Some DNS names won't resolve

I'm running SME server, which is built on Redhat 7.3. It is a
self-contained, small-business solution and has been working well for
us.

Recently, we hired an outside accountant and now we've begun to notice
problems. We can't send e-mail to him because our DNS server can't
locate his DNS servers and find an MX record for his company. All the
other sites we work with have given us no trouble.

I would say the problem is on his end, but if I run dig against our
ISPs DNS or a freind's DNS, the names resolve immediately. It's just
this site and one other (Tracfone.com) that we can't resolve without
hosts entries, and that doesn't help much with MX lookups.

I've tried disabling all firewall rules, and still no dice. An ethereal
scan shows records being returned from the root servers for his
servers, but we just can't seem to connect to them on port 53 while
obviously other people do. I have run dig with a 30-second timeout
value and still get nothing.

What am I overlooking?

-RR

(E-Mail Removed) wrote:
> I'm running SME server, which is built on Redhat 7.3. It is a
> self-contained, small-business solution and has been working well for
> us.
>
> Recently, we hired an outside accountant and now we've begun to notice
> problems. We can't send e-mail to him because our DNS server can't
> locate his DNS servers and find an MX record for his company. All the
> other sites we work with have given us no trouble.
>
The universe is telling you this might not be the right accountant?

> I would say the problem is on his end, but if I run dig against our
> ISPs DNS or a freind's DNS, the names resolve immediately. It's just
> this site and one other (Tracfone.com) that we can't resolve without
> hosts entries, and that doesn't help much with MX lookups.
>
> I've tried disabling all firewall rules, and still no dice. An ethereal
> scan shows records being returned from the root servers for his
> servers, but we just can't seem to connect to them on port 53 while
> obviously other people do. I have run dig with a 30-second timeout
> value and still get nothing.

If I read this correctly, you *do* get the A records pointing to
whatever the name server for his domain is, but can't do any lookups on
them.

A few things to try:

(1) dig <hisdomain> MX @<ip-of-his-NS>
(2) ping <ip-of-his-ns>
(3) traceroute <ip-of-his-ns>

If you can ping the nameserver, but can't get it to resolv things for
you, ask someone else to run a dig MX against it, and (assuming that
that works), carry on looking for firewalls.

>
> What am I overlooking?
>
> -RR
>


--
Mail to (E-Mail Removed), bearing in mind that .za only knows about .co.za

On 18 Mar 2005, (E-Mail Removed) <(E-Mail Removed)> wrote:
> I'm running SME server, which is built on Redhat 7.3. It is a
> self-contained, small-business solution and has been working well for
> us.
>
> Recently, we hired an outside accountant and now we've begun to notice
> problems. We can't send e-mail to him because our DNS server can't
> locate his DNS servers and find an MX record for his company. All the
> other sites we work with have given us no trouble.
>
> I would say the problem is on his end, but if I run dig against our
> ISPs DNS or a freind's DNS, the names resolve immediately. It's just
> this site and one other (Tracfone.com) that we can't resolve without
> hosts entries, and that doesn't help much with MX lookups.

You do not say what the troublesome domain is, but 'dig tracfone.com mx'
was a bit sluggish for my DNS in SuSE (bind9) Query time: 4134 msec (over
4 seconds) at a non-busy time of day (early AM). So nslookup in Windows
XP would have failed first attempt (gives up after 2 seconds by default).
Although, a second try (from DNS cache) would work. DNS for this domain
appears to be correct, but is unknown for the other unknown domain.

(E-Mail Removed) (David Efflandt) wrote in
news:(E-Mail Removed):

> You do not say what the troublesome domain is, but 'dig tracfone.com mx'
> was a bit sluggish for my DNS in SuSE (bind9) Query time: 4134 msec (over
> 4 seconds) at a non-busy time of day (early AM). So nslookup in Windows
>

I just did a dig tracfone.com mx on my FC2 box with Bind9 and the query
took 54ms (4:30AM Eastern).