why nslookup could not find my domain?

[Kevin Darcy]

TAT LUK wrote:

>         I am running BIND-4.9.7 on an NT 4.0 platform. Both
>         the forward and reverse lookup tables are setup
>         correctly. From my network, when I do a ping to a host
>         within my network, it works fine. When I do a nslookup with
>         the same address, it works fine also.
>
>         When I try it from an external ISP and use
>         their DNS, pinging to the same host has no problem, yet
>         nslookup for that address failed to resolve the host name.
>         If I force the nslookup to use my DNS, then both ping and
>         nslookup will work from the external ISP. Is there
>         any reason why nslookup does not work for me from the
>         external ISP (or the Internet)?
>
>         I also noticed that there is a form called "in-addr.arpa"
>         registration form from Internic. I understand it is for reverse
>         address lookup but can someone help me to better
>         understand the purpose of this form and what would
>         happen if I have never submitted this form for our domain?

Unless your reverse DNS data are delegated/aliased properly, then no-one
will know to ask your servers about them. You should contact your network
provider about getting this set up. If you have a /24 or larger, then you
need to have one or more in-addr.arpa zones delegated to your servers. If
you have something smaller than a /24, then you need to have individual
addresses delegated as zones to your servers or aliases created (see
RFC 2317 for a general explanation of how the aliasing approach is
implemented).


- Kevin