Aaron Wolfe a écrit : > Hello, > > We use reject_unknown_client to fail messages from hosts with no rDNS. > We have a situation with the host 216.163.249.229, which give the > following results: > > > NOQUEUE: reject: RCPT from unknown[216.163.249.229]: 450 4.7.1 Client > host rejected: cannot find your reverse hostname, [216.163.249.229]; > > There actually is reverse DNS for this address... 239 PTR records! >
and some of these do not resolve. $ host ms.metaproposreq.com Host ms.metaproposreq.com not found: 3(NXDOMAIN) $ host ms.methyattnotices.com Host ms.methyattnotices.com not found: 3(NXDOMAIN) ... so if one of these is returned as the first PTR, the forward lookup won't return the original address, thus "unknown". That's one reason why multiple PTRs are bad. They only create problems. > using 'host' returns them all, with a warning: > > ;; Truncated, retrying in TCP mode. > .. and then all the results > > So I guess the result is so large that UDP cannot contain it, and > within postfix the TCP method either isn't being tried or isn't > working. Is this a problem with my resolver or something I can fix in > postfix? The lookup does work on this machine using 'host' with the > above error. >
