail $version
5.  Signout Page           : 
6.  Top Frame              : _top
7.  Provider link          : http://www.squirrelmail.org/
8.  Provider link text     : 

R   Return to Main Menu
C   Turn color on
S   Save data
Q   Quit

Command >> s

Data saved in config.php



Done activating plugins; registration data saved in plugin_hooks.php

Press enter to continue...

then return to main menu by hit R

Next is server setting like this

SquirrelMail Configuration : Read: config.php
Config version 1.4.0; SquirrelMail version 1.5.2 [SVN]
---------------------------------------------------------
Server Settings

General
-------
1.  Domain                 : localhost
2.  Invert Time            : false
3.  Sendmail or SMTP       : SMTP

A.  Update IMAP Settings   : localhost:143 (courier)
B.  Update SMTP Settings   : localhost:25

R   Return to Main Menu
C   Turn color on
S   Save data
Q   Quit

Command >> 

hit Q to quit

Create sqirrelmail vhost

follow this link

Then restart apache2

a2enmod rewrite
a2enmod mod_access_compat
systemctl restart apache2

Open browser

http://mail.malik.net.id

Source

https://www.unixmen.com/setup-local-mail-server-using-postfix-dovecot-squirrelmail-opensuse-13-x/