As a side note, the postscreen(8) man page [1] says that "this service was introduced with Postfix version 2.8.". Also RHEL 6 comes with postfix-2.6.6-2.2.el6_1

As a side note, the postscreen(8) man page [1] says that "this service was introduced with Postfix version 2.8.". Also RHEL 6 comes with postfix-2.6.6-2.2.el6_1.i686. [1] http://www.postfix.org/postscreen.8.html http://www.postfix.org/postscreen.8.html