New session in IE 11

Under the "File" menu in Internet Explorer 11 in addition to "New tab" and "New window" lies "New session" and this third option will open a new window with, yes, a new session. If you are testing through an IIS proxy server and the proxy server can route to one of three IIS webservers, you might disable two webservers (make the AppPool for each unavailable) to ensure that you hit webserver A when hitting the proxy server and then make a second pass through to webserver B with A and C disabled. When you make the switchover, it might be wise to use the "New session" trick to get rid of any A-record-to-IP-address association lingering.