On Mon, 13 Jul 2009, Benny Pedersen wrote: > On Sun, July 12, 2009 22:47, Sahil Tandon wrote: > > On Sun, 12 Jul 2009, Keld Jørn Simonsen wrote: > > > >> >> Anyway if it is a name server timeout, then I think this is always > >> >> handled by a 450 response. In my case the mail was rejected. > >> > > >> > Yes, temporary errors always get a 450 response. > >> > >> Then I do not understand why the message was rejected. A temporary error > >> should not result in a reject, or why should this happen? > > > > A 450 response *is* a reject; > > defer not reject
An irrelevant semantic debate. See postconf(5); it is colloquially common to refer to these as *reject* codes. What matters is the numerical SMTP reply code and what it communicates to the client. > > the 4xx SMTP reply code tells the sending > > server to queue and try again later. > > correct, eg try until sending server have solved reverse dns (unknown) More generally, a 4yz response simply indicates a transient error, not necessarily one related to reverse dns. The client should try again. > > This contrasts with 5xx rejections > > which are permanent, > > one can argue we should not let the sender sever retry on missing reverse > dns, but it could as well also be errror in recieving side This (not letting sending server retry in case of DNS problems) would be a bad argument. -- Sahil Tandon <sa...@tandon.net>
