The code examples for
auth.c are taken from pppd-1.2.1d and ppp-2.1.0e, Copyright (c) 1993 and The Australian National University and Copyright (c) 1989 Carnegie Mellon University.
Thanks to Marek Michalkiewicz <firstname.lastname@example.org> for writing and maintaining the Shadow Suite for Linux, and for his review and comments on this document.
Thanks to Ron Tidd <email@example.com> for his helpful review and testing.
Thanks to everyone who has sent me feedback to help improve this document.
Please, if you have any comments or suggestions then mail them to me.