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 > 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) > 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 > i.e. mail is not queued/retried, but returned to sender. it can bounce whatever it does in remote, there is no control on the recipient host for this, forwards is not that cleaver if forwarded recipient does not accept it -- xpoint
