Forwarding reverse DNS queries

Kevin Darcy kcd at daimlerchrysler.com
Thu Nov 20 22:26:19 UTC 2003


Thomas Smith wrote:

>A customer of mine is having issues with their reverse DNS. The 
>situation is this:
>
>They lease a block of IPs from me. The customer has his own DNS servers 
>(two of them). Forward lookups work fine, but reverse lookups don't work.
>
>I understand what the problem is--reverse lookups are being directed to 
>my servers since I own the IP block in question.
>
>The question is: How do I forward reverse DNS lookups for a specific 
>block of IPs to his servers?
>
If the block is /24 or larger, then just delegate the relevant reverse 
zones to his servers.

If the block is /25 or smaller, then read RFC 2317. Note that the RFC is 
only a BCP and you don't have to follow it slavishly: you and your 
customer have considerable latitude over where the PTRs will live; they 
could even live in "forward"(non-"in-addr.arpa") zones if you would find 
that convenient...

- Kevin




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