I have postfix email server on Ubuntu 11.04 version. I upgraded installed packages using the following command

sudo aptitude update && sudo aptitude safe-upgrade

Once I update those packages, I couldn't connect my email from my client machine. So I tested my postfix server using telnet.

telnet mail.mydomain.com 25

I got the following result for the above command.

Connected to mail.mydomain.com.
Escape character is '^]'.

I am very new to this postfix server. I couldn't understand whether my postfix server corrupted or not? Why I couldn't connect my email after updating the packages?

1 Answer 1


Google "check email server using telnet" no quotes

Some of your output may vary but if you do not get any errors and you receive the email from the email server you can know that emial is flowing properly.

Also im not 100% sure if this answers your qestion however this is the way the check your email server form command line.

Also when using telnet be careful as 1 typo means you have start all over again.

From the port25 website

Here are all the commands I have bolded the command you will need to type out vs the output you will see.

telnet mail.port25.com 25


Connected to mail.port25.com (

Escape character is '^]'.

220 mail.port25.com (PowerMTA(TM) v4.0) ESMTP service ready

EHLO server.example.com

250-mail.port25.com says hello








250-SIZE 54525952


250 DSN

MAIL FROM: <[email protected]>

250 2.1.0 MAIL ok

RCPT TO: <[email protected]>

250 2.1.5 <[email protected]> ok


354 send message

From: "John Smith" <[email protected]>

To: "Jane Doe" <[email protected]>

Subject: test message sent from manual telnet session

Hello World,


250 2.6.0 message received


221 2.0.0 mail.port25.com says goodbye

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