The original documentation for Mail::SRS version 0.10 is no longer
relevant to newer versions of this module, but it is preserved here
for posterity just in case of questions. See also README.pobox,
which was a part of the original distribution.

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The Sender Rewriting Scheme preserves .forward functionality
in an SPF-compliant world.

This module should be considered alpha at this
time. Documentation is incomplete. Pobox.com decided to
publish Mail::SRS to CPAN anyway because there seems to be
a fair amount of interest out there in implementing SRS.

SPF requires the SMTP client IP to match the envelope sender
(return-path).  When a message is forwarded through an
intermediate server, that intermediate server may need to
rewrite the return-path to remain SPF compliant.  If the
message bounces, that intermediate server needs to validate
the bounce and forward the bounce to the original sender.

SRS provides a convention for return-path rewriting which
allows multiple forwarding servers to compact the return-path.
SRS also provides an authentication mechanism to ensure that
purported bounces are not arbitrarily forwarded.

SRS is documented at http://spf.pobox.com/srs.html

A given SRS address is valid for one month by default.

Cookies are relatively unique.

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