I came across a weird issue today with my ASP.NET Dev Server. I’m running Vista Home Premium with Firefox set as the default browser. I was consistently getting a “Failed to Connect: Firefox can't establish a connection to the server at localhost:<port>.” error. Little bit of Goolge pointed me to several posts suggesting that I turn off IPV6 on my network adapter. Hmmm… Nope! I know a better way to fix this (fingers crossed). Navigated to %SystemRoot%\system32\drivers\etc (C:\Window\system32\drivers\etc on mine). Opened up hosts file in notepad. Commented out the following line:

::1             localhost

It now it looks like

#::1             localhost

Save the file, restarted Firefox and Dev Server (not sure whether I needed to even do that). Presto! It works!