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Fix Slow Firefox 3 on Vista with localhost

Fix Slow Firefox 3 on Vista with localhost

December 23, 2008 4:41 pm10 comments

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)


  • Thank you! I would have never guessed that in a million years.

    I experienced the same problem and was wondering what to do.

  • Thanks man, saves me some loading time.

  • Thanks, I was getting ready to snap.

  • Gurdeep Singh

    Thanks a lot man :) I took myself helpless and had to use IE each time when there was localhost requests. You are a great help :) Thanks again.

  • hey man, u just saved me loads of nerves with my new laptop, thanks! it’s a pleasure working from home again.

  • James

    Is there any fix for the _web server_? I get this when using XML-RPC.NET as well. Unusably slow…

  • Georgee

    As we are on almost the same vein, can anyone tell me why when i first started to use Firefox with Vista it worked find but after a reload, Firefox 3.5.5 will not let me access or download a torrent from ANY torrent sites like isohunt, I get a popup window that says: firefox can not connect ,,,,, localhost:12322

    Anyone have this one?

  • Georgee

    Am I the only one in the world that cant get FF3.5.5 to download a torrent file from a fresh download of FF and a reload of vista?
    IE7 does it just fine.

  • Mitja Kukovec


    most probably the problem is in the firefox extension “Torrent Server Handler” by Alon Swartz. Uninstall the extension and everything should work just fine.

  • Ed Mansfield

    That’s amazing! Thank you, thank you…
    When I consider all the time I’ve spent watching and waiting for that GD progress bar to finally complete so I can run another test round… Ahhhh