On 7/1/2013 5:05 PM, LuKreme wrote: > > On 30 Jun 2013, at 06:05 , Wietse Venema <[email protected]> wrote: > >> LuKreme: >>> When reject_unknown_client_hostname triggers on an NXDOMAIN it >>> returns a 550 error, which is great. When it triggers because there >>> is no PTR record, it returns a 450 error, which is also great? >>> except. >> >> That is incorrect. The 450 code is for errors where lookup >> failed (no result instead of "does not exist"). > > Does not exist is NXDOMAIN, right? > > When the result is empty, like in this recent spammer: > > $ dig -x 208.84.134.170 | grep -A1 ";; Q" > ;; QUESTION SECTION: > ;170.134.84.208.in-addr.arpa. IN PTR > > postfix returns a 450. (Note, I'm not complaining about postfix's behavior) > > This IP has been failing with a 450 for weeks, but there are many.
http://www.postfix.org/postconf.5.html#unknown_client_reject_code
