How To Tell When GTM Responds With iRule Address Or Fallback Address?

Out Enterprise DNS delegates A-Record responses for a particular Wide IP domain. My WideIP's Pool Member Fallback address is the default A-Record response. The WIP iRule contains the logic that if the DNS query is sourced from a particular address, a different A-Record is returned. How do I tell whether the WideIP is responding with it's Fallback IP address or with the address stated within the iRule? If I go to DNS>GSLB>Wide IP List> Select the Wide IP and go to Statistics, I do see

 

Requests:

 

Total 225

 

Persisted 0

 

A 155

 

AAAA 70

 

Resolved 155

 

Dropped 0

 

Load Balancing: Preferred 155

 

Alternate 0

 

Fallback 0

 

CNAME Res 0

 

Returned to DNS 11

 

Returned from DNS 0

 

I've also tried tcpdump -vv but the packets don't state what the GTM responds with, for the particular DNS queries.

 

Thanks for any/all help!

 

Mike