Ensure that sendmail is stopped in the host
- systemctl stop sendmail
- systemctl disable sendmail
Install the postfix package
- yum install postfix
Backup the main postfix configuration file in case it is required for future use
- cp /etc/postfix/main.cf /etc/postfix/main.cf.orig
Edit the configuration file
- vi /etc/postfix/main.cf
Ensure that the following are enabled, and other similar entry is commented
========
- myhostname = <your FQDN>
- mydomain = <your FQDN>
- myorigin = $myhostname
- inet_interfaces = all
- mynetworks = <your IP/subnet>, 127.0.0.0/8
- home_mailbox = Maildir/
=======
Restart postfix
- systemctl restart postfix
Verify if SMTP is working
- netstat -na | grep 25
If it is working make sure sendmail, or any other SMTP service is not installed
Start the postfix service
- systemctl start postfix
- systemctl enable postfix
Verify if the SMTP service is running
- netstat -na | grep 25
Note: The server will send mail only to users in its domain !!
====== ===== ====== ===== ====== =====
Let us test if the server is working fine.
Create a new user called “anyuser”
- useradd anyuser
Do a telnet session to SMTP server
- [root@host ~]# telnet localhost 25
- Trying ::1…
- Connected to localhost.
- Escape character is ‘^]’.
- 220 <my FQDN> ESMTP Postfix
- ehlo <my FQDN>
- 250-<my FQDN>
- 250-PIPELINING
- 250-SIZE 10240000
- 250-VRFY
- 250-ETRN
- 250-ENHANCEDSTATUSCODES
- 250-8BITMIME
- 250 DSN
- MAIL FROM: root@<my FQDN>
- 250 2.1.0 Ok
- RCPT TO: <anyuser@my FQDN>
- 250 2.1.5 Ok
- DATA
- 354 End data with <CR><LF>.<CR><LF>
- Hello anyuser
- .
- quit
Go to the home folder of the anyuser and check if the Maildir folder is automatically created, and the file file is there.