Firefox just quit working. Why?

[joe at actionline.com]

.
Craig White's suggested remedy (quoted below) did fix the problem, but it
is still a mystery what triggered this failure.  I did look at the proxy
settings and they were/are identical on the two systems.

I'd still very much like to know what could possibly have triggered this
abrupt failure when the system had been working fine and no changes were
made.  Firefox just quit working right in the middle of a session. Very,
very strange.  And the other identical system is still working fine
without implementing the remedy that Craig suggested.

Any ideas out there?



> Look for proxy settings inside firefox?
>
> On Sat, Feb 20, 2010 at 9:39 PM, Craig White <craigwhite at azapple.com>
> wrote:
>> On Sat, 2010-02-20 at 21:08 -0700, Technomage wrote:
>>> On 2/20/10 9:00 PM, Josef Lowder wrote:
>>> > I have Firefox 3.5.6 running on two identical Thinkpad computers.
>>> >
>>> > It has been working fine on both for several months, but today, it
>>> > just quit working on one of them with the message quoted below. Both
>>> > are wirelessly connected on the same network. No changes were made on
>>> > either one. I have rechecked that all the settings are identical on
>>> > both computers.  The one on which Firefox just quit working works
>>> fine
>>> > with Konqueror.  I have checked and rechecked everything I can think
>>> > to check.  I tried reinstalling Firefox from Synaptic.  What could
>>> > have caused Firefox to just quit working?  What can I do to get it
>>> > working again?
>>> >
>>> > Server not found
>>> > Firefox can't find the server at www.google.com.
>>> > * Check the address for typing errors such as
>>> >    ww.example.com instead of www.example.com
>>> > * If you are unable to load any pages, check your computer's network
>>> connection.
>>> > * If your computer or network is protected by a firewall or proxy,
>>> > make sure that Firefox is permitted to access the Web.
>>
>>> >
>>> Its not a firefox issue. its a dns issue. How identical are the
>>> machines
>>> in question?
>>> running all the same processes? can you ssh from/to them?
>>>
>>> I see a lot of such errors, not just with mozilla firefox, but also
>>> with
>>> safari, IE and even opera.
>>> Generally, it turns out to be a dns lookup failure.
>> ----
>> that's not all that helpful because he clearly stated that Konqueror
>> browses the web fine on the same computer where Firefox does not.
>>
>> Seems pretty clear from the evidence above that Firefox that isn't
>> working is trying to use IPV6 DNS which is failing whereas Konqueror
>> does not.
>>
>> - Open Firefox...
>>
>> - type 'about:config' in the address bar and lie to Firefox and tell it
>> you'll be careful
>>
>> - type 'ipv6' in the 'filter box and you will see a setting for...
>>
>>  network.dns.disableIPv6
>>
>>  which is undoubtedly set to 'false. Double click it to change it to
>> true.
>>
>> I would bet that this fixes the problem which would mean that the
>> Firefox that works only has IPV4 running and the one that doesn't has
>> both IPV4 and IPV6 running but you cannot resolve DNS via ipv6.
>>
>> Craig