test postfix mail server

1. Establish a TCP connection to port 25 which is postfix port :

[root@mail ~]# telnet localhost 25

You should receive a 220 response:

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 mail.zimbra.local ESMTP Postfix

Postfix is listening and we can communicate with SMTP now.

2. Next,greet the postfix server. The function is considered same with postman or transport :

Helo mail.zimbra.local

The postfix mail server should respond as below :

250 mail.zimbra.local

3. Inform the postfix server know who the sender is:

MAIL FROM:<admin@zimbra.local>

You will get ‘250’ output if the postfix accepts the sender address :

250 2.1.0 Ok

4. Specify the recipient of the email :

RCPT TO:<user@zimbra.local>

If Postfix accepts the recipient address will returned 250 response :

250 2.1.5 Ok

5. Send the actual Email with subject and body of the email :

DATA

Postfix agrees and feedback us to start actual email and returned this output :

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

6. Start compose the mail, type the word ‘Subject:’ for email subject then enter. Type email body end our input with a dot.

Subject: My Test Email
This is the body of the Email
.

As before, if postfix agress and accepts the email, it will returned 250 response :

250 2.0.0 Ok: queued as 194869C1AB

7. Postfix test fixt telnet finished at the moment, So you can quit :

quit

221 2.0.0 Bye
Connection closed by foreign host.

managed server