Qmail is Public Domain
Developer Daniel Bernstein has placed his Qmail mail server in the public domain.
In an announcement on his website Bernstein has officially given version 1.0.3 of his software the legal status of Public Domain allowing the general public free use, distributing and code manipulation. The Qmail author warns anyone modifying the code to ensure compatibility by observing interfacing rules and using symbolic links to retain visibility of moved files.
Prior to the license change, Qmail was subject to copyright. The copyright owner Bernstein allowed use and distribution of the source code or binaries under certain conditions.
Qmail was created as an alternative to the classic Mail Transfer Agent (MTA) Sendmail. Daniel Bernstein designed and programmed the software with an eye to simplicity, robustness and security to the extent of offering a US$ 500 award for anyone who found a vulnerability.