NAME

       Mail::Milter::Wrapper::DecodeSRS - milter wrapper to decode SRS-encoded return path

SYNOPSIS

           use Mail::Milter::Wrapper::DecodeSRS;

           my $milter = ...;
           my $wrapper = new Mail::Milter::Wrapper::DecodeSRS($milter);

           my $wrapper2 = &DecodeSRS($milter); # convenience

DESCRIPTION

       Mail::Milter::Wrapper::DecodeSRS is a convenience milter wrapper which decodes MAIL FROM:
       return paths which have been encoded by the Sender Rewrite Scheme, SRS.  (More
       information:  http://www.libsrs2.org/) This wrapper internally understands both the SRS0
       and SRS1 encoding schemes documented by the Mail::SRS author.

       The decoded address is made available to the contained milter via the "envfrom" callback,
       in the same way that a raw address would.

       NOTE:  If the address is not SRS encoded, the contained milter is NOT called for the
       duration of the message; instead, SMFIS_ACCEPT is returned.  This is because the milter
       writer is expected to use this wrapper in a chain that also includes the contained milter
       without wrapping, in order to prevent a malicious sender from using SRS to bypass access
       checks.

       For instance, the following is a proper usage of this wrapper in a chain:

           my $envfrommilter = ...;

           my $combinedmilter = new Mail::Milter::Chain(
               new Mail::Milter::Wrapper::UnwrapSRS($envfrommilter),
               $envfrommilter
           );

       This behavior can also be used if, e.g., the MTA already does one form of MAIL FROM:
       check, and the contained milter repeats that same database check against SRS rewritten
       addresses.  (A good example would be a milter emulating Sendmail's access_db map.)

AUTHOR

       Todd Vierling, <tv@duh.org> <tv@pobox.com>

SEE ALSO

       Mail::Milter::Wrapper