Thanks so much for discovering and posting this work-around!

Could you please be more explicit about exactly what settings should be applied, how to get to the screens where those settings should be made, and when to make them (before or after updating; can they be applied after the update, once the problem has already surfaced)? I know that those detailed directions would be a big help to me, and probably to a lot of others as well.

Thanks again!

Solution works fine even after installing FF36 and I have had no problems at all today for the first time since I installed it.

Use the following either of the following links to see how to manually set DNS:

http://support.simpledns.com/kb/a72/configuring-windows-7-to-use-local-dns-server.aspx

https://developers.google.com/speed/public-dns/docs/using

Thanks for the link!

It sounds like this issue is due to a bug of some sort in the V36 update, no? If you or anyone else has any familiarity or past experience with how Mozilla works, would you expect that this is a 'glitch' whose correction will make it to an update of Firefox relatively quickly, or do you imagine that it will take some time before this is smoothed out?

Hi smow, Thanks for posting a workaround.

People are already posting links to this thread. Perhaps you would like to give more information about the problem you see, maybe someone can provide a solution.

• Note you aught to be able to attach screenshots in this thread
  How do I create a screenshot of my problem? (\use something compressed: a .jpeg or .gif rather than a bitmap, Windows snipping tool would be create a suitable image file.)

However I am sure a lot of users will want to know what causes any such problem, and of course if the problem may be demonstrated and confirmed I am sure Firefox developers will be interested in this and we (this forum & site) will try to document or better still get a fix for the problem)

Anyone with this problem

Please vote by using the button [I have this problem, too] If you do see a problem and need a solution please post a new question of your own. When doing so please try to follow the prompts to include full troubleshooting information, using the add-on offered. Please use this special link to post.

I was using v36 with no problems. I added a password to my winXP user account and the system hung during application of security creds to all my files. Upon restarting, FFv36 continually give SERVER NOT FOUND error to any URL, while Chrome responds fine. It seems to me that something is blocking before even trying to resolve DNS. It works great in SAFE MODE w/ NETWORKING. So something my system is loading is blocking -- cannot determine what!! If anyone has any steps to try -- please reach out!!

Hi AG, I see you already have your own thread:

• Server Not Found error only affects Firefox /questions/1049876

Ag - your problem does seem different as you had FF36 working.

Whereas the problem a lot of us have is that when we upgrade from FF35 to FF36 we get a lot of Server not found errors when trying to load webpages.

Sometimes they load and then they stop loading, and then if you hit refresh a lot they sometimes then load again, or you have to wait a minute or two and then they load.

For some reason using an external DNS server {see #answer-698286 _~J99} has stopped this problem completely, as does going back to FF35.

We would need an expert on DNS resolution at Mozilla to look into this. [*]^{See My note under ~J99} Strikes me that using an external DNS server adds some latency to the name resolution and maybe this is needed for the network card in the PC's that are having this problem to resolve the webpage addresses.

Obviously something has changed from FF35 to FF36 to cause this problem. I am open to Mozilla contacting me via Email if they wish me to try anything else to help them pin this down.

*

edit Note from John99 Mozilla may investigate IF we are able to provide evidence supporting this. We need to be able to file a bug with good Steps To Reproduce (STR). Developers need to be able to see the problem themselves before we can expect them to look into this.

Hey, smow. That was very good work. Well Done. Please flag your last post #answer-698286 as Solved Problem so other will know.

If the problem is real and related to F36 we need to file a bug to get this investigated and fixed. (The 503 errors I did get turned out to be genuine server glitches.)

I am not able to reproduce personally, and am not going to file a bug for this unless I see multiple posts confirming the problem. In fact if this problem goes away in Windows safemode it could be some Windows issue or due to third party software or even malware. I did invite others to vote and post, but I am not seeing votes increasing, or any additional posts check

The problem may be real but site or ISP specific. That would explain why we are not seeing many reports of this, and why (afaik) no bug has been filed. As I mentioned upthread attaching a screenshot and giving examples where this is seen may help.

1. To rule out malware please scan with multiple tools as explained in
   • Troubleshoot Firefox issues caused by malware
   • For general problem with page loading see
     Firefox can't load websites but other browsers can
     Websites show a spinning wheel and never finish loading
2. If you do suspect the issue due to a Firefox 36 problem. One change in Fx36 was support for HTTP/2 and conceivably that could somehow be involved. It is possible to temporarily disable that for test purposes. (Remember to flip the pref back again after testing)
   Toggle the two prefs to false using about:config
   1. network.http.spdy.enabled.http2
   2. network.http.spdy.enabled.http2draft
   • See http://kb.mozillazine.org/About:config

_{edit: couple of typos}

Looks like there was a major DNS change to FF 36 and it has a bug fix already allocated to it.

https://bugzilla.mozilla.org/show_bug.cgi?id=1093983

A quick test appears to verify this was the problem. I reverted back to using my local ISP's DNS server and then went into about:config and set network.dns.get-ttl to false. You then have to exit out of FF and run it again. After that it all works without problems as far as I can see.

So the next build may well have this fixed but for now the change to get_ttl fixes things.

Any chance someone with access to the bug system can update the bug report to point to the problems some of us have been having due to the change and how we now have to disable get-ttl to get server names resolved. Thanks.

Well done. Thanks for finding that.

That is not only assigned but has an approved patch included in the scheduled Fx36.0.1 release so it should be fixed in few days, watch out for the upgrade.

• Bug 1093983 - DNS resolver should not use 'ANY' to get cached records for TTL ^c#35
• https://wiki.mozilla.org/Firefox/Channels/Meetings/2015-03-03#Schedule_Update

With the bug now fixed it would not really be appropriate to add further comment. I do now see another related bug assigned but not being fast tracked, so if all goes well that will probably land in Firefox 39.

• Bug 1138242 - DNS: Request A and AAAA record types rather than ANY when obtaining TTL on Windows

Thanks for the pointer to how to resolve, I will post locally, as it's been causing severe pain here in Ireland with local ISP's, with many transactions hanging or failing to complete on the first attempt.

Irish_Steve A change being made any day now and released as Fx36.0.1 may resolve this issue. If you use Firefox Menu Button -> Help -> AboutFirefox each day that will check to see if the upgrade is available.

There is a pref change that may be implemented by a use of about:config, but it is probably best not to advise the average end user of Firefox to try to do that.

For those wishing to try the fix immediately /questions/1049876#answer-699245

The easiest method is just to wait a few days for the Fx36.0.1 update. If you use
Firefox Menu Button -> Help -> AboutFirefox
each day that will check to see if the upgrade is available.

The bug fix is I think merely changing prefs and so you could do that yourself. It may be safer to use a spare additional profile, or backup the file prefs.js when trying that initially, because making mistakes in about:config may break Firefox.

• http://kb.mozillazine.org/Prefs.js_file
• http://kb.mozillazine.org/About:config
• Profile Manager - Create, remove or switch Firefox profiles

Just toggling the pref network.dns.get-ttl to false should fix the issue, that basically is what is done in

Bug 1093983 - DNS resolver should not use 'ANY' to get cached records for TTL 

One of the bug fixes about to be applied in the imminent Fx36.0.1 point Release

Note Firefox 36.0.1 is now out. That may resolve some of these issues.

smow

Does 36.0.1 work ok for you now with pref network.dns.get-ttl toggled to default. (Default should now be false)

36.0.1 does seem to have fixed the problem - which isn't a surprise as it simply did what we had already done manually - setting network.dns.get-ttl to false.

Nice to have it fixed in the build though and not have to run about:config to sort it out.

setting network.dns.get-ttl to false DID NOT correct the issue on my machine. Are there others experiencing the same on WinXPsp2?

I'm running XP Home SP3 here, and having upgraded to 36.0.1 and reset the TTL setting to false, I'm still seeing issues with slow or non responsive pages with Firefox, and I'm not having the same issues with Chrome, so it would seem that maybe something else is also implicated in this situation.

What I have noticed is that I can almost guarantee that if I do an obsure Google search, it won't return the first time of asking, and a web site that I've not been to since clearing the cache is also likely to fail, but a regular use site is less inclined to be a problem.

One thought, based on a somewhat suspect memory from a long time ago, there was a suggested fix for another issue that meant changing the size of the DNS cache in firefox, what is the default setting for that value, in case the cache here is either too large, or maybe now too small because of the way that the DNS is being used with the recent changes.

You may have similar symptoms, but different causes of the problem. I suggest you continue with your own existing questions.

AG

• Server Not Found error only affects Firefox /questions/1049876

Irish_Steve

• Firefox 36 DNS issues, revert to 35 or go to beta to get patch? /questions/1050071

You had already marked that as solved by Fx 36.0.1 /questions/1050071#answer-698850. I will remove the solved marking for you, and I suggest you post there again to confirm Fx36.0.1 does not help you.