GTM and Wide IPs

Here is what you can do.

Say that your DNS servers are authoritative for example.com domain and it answers for all queries for example.com domain. Say you need the GTM to hand out DNS requests for forward.example.com.

Create a new domain wip.example.com and make the GTM authoritative for this new domain (Create a new Zone record in Zonerunner for wip.example.com domain - This will create a new SOA record and a NS record on the GTM).

Create new CNAME entry for forward.example.com which points to forward.wip.example.com on the regular DNS.

forward.example.com CNAME forward.wip.example.com

Create a new WideIP on the GTM for forward.wip.example.com

At this point any DNS query for forward.example.com that a client asks for will eventually end up at the GTM.

What happens:

1. Client asks regular DNS for forward.example.com

    

2. DNS server has a CNAME pointing to forward.wip.example.com

    

3. DNS server knows that GTM is authoritative for the wip.example.com domain

    

4. DNS sends a request to the GTM for forward.wip.example.com

    

5. GTM responds back with the IP for forward.wip.example.com to the DNS server

    

6. DNS server responds back to the client with the IP address

    

Note: In this scenario the GTM is going to see the DNS server as the source of the DNS query and not the actual client machine.