GTM DNS Question

You shouldn't have to CNAME anything. I've used Link Controller quite a bit and that's pretty similar to GTM. I'd simply do a setup like this:

 

 

1. Floating listener IP on GTM of 1.1.1.1 (obviously replace this ip)

 

2. A-record in your DNS zone (let's assume example.com) in this case "gtm-listener IN A 1.1.1.1" (obviously use your own name/ip combo)

 

3. NS record for "www.example.com" would be "www IN NS gtm-listener"

 

4. Wide-IP configured on GTM to map www.example.com to whatever VSes you need.

 

 

Make sense?