Postfix is a Mail Transfer Agent for Unix and Unix- derivatives. The software should be compatible alternative to Sendmail time of development. The programmers stayed particular safety aspects. The source code of Postfix is under the IBM Public License, making it free software.
Postfix was developed in 1998 by Wietse Venema Zweitze and initially released under the name VMailer. As part of a trademark examination, it was discovered that the name of another brand is very similar and awarded the name " IBM Secure Mailer postfix ". Wietse Venema commented on the name search as follows:
The design goal was a fast, safe and easy system to administer.
Postfix is a fast and in relation to sendmail or qmail simple system to administer. Nevertheless: Like any MTA is postfix also tremendous knowledge of mail server logs and intensive knowledge of the system ahead because the configurations can be very complex depending on the application.
Particular emphasis was placed on Postfix on a simple administration (since there are only two configuration files essentially) and a secure mail server. It is call-compatible with Sendmail, so working with programs that would expect Sendmail instead of Postfix as a mail server. It is modular and performs its code as far as possible without root rights. Configuration changes to the running time possible and are taken without rebooting.
This modular structure is shown in the illustration below. In this, there are four types of elements:
All daemons (yellow ellipses) are started by the Postfix master process if necessary, and also monitored.