Domain resolution problem.

[Kevin Darcy]

There's two problems here:

1) One of the delegated nameservers for the nbb.co.jp zone --
gatekeeper.nomurababcock.co.jp -- is not responding to queries.

2) The NS'es in the nbb.co.jp zone do not match the delegation NS'es: in
fact, the only NS reported by the only working nameserver for nbb.co.jp is
gatekeeper.nbb.co.jp, with the same address as the other, non-responding
"gatekeeper". Because the NS'es are wrong, other nameservers may expire the
mailguard.nbb.co.jp A record out of their caches and then not be able to
resolve it again until the NS record also expires and they get a fresh set
of delegation NS'es from the co.jp nameservers. Since the TTL on the NS is
a day, this can mean multiple-hour delays. Note that even if
"gatekeeper" were working, the bad NS records could result in deadlock, if
the A record happens to expire from the cache before the NS record does.
The permanent fix is to make the zone NS'es match the delegation NS'es.


- Kevin

Ali Eghtessadi wrote:

> I am having a problem resolving the domain "mailguard.nbb.co.jp" using
> the internal dns servers in our network. The internal DNS servers are
> unable to resolve it and then after a few days they can resolve this
> domain again. This is causing the email flow between our offices to
> fail. I also have a dns server which is outside the firewall and is the
> primary for domain babcockbrown.com, this dns server can resolve the
> mailguard.nbb.co.jp with no problem.
>
> Any idea what the problem may be? I can provide a copy of our db file if
> that helps. Please let me know and any help is very much appreciated.
>
> Ali