[Mimedefang] OT: DNS sanity check

[Graham Murray]

Les Mikesell <les at futuresource.com> writes:

> It can be very difficult to get right, considering that the naming
> authority is delegated through different entities for the forward and
> reverse lookups, and you may need multiple A records for a given name
> and often also need multiple names for a given IP since it may be
> doing something in addition to email or handling multiple domains.

Multiple names do not matter. All is OK as long as the connecting IP
address is one of the IP addresses to which the A record pointed to by
the PTR record for the connecting IP address resolves.