question

Hello @davidnithil-0883, Welcome to the Microsoft Q&A forum.

Based on my understanding of the question. You have an internal load balancer (ILB) deployed in a Vnet and now you want to add a Private DNS record for the private frontend IP configured for your ILB.

If my understanding here is correct. Yes, it is possible to add a Private DNS record for the private frontend IP configured for your ILB. As documented here, you will have to create DNS records manually for your ILB as the record will not get auto-generated.

I tried a similar set-up and was able to add a DNS record for the Frontend IP of my ILB, as shown below.

In my private DNS zone named internal.net I added a type A record named eus2 pointing to my ILB's frontend IP.

I did a Nslookup from my backend Vm and was able to resolve the FQDN for my ILB.

If yes should we add dns to frontend ip/ full name of the loadbalancer like eus2.internal.net

I am not sure if I have completely understood this part of the question. Based on your naming convention you can add any custom domain names in Azure Private DNS Zone as long they have two or more labels.

Hope this helps! Please let me know if you have any additional questions. Thank you!