[Pymilter] Possible to use a milter for reverse SRS?

[Stuart D. Gathman]

On Mon, 28 Jan 2019, Melanie Dymond Harper wrote:

>>  # do not rewrite mail to these domains
>>  ;nosrs = braindeadmail.com


>
> It is more clear but, unfortunately, no more functional on this end.
> fwdomain and srs are now both set to the same value (and they are
> being picked up correctly; I temporarily added a couple of print
> statements to check), reject_spoofed is set to true and has been all
> along. socketname and miltername are set to correspond to the values
> being used in sendmail.mc. miltersrs is set to true. Hm. - Mel

Are you sure you are testing actual DSNs?  Only DSNs should be 
SRS decoded.  I just added more missing documentation for working
around braindead senders that can't read an RFC to save their life:

# Treat these localparts as a DSN.  Lot's of braindead systems 
# send non-DSN mail to MAIL FROM.
;banned_users = mailer-daemon, clamav, postmaster

A DSN has a MAIL FROM of <>.  Any other MAIL FROM should never be
SRS decoded (except for the brain-damage workaround above).

I think we can make a case for rejecting non-DSNs to an SRS encoded
address with a stern rebuke (and RFC reference), rather than just
getting "invalid user".

-- 
 	      Stuart D. Gathman <stuart at gathman.org>
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.