3 ms·
So, do you require the PTR and A records of the remote host to match?
by Nux 10y ago
So, do you require the PTR and A records of the remote host to match?
- kazinator 10y agoI don't work with DNS at the protocol level; it's done via the Exim "verify = reverse_host_lookup". The documentation says: This condition ensures that a verified host name has been looked up from the IP address of the client host. (This may have happened already if the host name was needed for checking a host list, or if the host matched host_lookup.) Verification ensures that the host name obtained from a reverse DNS lookup, or one of its aliases, does, when it is itself looked up in the DNS, yield the original IP address. The phrase "or one of its aliases" seems to imply that the match does not strictly require the A record.
- jlgaddis 10y agoThe general term for this is "Forward Confirmed reverse DNS" (FCrDNS). I do these checks (plus others) on my Postfix mail systems. I would assume most of the other (sane) MTAs can perform these checks as well.