I got a complaint from a client that postfix is returning a "5.0.0" DSN
when emails are sent to an unknown user. I believe this is to prevent
backscatter. In any case, it appears this 5.0.0 DSN response is hard coded
into the error daemon?
From my logs I see:
Oct 1 13:11:07 zre-ldap002 postfix/smtp[8257]: 000501E37BC:
to=<badu...@zre-ldap002.eng.vmware.com>, relay=127.0.0.1[127.0.0.1]:10026,
delay=0.22, delays=0.03/0/0/0.19, dsn=2.0.0, status=sent (250 2.0.0 from
MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as 2D0711E37BE)
Oct 1 13:11:07 zre-ldap002 postfix/qmgr[23910]: 000501E37BC: removed
Oct 1 13:11:07 zre-ldap002 postfix/error[8324]: 2D0711E37BE:
to=<badu...@zre-ldap002.eng.vmware.com>, relay=none, delay=0.06,
delays=0.03/0/0/0.02, dsn=5.0.0, status=bounced (zre-ldap002.eng.vmware.com)
And in the source I see:
if (strcmp(service, MAIL_SERVICE_ERROR) == 0)
status = deliver_message(request, "5.0.0", bounce_append);
The client would rather have 5.1.1 returned, so they can integrate it with
a Sophos Email Appliance, which is apparently expecting the 5.1.1 response.
I assume there is an easy way to change this behavior I'm just missing. ;)
I checked the postconf reject codes, and I don't see 500 set anywhere. I
have:
unknown_local_recipient_reject_code = 550
unknown_relay_recipient_reject_code = 550
Thanks for any pointers. :)
--Quanah
--
Quanah Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
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