On 4/3/2012 9:56 AM, Sam Jones wrote: > Good Afternoon, > > My senior tech and I have been having a squabble over PTR, Hostnames and > reverse mapping. > > If you have a client connect from 1.2.3.4 and perform a host name lookup > on that, so you get back host.example.com, would it impact on mail if a > forward query for host.example.com returned multiple A records, say > 1.2.3.4 & 5.6.7.8 alternating between the top of the result sets in a > round robin?
It's possible, but the devil is in the details, which you did not provide to us. > I ask because we've seen an slightly odd pattern to some deferrals with > a host where this happens and wonder if they may be using: > > reject_unknown_client_hostname feature, which requires not only > that the address->name and name->address mappings exist, but > also that the two mappings reproduce the client IP address. > The unknown_client_reject_code parameter specifies the response > code for rejected requests (default: 450). The reply is always > 450 in case the address->name lookup failed due to a temporary > problem. This was included in your list welcome message. http://www.postfix.org/DEBUG_README.html#mail Please read it and post the relevant information it instructs you to. In this case, at minimum, we need to see the SMTP responses from the remote MTA. -- Stan
