I recently moved from ISA 2006 to TMG. Since switching over to TMG, there is a significant performance issue when browsing the web from the clients behind TMG. Whenever opening a browser, it takes a 2 to 5 seconds before the intial page appears. Browsing this page, however, is as fast as it used to be with ISA 2006. Whatever link within the same FQDN will respons as normal. If I open a link on to different FQDN, it will again take a few seconds for the page to appear.
There are no performance issues with this server, there is no packet loss and downloading files is as fast as ever.
It seems TMG is checking the requested URL domain for its validity. This is taking an unacceptably long time. How do I circumvent this? I already tried disabling the Network Inspection and malware protection.
Any sugestions on where to look for this issue would be appreciated.