Sender Rewriting Scheme (SRS) library and utility in C.
SRS is a scheme under development for email envelope sender
rewriting. In an SPF-compliant world, forwarded mail must be
rewritten to carry a local return path.
Read all about SRS at http://spf.pobox.com/srs.html

Author: James Couzens <jcouzens@6o4.ca>
WWW: http://www.libsrs.org/