This milter implemets SRS (Sender Rewriting Scheme) that can be used to
fix envelope MAIL FROM for forwarded mails protected by SPF. It can be
configured in two modes for:

* Incoming mail -- rewrite RCPT TO addresses in SRS format back
* Outgoing mail -- rewrite MAIL FROM address to SRS format

Homepage:
https://github.com/emsearcy/srs-milter
