Azure private dns second ip reverse lookup

Question

My host has 2 ips. Primary for the host, secondary for the application. running on Azure, setup the private dns. The primary ip can be reverse looked up fine. The second cannot. Tried setting up the in-addr.arpa domain and adding the reverse ips, no luck. Tried setting up the 120.10.in-addr.arpa domain and adding the reverse ips, no luck.

Is there a way to do reverse lookup on Azure with private dns for hosts with multiple ips assigned to the nic?

Extra info:

If this is my vnet range I would like to rev lookup

10.11.12.0/20

How would the domain look like?

0-20.12.11.10.in-addr.arpa

Or do I need to create separate ones per /24

12.11.10.in-addr.arpa

13.11.10.in-addr.arpa

14.11.10.in-addr.arpa

etc.

Thanks for you help.

Sander

Answer 1

First, make sure you have the following format: <IPv4 network prefix in reverse order>.in-addr.arpa for the private DNS zone.

For example, for the IP range 192.0.2.128/26, you must use 128-26.2.0.192.in-addr.arpa as the zone name instead of 128/26.2.0.192.in-addr.arpa.

Then, you could link your VNet to this private DNS zone, it allows your VNet to read the DNS resolution records.

Then, you could add the PTR record sets for each private IP address.

For example,

Test result:

Last but not late. Before this, you must manually add all the private IP addresses (including the primary) to a VM operating system. Refer here.