iptables blocks update for Microsoft Essentials

Question

Please advise which ports/destinations shall be opened at the Linux firewall to allow MS Essentials updates for Windows PCs.

Answer 1

Problem was with the way MSE works with proxy. To my surprise, it does not simply takes proxy settings from IE, but requires magic command (for Windows 7):

netsh winhttp import proxy ie

Details here.

Even though my proxy was set in transparent mode and above command reports that direct connection is used.