Forum Discussion
I think Josh is referring to the fact that when you create a wide ip in GTM configuration, it will automatically create a NS record for that domain using the hostname of the box. If you are not aware of this at the time you initially setup the GTM, you might end up using a hostname for that is tied to the management IP address in DNS. This of course results in an issue should anyone query your enterprise DNS servers for the NS records of that zone (the LDNS will cache the response from GTM and point the NS records at the management IP of the GTM which will timeout for all future requests if you are using CNAMEs for the wide ips).
Additionally, it seems in v10, the default behavior is to not synchronize the zone files between GTMs in the same sync group (whereas this was enabled by default in v9). As a result, if your LDNS queries GTM for type any or for the NS record, it will receive the single NS record that specific GTM had auto-created, reducing the high availability of GTM for that specific LDNS. To rectify, you must either enable synchronization of zone files in gtm configuration settings (under system), or manually create static NS entries to include the other GTM listener hostnames.
If your GTM deployment is using HA active/standby pairs (not best practice), this is further complicated by the fact that the floating listener address cannot be mapped to 2 separate A records, which means you must manually edit the NS records that were auto created in each GTM to point to the A record tied to that floating listener IP.