MozillaZine

Problems with DNS resolution -- DEFINITELY FIREFOX ONLY

User Help for Mozilla Firefox
goltz20707
 
Posts: 3
Joined: August 24th, 2007, 8:43 am

Post Posted August 24th, 2007, 9:33 am

I haven't been able to find useful help for this anywhere else. I'm running Firefox 2.0.0.6 on Windows XP (version 5.1, SP2). Quite frequently DNS lookups in Firefox come to a complete halt. The browser will sit for a minute or more saying "Looking up www.computerworld.com... or some such.

Before anyone jumps in with an answer, let me tell you what I know it is NOT.

It's not a network issue. DNS works just fine. I ran a live packet capture at the same time as I was browsing, and the DNS requests go out and come back in very short order. In the above lookup of www.computerworld.com, the system sent out a request and got back an answer in 0.256 seconds. Firefox kept waiting and waiting. I was able to open up IE, mistype the address, correctly type it, and have IE load and render the page, and then type the first paragraph of this post before Firefox resolved www.computerworld.com.

It's not a system issue. See above. No other application is having the slightest problem resolving names.

It's not an IPv6 issue. I have network.dns.disableIPv6 set to true, and I am not seeing any IPv6 DNS queries (type AAAA) going out.

I don't think it's an add-on/extension issue. I've seen this behavior even with all extensions disabled. I haven't tried starting Firefox in safe mode and running it until something happens, because I haven't had time.

I've done a number of searches on the subject and it looks like lots of people are having the same problem, on different platforms, with and without various extensions. Many people assume it's an issue with DNS and not with Firefox. Others think it's related to IPv6 lookups.

Has anyone else experienced this and managed to fix it? I'm almost ready to abandon Firefox out of necessity and switch back to IE. (The conspiracy theorist in me thinks Microsoft released a "patch" to cause this problem, for just this reason.)

trolly
Moderator

User avatar
 
Posts: 39908
Joined: August 22nd, 2005, 7:25 am

Post Posted August 24th, 2007, 9:47 am

Can you try to disable the internal DNS cache?
http://kb.mozillazine.org/Network.dnsCacheEntries

If it does not happen with the internal cache disabled and you can prove that the DNS answers (A records) arrive in time then we have finally the cause of this problem. It is a long standing problem.

Can you do this with a plain new profile?

There are no known fixes which works for all people. Some get it fixed with a faster DNS server, others claim that disabling the internal DNS cache solves it.
Think for yourself. Otherwise you have to believe what other people tell you.
A society based on individualism is an oxymoron. || Freedom is at first the freedom to starve.
Constitution says: One man, one vote. Supreme court says: One dollar, one vote.

VanillaMozilla
 
Posts: 13808
Joined: November 7th, 2005, 11:26 am

Post Posted August 24th, 2007, 10:18 am

Well, there are a lot of possibilities, and it's hard without seeing your computer. I do know that sometimes things are not as they seem.

For a start, I don't know why you are attributing this to domain-name resolution when you say domain-name resolution is working fine. Firefox did load that page, which tells you right away that the Windows domain-name resolver did not time out (although it could have been slow).

There are a bunch of other possibilities. For example, you could be blocking something. Perhaps you have some flaky security software. Or perhaps you are blocking ads. <i>You could be forcing Firefox through a proxy.</i> Hey! Or perhaps Fx had part of the computerworld.com page but was waiting for some ads or other part of the page. You can't even be sure it's getting served the same Web page as IE.

I wouldn't even consider this a test unless you run in safe mode for a while and consistently observe the same problem. If that doesn't work, you need a new, default Firefox profile, to make sure it isn't some wacko setting.

DNS servers can be erratic. Sometimes they work great; other times hardly at all, if you have a bad one. And they always cache results, so the second lookup attempt is fast. If you have any doubt about whether domain-name resolution is working correctly, get program "wdnslookup" and use it to look up a bunch of Web sites you've never been to. Pick some really uncommon ones that are unlikely to be cached by domain-name servers (you can get them from page 10 of an oddball Google search). Usually find 4 to 6 seconds.

goltz20707
 
Posts: 3
Joined: August 24th, 2007, 8:43 am

Post Posted August 24th, 2007, 10:39 am

Update: I've created a new profile for testing purposes, and will be using that until the problem recurs. I am refraining from using any extensions or other add-ons.

VanillaMozilla: I misspoke. A more accurate description of the problem is that Firefox seems to be having problems with domain name lookups. No other application on this system is having any problems, and the DNS infrastructure appears to be functioning normally. That is why I believe it is a Firefox problem and not related to anything on the system or network level. I'm very familiar with DNS from the protocol level on up -- trust me, it's not a DNS issue.

This happens with numerous different web pages -- Computerworld was just one example. In fact, it happens even with local sites within our network. There is a web proxy, but it's at the gateway between us and the outside world, so that wouldn't affect internal lookups or page loads.

trolly: Did you mean network.dnsCacheEntries or network.dns.CacheEntries (note the extra dot after "dns")? I assume it's an integer value. Should I set it to zero to disable caching? (It's currently not in the config in this new profile, and network.dns.disableIPv6 is "false".)

VanillaMozilla
 
Posts: 13808
Joined: November 7th, 2005, 11:26 am

Post Posted August 24th, 2007, 11:16 am

If you have a different proxy set up with Firefox than with IE, that could certainly make a difference.

I'm not sure if you should change more than one thing at a time. For example, if you create a new profile and then change the network setup, you won't know which was the cause of the problem. I think you first should check whether you are certain that you have the problem with a new profile and absolutely default settings (with the possible exception of disabling Java if you want).

trolly
Moderator

User avatar
 
Posts: 39908
Joined: August 22nd, 2005, 7:25 am

Post Posted August 24th, 2007, 12:10 pm

According to the docs it is network.dnsCacheEntries.
If the dns answer (A record) definitely arrives and firefox still tells "server not found" then something is wrong within firefox. In another thread a person can load the page in IE while firefox is reporting "server not found" at the same time.
It looks like the lookup is done asynchronously. If the answer gets lost somehow ...
Think for yourself. Otherwise you have to believe what other people tell you.
A society based on individualism is an oxymoron. || Freedom is at first the freedom to starve.
Constitution says: One man, one vote. Supreme court says: One dollar, one vote.

goltz20707
 
Posts: 3
Joined: August 24th, 2007, 8:43 am

Post Posted August 31st, 2007, 8:28 am

Update: I've been running for a week with a new, no-frills profile, with no problems. So it looks like the problem lies in one of the (admittedly many) extensions and add-ons I have loaded. I'll try loading each of the add-ons one at a time and running for a while, and we'll see when the problem pops up again.

VanillaMozilla
 
Posts: 13808
Joined: November 7th, 2005, 11:26 am

Post Posted August 31st, 2007, 9:14 am

I know I suggested it, but in retrospect it's hard to imagine how that could affect it, unless maybe you have some wacko extension that deals with networking?? Sometimes it's not easy diagnosing an intermittent problem, but please keep at it. Trolly and I have suspected that there may be a problem, but we're not sure, and it's very difficult to diagnose without being able to observe it. You're the first that I know of to come up with hard evidence.

I suppose you could try adding maybe half of the extensions at a time to speed up the process. I assume you have found that the Profile Manager can help with this process. Another possibility: a change in network settings in about:config? Maybe you've already covered that -- I forget.

Oh, yes. Did you try Trolly's suggestion? He's really curious to determine whether disabling the internal domain-name cache has an effect. That might be more important than testing extensions. I think you and he could be on to something.

EvilSteve
Guest
 

Post Posted October 27th, 2007, 6:25 am

I've been having exactly the same problem lately. I've tried all of the above solutions, and none of them make a difference.
I've noticed it seems to happen after a certain number of queries. Looking up some site with loads of items in it, like someones MySpace page causes the "Looking up blah..." bug to show up almost immediately.

I have no extensions or add ons except for the bug reporting one, Talkback, and I'm running Windows XP Professional 64-bit.
I've tried reinstalling firefox and deleting and re-creating my profile, no difference.

Anyone got any more ideas?

Cheers,
Steve

trolly
Moderator

User avatar
 
Posts: 39908
Joined: August 22nd, 2005, 7:25 am

Post Posted October 27th, 2007, 6:33 am

What about using a different DNS server?
http://www.opendns.com/ is a possible alternative.

I have never seens any problems with DNS. Maybe my ISP is running very fast and reliable DNS servers.
Think for yourself. Otherwise you have to believe what other people tell you.
A society based on individualism is an oxymoron. || Freedom is at first the freedom to starve.
Constitution says: One man, one vote. Supreme court says: One dollar, one vote.

kbalaji12
 
Posts: 8
Joined: September 25th, 2008, 5:18 am

Post Posted September 26th, 2008, 4:22 am

Hi!

I am using firefox 2.0. When I tried to set this entry to 0 it was still caching the entry and opening the old page as suggested opened with IE and it worked. Is there any other better way to disable dnsservice ?

Thanks
Balaji Kamal Kannadassan

VanillaMozilla
 
Posts: 13808
Joined: November 7th, 2005, 11:26 am

Post Posted September 26th, 2008, 5:57 am

kbalaji12 wrote:it was still ...opening the old page

If it was opening the page, I don't think Firefox has any DNS problem.

This thread is quite old. You probably need to start a new thread and describe the problem in detail.

EDIT: I see you did, here: viewtopic.php?f=38&t=871775 . Someone should close this old thread.

trolly
Moderator

User avatar
 
Posts: 39908
Joined: August 22nd, 2005, 7:25 am

Post Posted September 26th, 2008, 6:16 am

As you wish. Locking.
Think for yourself. Otherwise you have to believe what other people tell you.
A society based on individualism is an oxymoron. || Freedom is at first the freedom to starve.
Constitution says: One man, one vote. Supreme court says: One dollar, one vote.

Return to Firefox Support


Who is online

Users browsing this forum: Bing [Bot] and 4 guests