Last post Nov 04, 2010 11:35 AM by schadeux
Jan 22, 2007 04:17 PM|tom.frey|LINK
I'm having a very strange issue that I'm experiencing ever since I installed Vista (this problem occurs even after a clean install of Vista). When I'm developing an ASP.NET website running it on the VS ASP.NET development server, the page loads exceedingly
slowly in Firefox only. A page refresh sometimes takes up to 5 seconds (we're talking localhost here). Also, although both IE and Opera load sites significantly faster than Firefox, it's still slower than on XP. On XP page refreshes used to be instant, now
they even take 1-2 seconds on IE.
Jan 23, 2007 03:30 AM|blumonde|LINK
Jan 23, 2007 07:56 AM|tom.frey|LINK
Jan 31, 2007 09:26 AM|watersjohn|LINK
This is caused (in part) by a combination of a feature of Vista's new TCP stack and hardware between you & the development server.
To fix this, open an elevated cmd prompt, and type "netsh interface tcp set global autotuninglevel=disabled"
For more information, see
Jun 25, 2007 10:23 PM|ghotiman|LINK
I found the answer here:
In Firefox, goto about:config, filter by "network.dns.disableIPv6" and double-click to set to true.
Jul 03, 2007 06:20 PM|timcharper|LINK
that fixed it for me. Thanks!
Jul 04, 2007 05:47 PM|kbeeveer46|LINK
Thanks a lot. This "slowness" has been bugging me for over a month.
Jul 04, 2007 06:56 PM|blumonde|LINK
I have FF v2.0. I couldn't find about:config, filter by "network.dns.disableIPv6" anywhere. Where is it supposed to be? Anyone know?
Jul 04, 2007 08:19 PM|kbeeveer46|LINK
In the address bar where you would type www.google.com etc etc type in about:config and in the filter bar type in the network.dns stuff. It should filter out everything except that one thing. Double click it to change it to true
Jul 05, 2007 01:02 AM|blumonde|LINK
Thank you kbeeveer46.
Apr 02, 2008 12:33 PM|randomaccess|LINK
Thank you! This was causing me so much trouble... I thought the dev server was rebuilding the site with every request, or something like that. Never suspected ipv6!
Apr 29, 2009 06:22 PM|IvesMozart|LINK
Thanks for that. I would never guess that was the problem.
Jun 14, 2009 07:29 PM|Allixria|LINK
Well, I did it on my side, and yes I noticed an improvement.
Without disabling the IPv6 thing, I could run it on "custom server" option, at 1 sec time loading, and 10 sec via development server.
After disabling it, instead of a 10 sec loading in dev server, now I get a 3-4 sec loading. Still 1 sec via "custom server" option!!
So yes, it improves, but as far as I see, not enough to compare to the speed if you use the "Custom Server" option in your VS application properties.
Dec 01, 2009 07:25 PM|wdanda|LINK
Of all the suggestions to fix this problem, this is the only thing that worked for me... Uncomment the localhost address in the hosts file (%WINDIR%\System32\drivers\etc\hosts):
# localhost name resolution is handled within DNS itself.
I have blogged about this and other approaches here: http://www.wagnerdanda.me/2009/12/asp-net-development-server-slow-on-windows-vista7-with-firefox-or-chrome/
Now things are back to normal... And with my lightning fast
OCZ SSD it's a beauty to code :)
Feb 25, 2010 08:58 AM|gummikalli|LINK
This worked for me.
I am so gratefull for this post that I had to sign in just to say thank you :)
Feb 26, 2010 10:29 AM|blumonde|LINK
I used notepad to edit it the 'hosts" file but my web app. is still slow during testing via localhost. I have VS2008, IE8 and Wins 7. It takes at least 30 seconds to load a web-page everytime. It is really annoying. Everything is running locally. What is
it that causes it to load so slow?
Feb 26, 2010 10:50 AM|gummikalli|LINK
It was the about:config trick that worked for me, just type about:config in the firefox address bar. If you do however need to edit the host file you can open it from notepad. Make sure you run notepad as an administrator otherwise you will not be able to
Jul 07, 2010 09:26 AM|formationusa|LINK
The uncommenting of the localhost 127.0.0.1 line worked like a charm for me. Local executing is super fast.
asp.net development server
Nov 04, 2010 11:35 AM|schadeux|LINK
Thanks ghotiman! This solved my problem.