Customer requested to create an LB for their AD DNS, I know querying records will work just fine, but what about dynamic updates for the workstations (https://learn.microsoft.com/en-us/windows-server/networking/dns/dynamic-update)? Does it require something special? I set up both DNS and DNS_TCP type vServers for the same IP. It seems next to impossible to find any information how the update happens on protocol level.

Unless you are setting up the NetScaler to be authoritative DNS it is just going to send all the requests through the system.

@Jeff Riechers, so it's going in the DNS protocol to the AD DNS server?

It is UDP. You can prove it easily by executing an ipconfig /registerdns. I just did. It is nothing other than a SOA query for hostname.mydomain.tld and the response is the SOA record, the A record and the AAAA record. It is a pure RFC compliant protocol stuff and NetScaler does not interfere in any way.

thank you!

That's the trace.

Someone once told me they understand DNS and its simple. Haven’t stopped laughing since!

I've been load balancing AD DNS since I first learned NetScaler (I think firmware 8 or 9). No problems with domain registration I've come across.