Contents
Description
Postfix is a free and open-source mail transfer agent (MTA) that routes and delivers electronic mail.
It is released under the IBM Public License 1.0 which is a free software license. Alternatively, starting with version 3.2.5, it is available under the Eclipse Public License 2.0 at the user's option.
Originally written in 1997 by Wietse Venema at the IBM Thomas J. Watson Research Center in New York, and first released in December 1998[3], Postfix continues as of 2020 to be actively developed by its creator and other contributors. The software is also known by its former names VMailer and IBM Secure Mailer.
In August 2019 a study performed by E-Soft, Inc., approximately 34% of the publicly reachable mail-servers on the Internet ran Postfix, making it the second most popular mail server behind Exim.
(source: WikiPedia)
Operation
Working with queues
To view the mailqueue
postqueue -p
To show a mail in the queue
postcat -vq MSGID
To flush the queue
postqueue -f
to delete the queued messages
postsuper -d ALL