Re: IN ADDR-ARPA entries
Tue, 2 Dec 1997 08:53:38 -0500 (EST)

I ask forgiveness in advance for this off-topic dns stuff.

On Fri, 28 Nov 1997, rkm wrote:

> I am confused about reverse lookups. I understand that not unlike domain
> registrations there are two components, the record with the InterNic root
> servers and the entries in primary DNS. Let's assume that I have a class

Buy (and read) DNS & Bind. You need to understand DNS!

> "c" assigned to me, 209.45.179.XXX and a domain of that is the
> basis for my operations. So if I make the entry based on that all reverse
> lookups will point to that domain. Now let's assume that I multihost a

The inverse mapping (what you call reverse) has nothing to do with any
domain name. Forward delegation happens when you register a domain with
the internic. Reverse delegation does NOT happen when you are assigned a
block by your provider...You have to ask.

The first thing you should do is to find out whether your nameservers are
authoritative for the reverse DNS for your c-block. To do that, you use

Run nslookup and at the prompt enter "server"
Then enter "" (note the '.' at the end!)

The answer is ...

Served by:
- NS2.LCI.NET you don't have to worry about reverse dns at this point, because
nobody will ask your nameservers about 209.45.179/24. You have to contact if you want to make your nameservers authoritative for 209.45.179.

> bunch of virtual domains for web customers and email. Let's say that .75
> thru .100 are domains other than
> What do I do about reverse lookup entries for those domains? Does it
> matter?

Sorry to be so long-winded. The answer is that webservers, real or
virtual-host, don't usually need inverse mapping. Clients (like web
surfers) ask your servers for the IP address of They
don't ask for the name of