Unusual FF behaviour

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I just changed domain registrars for a couple of domains. one points to 
the other.  they were both working find 2 days ago.  I can access the 
primary (.net) no problem.  I cannot access the secondary (.com) 'Server 
not found'..  The hosting company (not the registrar) has the name 
servers (same for many years).  I can see the .com with my android 
phone, other people I know can see the .com with their computers. I have 
cleared the cache several times.  I have turned off cookies.  I have set 
cache to zero MB.  I have turned off the computer for a bit, then 
restarted.  I have run out of options. Oh yeah: ubuntu 16.04 and the 
latest firefox.

thoughts?
John


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    <font size="+1">I just changed domain registrars for a couple of
      domains. one points to the other.  they were both working find 2
      days ago.  I can access the primary (.net) no problem.  I cannot
      access the secondary (.com) 'Server not found'..  The hosting
      company (not the registrar) has the name servers (same for many
      years).  I can see the .com with my android phone, other people I
      know can see the .com with their computers. I have cleared the
      cache several times.  I have turned off cookies.  I have set cache
      to zero MB.  I have turned off the computer for a bit, then
      restarted.  I have run out of options. Oh yeah: ubuntu 16.04 and
      the latest firefox.<br>
      <br>
      thoughts?<br>
      John<br>
      <br>
    </font>
  </body>
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-1
John
12/31/2016 6:32:27 AM
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On Fri, 30 Dec 2016 22:32:27 -0800, John R. Sowden wrote:

> I just changed domain registrars for a couple of domains. one points to 
> the other.  they were both working find 2 days ago.  I can access the 
> primary (.net) no problem.  I cannot access the secondary (.com) 'Server 
> not found'..  The hosting company (not the registrar) has the name 
> servers (same for many years).  I can see the .com with my android 
> phone, other people I know can see the .com with their computers. I have 
> cleared the cache several times.  I have turned off cookies.  I have set 
> cache to zero MB.  I have turned off the computer for a bit, then 
> restarted.  I have run out of options. Oh yeah: ubuntu 16.04 and the 
> latest firefox.
> 
> thoughts?
> John


Try it with another browser on the same computer.  My Ubuntu 16.04 
comes with another web browser called "Ubuntu Web Browser" or just 
"Browser".

This page may help:
https://support.mozilla.org/en-US/kb/server-not-found-connection-problem


Check if your Ubuntu operating system can find the server's IP address.
Open a terminal window and enter the command
    nslookup -type=A  your-domain-name.com
Use the actual domain name in the command.



-- 
Kind regards
Ralph
🦊 
1
Ralph
12/31/2016 9:12:32 AM
"John R. Sowden" <jsowden@americansentry.net> wrote

......

  Try setting network.dnsCache* to 0 in about:config.
You should see 3 such entries. FF will otherwise cache
DNS data to avoid extra DNS calls. That saves a few
ms in webpage load time, but causes problems when
domain IPs change.
  If you use any special DNS software you can also
check that. For example, I use Acrylic for its HOSTS
file that accepts wildcards. That's a DNS go-between
that also has a cache.

  I think there's also DNS caching in Windows, which
can be cleared through obscure commandline incantations,
but I've never known Windows DNS caching to be a
problem. 


1
Mayayana
12/31/2016 2:15:29 PM
In article <mailman.987.1483193750.19729.support-
firefox@lists.mozilla.org>, mayayana@invalid.nospam says...
> I think there's also DNS caching in Windows, which
> can be cleared through obscure commandline incantations,
> but I've never known Windows DNS caching to be a
> problem. 
> 
> 

I've ran into that when the IP address of the target host  has changed. 
That is why one can flush the DNS buffers in Windows: from the CMD 
prompt,
ipconfig /flushdns
(I haven't had problems flushing the DNS buffers, but one might have to 
be logged in as administrator or might have to run CMD with 
administrator privileges. Rebooting seems to also clear the DNS cache, 
but takes far longer than an ipconfig /flushdns.)

Of course, if the DNS server that Windows (or your operating system) is 
configured to accesses still has outdated information (generally, where 
that DNS server has an A or AAAA record that hasn't exhausted it's time-
to-live timer, but the host had changed IP addresses before that had 
timed out), the A or AAAA record Windows then gets will still be wrong. 
(As far as I am aware, only OpenDNS allows us mere users to refresh its 
buffers by doing a "cache check" and then ask it to refresh, but even 
then OpenDNS would dig down only to the name server that directly points 
to the host. All other public DNS servers that I am aware of will 
normally hang on to a site's A or AAAA record until that record's time-
to-live field has expired, and only then will go after new A or AAAA 
records. As you can imagine, and as I had observed on rare occasion, it 
is then possible for different DNS servers to update at different times, 
and that is with DNS servers that respect the TTL field of the name 
record.)

Other operating systems also have their ways of flushing their DNS 
buffers.

Unfortunately, it is difficult to tell if the operating system has the 
right IP address in its DNS cache because pinging the host name will 
tell you whether an IP address is associated with that host name, but 
not if that IP address is current, and, alas, the next bit of what 
should be useful information is just that the address that one's 
operating system had returned is that the device at that address has the 
ping service enabled (or not/blocked), not whether or not that IP 
address is the correct one.

In addition, each browser may also have its own DNS cache. Generally, 
shutting down the browser completely (in Firefox, this means all Firefox 
windows) and relaunching it will empty its DNS cache, so then the names 
will be resolved by the browser asking the operating system for the name 
record.

The browser's DNS cache is separate from the browser's file cache, but 
it still a good idea to flush the browser's (file) cache, too, since if 
a host changes its IP address there may additional changes needed in the 
components of the web page (such as hard-coded IP addresses) that 
require refetches of all components of that web page.

As the above information implies, it can be a headache when a host 
changes its IP address, especially when the time-to-live DNS records 
have more than a few minutes in the TTL field.
1
Mark12547
12/31/2016 6:13:43 PM
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