Imagine that you have a reverse DNS domain configured within Ultra for the IP block 22.214.171.124/24.
It will look like 3.2.1.in-addr.arpa. Now suppose someone on the network team wants direct control over a smaller block of IPs delegated to DNS servers onsite called ns1.reversetest.com and ns2.reversetest.com.
How can 126.96.36.199/32 be delegated away from UltraDNS?
1. Create a CNAME for 188.8.131.52 so recursive servers know what its new name is.
Two naming conventions are available (45/184.108.40.206.in-addr.arpa and 45-220.127.116.11.in-addr.arpa). The convention used within the /24 MUST be replicated for the /32 elsewhere.
For this example we will use 45/32. The CNAME would appear as:
18.104.22.168.in-addr.arpa 86400 IN CNAME 45.45/22.214.171.124.in-addr.arpa
2. Create NS records within the 3.2.1.in-addr.arpa domain to delegate control of the /32 over to third-party name servers.
They will appear as:
45/126.96.36.199.in-addr.arpa 86400 IN NS ns1.reversetest.com
45/188.8.131.52.in-addr.arpa 86400 IN NS ns2.reversetest.com
So anyone doing a reverse query for IP 184.108.40.206 will first receive the CNAME response adding /32 onto the hostname then they discover that this particular PTR resides on the reversetest.com name servers and go there for the end result.
Always remember to add the final octect value onto your PTR record(s) within the classless zone.
If we used a larger block like 45/220.127.116.11.in-addr.arpa there would be PTR hostnames such as:
46.45/18.104.22.168.in-addr.arpa 10800 IN PTR mail.domain.com
47.45/22.214.171.124.in-addr.arpa 10800 IN PTR mail2.domain.com