Question about Reverse mapping name servers

David Nolan vitroth+ at
Wed Oct 3 22:11:53 UTC 2007

--On October 3, 2007 5:45:54 PM -0400 "Reedy, Sean" <sreedy at> 

> Sorry if I caused confusion.  I'm going to be the "Delegator" and didn't
> know how to do that with Bind.
> ARIN is asking what two name servers will be used to provide Reverse IP
> lookups for the addresses they are going to assign me.  I have two
> servers, but wasn't sure if I could host the if my name
> servers didn't have IP addresses in the block of addresses that ARIN
> assigns.
> Is there a How-to for hosting reverse lookup?


In general are no restrictions on what IP space a server needs to be in to 
be able to have forward or reverse zones delegated to it.  There are some 
TLDs that provide the ability to restrict delegations to servers within 
that domain, but I don't believe the same is true for IP ranges.

You might want to start by reading some basics on how delegations & reverse 
lookups work, such as the info in the DNS & Bind on the site: 

If you need to take portions of the IP space thats assigned to you and 
delegate it to another set of servers how you do so depends on the size of 
your address space and the size of the delegation.  That site has some 
basics, but doesn't have a thorough set of "in case A you delegate with 
method B" examples.  If you post something describing your exact scenario 
better we can probably give you some options.

-David Nolan
 Network Software Designer
 Computing Services
 Carnegie Mellon University

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