Have a strange issue at the moment, HTTPS website bypassing proxy is experiencing a 12 sec delay from SYN hitting Internal TMG interface to being output through the TMGs Outside interface.
Subsequent packets for the connection are fine including SYNs for new connections but if left for approx 5 mins, 12 sec delay for next SYN.
TMG Logging shows packet experiecing a 12000ms Processing Time compared to 0ms when not delayed, either way logging shows Success.
URL Filtering is disabled, HTTPS Inspection is disabled, Malware Inspection is disabled, site in NIS exemption, site in Flood Mitigation exemptions, manual DNS lookup of address on TMG always completes instantly, logging shows not being blocked, CPU/Mem are fine.
This only appears to be happening to this one site but is causing a deal of frustration on a critical app - would greatly appreciate any suggestions.
Server: 2008 R2 Enterprise 64bit
TMG: 7.0.9193.500 (TMG 2010 SP2)