domain/subdomain resolution

[Kevin Darcy]

Me wrote:

> hi all,
> i have a situation that seems a little bit weired to me:
>
> have 2 name servers: ns.mydomain.com and ns2.mydomain.com
> they both host the dna records for the same network and subdomains.
> today bind on ns.mydomain.com died. the ns2 is up. if i do :
> nslookup mydomain.com
> i get nonexistent domain

Well, where did that query go? Is the IP address of ns.mydomain.com the
first one listed in your /etc/resolv.conf? If so, then nslookup should have
failed over to the next address in the list. Does *that* nameserver have
any knowledge of mydomain.com? Apparently not. Should it? I have no idea. I
don't know how your DNS infrastructure is set up.

> if i do:
> nslookup mydomain.com ns2.mydomain.com
> it gives me the right information..
> the same with dig.
> my question is how the nslookup doesn't find the domain but it finds the
> ns for that domain?

nslookup's error messages are misleading. The "nonexistent domain" error
message doesn't necessarily mean that _everything_ in the domain is
unresolvable, it just means that the specific query you made (for an A
record (the default query type) called "mydomain.com") returned NXDOMAIN or
NODATA. Other records in the same domain might resolve just fine.

Furthermore, your queries presumably went to two different nameservers.
It's not terribly uncommon for nameservers to have inconsistent data for
the same domain name, although such inconsistencies are usually only
transient.


- Kevin