Alex: > Hi, > > I'm wondering about some messages with Received headers such as this: > > Received: from zaphod.chipchaps.com (unknown [65.182.186.13]) > > It says 'unknown', but 65.182.186.13 does resolve, to chipchaps.com (a > spam site), which resolves back to 65.182.186.12. Is this where the > problem is?
The definition of an "unknown" client hostname is given in http://www.postfix.org/postconf.5.html#reject_unknown_client_hostname which, as the name suggests, rejects mail from a client with a hostname that Postfix considers "unknown". Wietse > I'm not sure if I'm having a DNS problem with my resolver not being > able to find the answer in time (or at all), or I'm possibly not > understanding how to do this properly. I'd like to determine if I can > add additional restrictions in postfix to limit connections from hosts > that don't resolve properly, but before I can do that I need to make > sure my DNS is working properly. Maybe I'm able to resolve it now but > wasn't able to when the email arrived? Maybe the DNS info has changed > since the email was received? > > What are the risks or implications of denying messages of this type? > > Thanks, > Alex > >
