On Wed, 14 Aug 2019, Wietse Venema wrote: > > One of our users reported a rejected email with the error code and > > message > > > > Remote-MTA: dns; artemis.gat.com > > Diagnostic-Code: smtp; 550 Sender IP reverse lookup rejected > > > > We handle several domains with different outgoing smtp settings at > > multiple mail gateways: > > > > # /etc/postfix/master.cf > > wignersmtp unix - - y - - smtp > > -o smtp_bind_address=148.6.0.56 > > -o smtp_bind_address6=2001:738:5001::56 > > -o smtp_helo_name=smtp.wigner.mta.hu > > -o syslog_name=postfix-wigner-smtp > > > > # /etc/postfix/main.cf > > default_transport = kfkismtp > > sender_dependent_default_transport_maps = > > hash:/etc/postfix/sender_transport > > > > # /etc/postfix/sender_transport > > @wigner.mta.hu wignersmtp: > > ... > > > > The sender address was from the @wigner.mta.hu domain and the IPv4/IPv6 > > addresses resolve to smtp.wigner.mta.hu. The HELO name is also explicitly > > set to this name. Using debug_peer_list I could verify that the wignersmtp > > transport setting is used for @wigner.mta.hu senders indeed. > > > > So, what kind of incorrect setting can the "Sender IP reverse lookup > > rejected" error message be mean? > > It could be the same problem as GMAIL, where they would do a hard reject > after a temporary error during reverse DNS lookup. > > At the time (years ago) I just turned on "-o soft_bounce=yes" for those > deliveries, so that the email would be delivered later. > > Of course, soft_bounce is not ideal; nowadays I would use > smtp_delivery_status_filter to change the 5.*.* into 4.*.* for that > specific server response. > > If the result of this is that mail stays in the queue, then > further investigation will be needed.
It seems it's a persistent problem. I tried to contact the postmaster at the other side but of course got the same reject. We'll try to contact them via a third party. Thank you to remind me about smtp_delivery_status_filter, it can come handy in other cases! Best regards, Jozsef - E-mail : kad...@blackhole.kfki.hu, kadlecsik.joz...@wigner.mta.hu PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences H-1525 Budapest 114, POB. 49, Hungary
