External VS and internal pool members port 80 issue

Like Hamish suggested, it seems like something after the DMZ LTM is doing port translation. You can use tcpdump to verify LTM is sending the request to the pool members on port 80 and then use tcpdump on the internal LTM to see if the request is making it there. If see packets leaving the external LTM but not arriving on the internal LTM, it's probably something in between blocking it.

 

 

Aaron