Delegating reverse DNS to a customer

[Chris Hills]

On 18/08/09 15:55, Ben Bridges wrote:
> Since the CIDR block you have been allocated containing 63.250.251.0/24
> is smaller than a /16, ARIN is delegating authority for the IN-ADDR.ARPA
> zones for each of your /24's directly to your dns servers. In order for
> your customer's dns servers to be authoritative for
> 251.250.63.IN-ADDR.ARPA, you're going to have to have ARIN delegate the
> zone to your customer's servers. If you have not already SWIP'ed the /24
> to your customer, then you'll want to do so using the detailed
> reassignment template
> (https://www.arin.net/resources/templates/reassign-detailed.txt, I
> think). If you have already SWIP'ed the space to them, then you'll need
> to submit the net-mod template
> (https://www.arin.net/resources/templates/netmod.txt, I think) for the
> /24. (Note: I'm not the person who submits SWIP templates in our
> organization, so I might be wrong about the particular templates to use.
> But the principle is still valid. It's the SWIP information filed with
> ARIN that determines what dns servers are authoritative for the
> in-addr.arpa zones for your /24's.)
> Ben

Alternatively it is possible to delegate it using the CNAME trick used 
for sub-/24 allocations, which will require 256 dns records that can be 
made using $GENERATE.

For example:-

$TTL 86400
$GENERATE 0-255 $ IN CNAME $.0-255.251.250.63.in-addr.arpa.
0-255.251.250.63.in-addr.arpa. IN NS ns1.emns.com.
0-255.251.250.63.in-addr.arpa. IN NS ns2.emns.com.
0-255.251.250.63.in-addr.arpa. IN NS ns3.emns.com.
0-255.251.250.63.in-addr.arpa. IN NS ns4.emns.com.

Then the customer will need to configure the zone 
0-255.251.250.63.in-addr.arpa. as if it were 251.250.63.in-addr.arpa.

Regards,

Chris