Understanding GTM Wide IP Operations

Muhannad That seems right to me based on some assumptions.

gtm work like you say,  if the dns profile of the gtm dns listener does not disable the dns bind function, wideip fallback mothod set to Return to DNS, if all gtm pool members down, it will use dns bind round-robin to response dns request

If you are not clear, you can apply for 30 days trial BIGIP-VE，Do experiments to simulate some extreme scenarios, such as：

1. disabled wideip, will it cause fallback method Return to DNS, work use dns bind function ok ?

2. althernatte method set to None, fallback method to None, when all gtm pool members down, does gtm return to dns response?

3.disabled gtm pool or disabled gtm pool all members, or disabled gtm server virtual server, what will gtm work?