This is a complete standalone C implementation of the SRS (Sender
Rewriting Scheme) and includes a command line utility and daemon, test
utility and static and dynamic libraries. SRS is a stop-gap for users
of SPF (Sender Policy Framework).

libsrs_alt has been hugely successful and has been running on hundreds
of mail servers without fault. It has now been released with a couple
of minor updates and some code optimizations.