Maintained by: NLnet Labs

[Unbound-users] A Record Synthesis From Address-like Domain Names (dnscache behaviour)

Tony Finch
Fri Oct 7 14:24:44 CEST 2011

Jan-Piet Mens <jpmens.dns at> wrote:

> > for the benefit of MTAs delivering mail to MX records
> > containing IP addresses instead of hostnames.
> An MX record MAY not contain an IP address.

In fact it MUST NOT :-)

My mail servers (40K users) treat domains that are misconfigured this way
as invalid and it does not cause noticeable interoperability problems.

f.anthony.n.finch  <dot at>
Viking, North Utsire, South Utsire: Northwesterly 7 to severe gale 9,
decreasing 5 or 6 later. Very rough or high. Squally showers. Good,
occasionally poor.