strange resolver behavour

[Tom Evans]

On Tue, Oct 12, 2010 at 10:05 AM, Ian Smith <smithi at nimnet.asn.au> wrote:
> On Mon, 11 Oct 2010, Eugene Grosbein wrote:
>  > Hi!
>  >
>  > FreeBSD 8.1-STABLE:
>  >
>  > # host koin-nkz.com.
>  > koin-nkz.com has address 62.231.164.101
>  > Host koin-nkz.com not found: 3(NXDOMAIN)
>  >
>  > This domain does not have MX records but NXDOMAIN seems to wrong return
>  > code to me. Think about MTA that does look-up for MX first,
>  > obtains NXDOMAIN and rejects mail.
>
> If a domain has no MX server, how's an MTA supposed to do mail with it?
>

The same way as has been done since they invented the MX record type -
if no MX record exists, fallback to an A record. See RFC 5321, section
5.1.

Cheers

Tom