Mail Routing Issues

[Antony Stone]

On Tuesday 16 September 2003 2:48 pm, Jason Burzenski wrote:

> I don't know what the actual records look like but I can tell you what the
> MX query returned.  "Canonical name = www.b.com"

Is it possible that the MX record has been pointed to a machine with a CNAME
instead of an A record?

If so, this is explicitly disallowed, and would cause all sorts of problems.
However, I hope you are not dealing wiht a DNS admin who would do that?

> So if I were to nslookup, set type=mx, b.com, it would return some soa
> record information and then that canonical name statement.

Sounds to me like it's the above.

Dig (or nslookup if you're still using that) for MX should always return an A
record for the mail server/s.

> I asked the admin of the DNS server to change the record to respond with
> what I was getting from a.com and c.com which looks like: *** Can't find
> b.com: No answer

I don't understand.   What did you ask them to do?

> As soon as this change was made, the messages started being sent to
> user at b.com again instead of user at www.b.com and everyone was happy.
>
> Now b.com is responding with Can't find b.com: No answer from an MX record
> query and everything is working well but I cant seem to figure out why that
> happened.

Unless you are particularly paranoid about telling this list what your
domains are, maybe post the real names for a, b and c and we can do a bit of
DNS lookup ourselves to see if it looks like there's a problem somewhere?

Regards,

Antony.

--

It is also possible that putting the birds in a laboratory setting
inadvertently renders them relatively incompetent.

 - Daniel C Dennett