Fix - VS 2010 Extension Manager cannot see past firewall

In order to allow the VS.Net 2010 extension manager to check for updates, via a proxy server using your default proxy server entry, you need to add the following configuration to the devenv.config file.

Immediately after the <system.net> add the <defaultProxy…> entry as shown below.

    <system.net>

        <defaultProxy useDefaultCredentials="true" enabled="true">

          <proxy usesystemdefault="True" />

        </defaultProxy>

Full details available HERE.