On Thu, Feb 16, 2012 at 05:06:22AM -0800, daniel zhou wrote: > The document segment about the reject_unknown_sender_domain says > that it will reject the domain without A record or MX record. Does > it mean that only domains with both A and MX record will be > accepted? Or, it means any domains with only A record,domains with > only MX record or with both will be accepted. Can anyone clarify > it? Thanks!
An unknown sender domain means that the name did not resolve in a way such that mail could be delivered to it. An A record, even if it's 0.0.0.0 or 127.x.x.x or any other address that might not be deliverable for some reason, qualifies as a "known" sender domain. Unless of course there is a MX, and that name does not resolve: then it is unknown. Also a malformed MX record is "unknown". IIRC these rules can be found in RFC 5321 and predecessors. > I just want to block the senders whose domain without MX record, > even if it has an A record. There is check_sender_mx_access, but I don't know if it strictly works the way you want. Also, I don't think your idea is a good one. You will block some real mail, I bet, while making little if any impact on spam. -- http://rob0.nodns4.us/ -- system administration and consulting Offlist GMX mail is seen only if "/dev/rob0" is in the Subject:
