Testing Postfix with sendmail

General Jun 18, 2019

Sendmail
Sendmail is a Mail Transfer Agent (MTA) using the Simple Mail Transfer Protocol (SMTP) to transfer mails.

Configuration File
For troubleshooting sendmail, the binary exist in the path below

[root@test /]# whereis sendmail
sendmail: /usr/sbin/sendmail /usr/sbin/sendmail.postfix /usr/lib/sendmail /usr/lib/sendmail.postfix /usr/share/man/man8/sendmail.8.gz

its main configuration file can be found in /etc/mail/sendmail.cf

Testing Sendmail
At times, you need to test your postfix configuration. This can be easily done with sendmail

[root@test /]# sendmail test@test.com
subject: Testing sendmail
This is a test mail. please ignore
not spam
.

A message should be received in your inbox coming from test@test.com

sendmail

pending mails
There are cases where your mails failed to be sent for whatever reasons that might exist. All mails in the queue can be flushed out to be sent once again, using the command below