Issue: Windows update fails with error 80072f8f on TMG server.
Scenario : Admin was trying to do windows update on the TMG server and it was failing with error 80072f8f.
Troubleshooting Approach and Resolution
1. We know windows update uses http , so first checked the browser's proxy settings , if its configured with a proxy or not if yes then is it using itself as proxy or some other device/machine as a proxy. We found that browser was configured with proxy settings and proxy was a third party server.
2. Tested internet access i.e tried to access bing.com without proxy in the browser, we had a test access rule on TMG server to allow access between localhost and external for http Our test gave us page could not be displayed. Then tested with TMG server as proxy server, that failed as well, then tested with the proxy server that customer was using and we got the page prperly.
3. That explained that TMG server could not access internet directly and we have to configure webchaining making the third party proxy server as the upstream proxy server. Then after configuring web chaining we tested by trying to do windows update and it worked.
Reference about how to configure webchaining : http://technet.microsoft.com/en-us/library/cc984471.aspx