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Browsers are often configured to automatically detect settings as a convenience for networks that use proxy servers. Most of us don't need this.

I'm on Firefox 3.6 in Windows XP Home Edition service pack 3. I experience a lot of "server not found" when opening Firefox. Should i have proxy settings checked - "no proxy" or "auto-detect proxy settings for this network". I really don't know about proxy.

This is actually a very simple answer: unless you know you're using a proxy, select no proxy.

Even better, for IE and Firefox users alike, "auto detect", while intended to make life easier is - fundamentally evil.

Not for any malicious reasons, it just gets in the way. I'll explain why.

The issue here is very simple, when "auto detect" is turned on, your browser takes time on every start-up to figure out what the settings should be.

For 99% of you that's time totally wasted.

Most of the time, there is no proxy, and spending time every time you start your browser looking for one is just silly.

In Internet Explorer the setting is in Tools, Internet Options, Connections, LAN Settings:

IE Connections Dialog

Make sure that "Automatically Detect Settings" is unchecked. In many versions of IE it is checked by default and slowing you down.

In FireFox go to Tools, Options..., Advanced, Network, Settings...:

FireFox Connections Dialog

Make sure that "No proxy" is selected.


If you know you're behind or using a proxy server, then don't do what I just suggested, it'll probably break your connectivity.

If you suspect you're behind or using a proxy server, then look at the settings and perhaps even jot them down before you do anything. If it shows you're connecting through a proxy server, then don't do what I just suggested because it will probably break your connectivity.

If things break after doing this, then return the settings to their previous values.

But for the vast majority of you, particularly at home, this little tweak may speed up your browser's load time noticeably.

Article C4256 - April 3, 2010 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?


Houssam Mousa
April 3, 2010 2:36 PM

But This feature is important when connecting from various location, and many times, when behind Routers, specially for detecting DNS Servers, am I right ?, This feature is not important if you connect from single source, but for a portable Laptop, I think it's important to detect various Sourcer

This feature has nothing to do with DNS. DNS is a general networking attribute, and proxys and auto-detect in this discussion apply only to your browser.

Bernard Cawley
April 6, 2010 8:33 AM

Related to this: we just got a piece of spyware (ironically called AntiVirus) from a video streaming site on Sunday and one of the things it did was configure a proxy server in IE (it didn't do this in Firefox, which is the default and most used browser on that machine). So if you go into your proxy settings and see one configured when you normally wouldn't be using one (say, at work and on a big corporate intranet) DON'T just assume it's *supposed* to be there.

Wendyl Leslie
April 6, 2010 8:52 AM

Awesome! It's amazing all the neat "stuff" I've learned from you, Leo! You've made my computing experience much more enjoyable, efficient, and stress-free. Thanks for all you do!

Glenn P.
April 6, 2010 6:39 PM

Phoo!!! [edited] No wonder people detest Microsoft!!!

There is no WAY that "Auto-Detect" should EVER work this way! An "Auto-Detect" option, once checkmarked, should be intelligent enough to:

          1. Search out whatever relevant settings the program needs, JUST ONCE;
          2. Record  those settings for the program's future reference; and then
          3. Automagically "uncheckmark" itself!

In that way, the program WOULDN'T be slowed down, yet the "Auto-Detect" option would still be available for the user if his or her future needs should ever change. This should be applicable to ANY  program with any "Auto-Detect" feature (or equivalent), not just a browser!

avid E.
April 8, 2010 2:02 AM

I have been using computers since before Windows 3.11, and now use XP, SP3, IE7, and never have been made aware of this little tib bit about speeding up my startup by deselecting the auto- detect. Thanks very much.

September 10, 2010 9:36 PM

omg you saved me my browser on windows 7 which is IE8 was slow i unchecked this and now its fast again thanks.

March 3, 2012 4:37 PM

Thanks for such a plain English explanation! I was on the Microsoft 'Support' site for over a half an hour trying to figure out the answer to this.

Even though I'm not a programmer or an IT expert, I'm definitely Not computer illiterate and can usually figure out things as long as I have a user guide or can find a decent help article. But sometimes it seems like Microsoft takes extra time to make their 'help' pages unintelligible and make people feel like idiots (perhaps so we won't mess around with settings that MS thinks we should keep?).

Anyway, thanks so much. You were able to explain this in 1 page, and it took me all of 5 minutes to read, understand, and adjust my settings. Well, maybe 10 minutes, if you include the time for me to write this comment - but it was well worth it!.

Thanks for Not making me feel like a complete idiot! I'll be sure to come back to your site in the future, especially if (when) the MS pages start trying to make me feel stupid. :-)

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