pigrace I’ve noticed that Firefox 3 is insanely slow loading web pages on localhost when using the ASP.NET Development Server (based on Cassini). Today something snapped in my head and I felt compelled to figure out what was wrong.

Everything was fine in IE7 and when connecting to the production web server from FF3. A few seconds plus a search engine revealed a simple solution:

  1. In in the Firefox address bar, type about:config and hit Enter.
  2. Click the "I’ll be careful, I promise!" button.
  3. In the Filter box, type network.dns.disableIPv6.
  4. Toggle the value of the network.dns.disableIPv6 setting to true.

That fixed the problem instantly for me. Hooray!

(photo courtesy of larry&flo)