====== Visual Studio Extension Manger Cannot Connect From Behind a Firewall ====== Recently had an issue where Visual Studio 2010 could not connect to the Internet while using the Extension Manager. I also could not connect to any remote NuGet servers either. I used Fiddler2 to see that Visual Studio was sending a header in each request that it expected a "100 Continue" response. I found somewhere on the Internet how to fix this by updating the devenv.exe.config file to tell Visual Studio not to expect the "100 Continue" response. A couple of days ago, one of my coworkers had the same issue. This time, I new what the problem was, but could remember the syntax... so I had to look it up on the Internet again. So, for the next time that I need it, I'm putting it here. Add the following to devenv.exe.config (in the Common7\IDE folder): This seems to be a known issue with some proxy servers and will be fixed in a future release; however, until then, I will continue to use this fix...