This is a strange one. Connectivity to Office 365 within our netwotk works fine although very slow for outlook 2010 client to initially connect. Once connected, it works ok. I have done a netwotk trace using netmon to see if i can identify the reason for the slow startup (2 mins minumum for profile to load and for outlook to connect to exchange). The trace tell me that my local pc tries to make a direct connection to the office365 external IPs first, then tries the TMG proxy. Once it hits the proxy, it kicks into life and works.
So it looks to me like it thinks the external IP address of office 365 is an internal address and spends it time trying all the ip addresses until it trys the proxy. At this point, theBypass Proxy Server for Local Addresses is ticked.
As soon as i untick this box, all traffic heads directly to the proxy and of course it connects like lighting. The exchange settings proxy is set in outlook for "on fast networks, connect using HTTP first, then connect using TCP/IP" (tick is on) and the same for slow networks.
I cant for the life of me work out why it tries to connect directly to the external IPs first and not connect via TMG until i untick theBypass Proxy Server for Local Addresses
Would love any ideas that may assist.