Maintained by: NLnet Labs

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

Sabahattin Gucukoglu
Fri Oct 7 16:31:47 CEST 2011

On 7 Oct 2011, at 13:24, Tony Finch wrote:
> 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.

I think one of my earlier users may have turned to me for help precisely *because* your servers would not relay his mail. :-)

At any rate, fair enough, I'll just wait for the bounces to come in, and see how bad the problem really is.  I only serve a few users (about 10) and many of them aren't non-English speakers natively which is where the problems really seem to be, with custom software running somewhere in the east.