Hi Folks,
My Mozilla browser has suddenly, for no apparent reason, stopped doing DNS lookups. I was using Mozilla quite happily doing some web browsing yesterday evening then temporarily exited it to check my emails using Kmail. I then restarted Mozilla and, frustratingly, discovered that I could no longer browse the web with it. Every time I type in a URL it immediately comes back saying page not found. If however I do a ping to suss out the websites IP Address and type this IP Address directly into Mozilla then it finds the webpage and loads it ok.
The problem still exists this morning, even though I have rebooted my PC several times in the mean time. I can of course still check my emails and ping using URLs, I can even use the Opera browser without problems; it is just the DNS lookup part of Mozilla which has stopped working.
Has anyone else come across this problem? If so how did you solve it?
Confused and bewildered...
Ian.
Ian Douglas alug@the-zub.demon.co.uk wrote:
Has anyone else come across this problem? If so how did you solve it?
Not seen that. Try looking through the preferences, especially the Advanced/Proxy ones. No idea why it would suddenly happen, though.
On Thu, Feb 06, 2003 at 11:13:42AM +0000, MJ Ray wrote:
Ian Douglas alug@the-zub.demon.co.uk wrote:
Has anyone else come across this problem? If so how did you solve it?
Not seen that. Try looking through the preferences, especially the Advanced/Proxy ones. No idea why it would suddenly happen, though.
Is is just Moz that displays the problem? or other programs affected in anyway? could it be duff settings in resolv.conf? (yes, I missed the origional message ;)
Brett
On Thursday, February 06, 2003 11:22 AM, Brett Parker wrote:
Is is just Moz that displays the problem? or other programs affected in anyway? could it be duff settings in resolv.conf? (yes, I missed the origional message ;)
Hi Brett,
No, as far as I can tell it is only Mozilla which has got confused. I can, for example, do a simple ping using a URL:
ian@suzy:~> ping www.alug.org.uk PING www.alug.org.uk (199.254.168.73) from 192.168.1.131 : 56(84) bytes of data. 64 bytes from carpediem-it.co.uk (199.254.168.73): icmp_seq=1 ttl=237 time=215.909 msec 64 bytes from carpediem-it.co.uk (199.254.168.73): icmp_seq=2 ttl=237 time=265.918 msec 64 bytes from carpediem-it.co.uk (199.254.168.73): icmp_seq=3 ttl=237 time=200.619 msec --- www.alug.org.uk ping statistics --- 3 packets transmitted, 3 received, 0% loss, time 2018ms rtt min/avg/max/mdev = 200.619/227.482/265.918/27.885 ms
I can also still send and receive email, and even use the Opera browser ok. It only appears to be Mozilla that is broken.
My very simple resolv.conf just says:
ian@suzy:~> cat /etc./resolv.conf search noahsark.the-zub.net nameserver 194.168.4.100 nameserver 194.168.8.100
Which is what it normally says.
Ian.
On Thursday, February 06, 2003 11:13 AM, MJ Ray wrote:
Not seen that. Try looking through the preferences, especially the Advanced/Proxy ones. No idea why it would suddenly happen, though.
Hi Mark,
Thanks for your suggestion. Yes, it is confusing me too as I have not touched the Mozilla preferences since I originally set it up ages ago, and certainly not during the three minute gap while I checked my emails last night, though that does not mean of course that there may be a fundamental mistake in my settings which has only now come to light!
Looking in Edit > Preferences > Advanced > Proxies I have a dot in the circle: "Direct connection to the internet". This makes all the boxes in the "Manual proxy configuration" section beneath it, and the "Automatic Proxy Configuration URL" below that, empty and greyed out.
I access the internet though an NTL broadband connection. Do you think I should perhaps disable the "Direct connection" option and insert some URLs into the "HTTP Proxy" and associated "Port" boxes under the "Manual Proxy Configuration" section???
Ian.
Ian Douglas wrote:
[SNIP]
I access the internet though an NTL broadband connection. Do you think I should perhaps disable the "Direct connection" option and insert some URLs into the "HTTP Proxy" and associated "Port" boxes under the "Manual Proxy Configuration" section???
NTL run transparent caches and proxies, and they are known to break. Try using another proxy, which will cause you to bypass the transparent NTL ones, and see what happens. This doc:
http://homepage.ntlworld.com/robin.d.h.walker/cmtips/trancache.html
...explains all.
Cheers, Laurie.
Laurie Brown laurie@brownowl.com writes:
Ian Douglas wrote:
I access the internet though an NTL broadband connection. Do you think I should perhaps disable the "Direct connection" option and insert some URLs into the "HTTP Proxy" and associated "Port" boxes under the "Manual Proxy Configuration" section???
NTL run transparent caches and proxies, and they are known to break.
AFAIK they don't intercept DNS, however. (I'm not sure what the point would be anyway, it's not exactly a high-bandwidth protocol.)
Richard Kettlewell wrote:
Laurie Brown laurie@brownowl.com writes:
Ian Douglas wrote:
I access the internet though an NTL broadband connection. Do you think I should perhaps disable the "Direct connection" option and insert some URLs into the "HTTP Proxy" and associated "Port" boxes under the "Manual Proxy Configuration" section???
NTL run transparent caches and proxies, and they are known to break.
AFAIK they don't intercept DNS, however. (I'm not sure what the point would be anyway, it's not exactly a high-bandwidth protocol.)
When you're stuck, anything is worth a go!
On Thursday, February 06, 2003 12:27 PM, Laurie Brown wrote:
NTL run transparent caches and proxies, and they are known to break. Try using another proxy, which will cause you to bypass the transparent NTL ones, and see what happens. This doc:
http://homepage.ntlworld.com/robin.d.h.walker/cmtips/trancache.html
...explains all.
Hi Laurie,
Thanks for your suggestion. I went to the webpage you suggested and tried the http://www.broadband-help.com/cm_diagnose.asp?init=1 link. It said:
Proxy IP 213.107.224.5 [WHOIS] Proxy Name(Raw) HTTP/1.1 ntl-site[D56BE005] (Traffic-Server/5.1.3-50227-50963-51463 [uSc ]) Proxy Name(R-DNS) cache2-colc.server.ntli.net
When I tried the http://www.all-nettools.com/pr.htm link it said: You came via: HTTP:/1.1 ntl-site[D56BE004] (Traffic-Server/5.1.3-50227-50963-5146 Remote Address: 213.107.224.4 Remote Host: 213.107.224.4
The "Remote Host IP Address" above is however different from the ISP assigned IP Address of my cable modem.
I think I need to stop and take some time to read through that http://homepage.ntlworld.com/robin.d.h.walker/cmtips/trancache.html webpage you suggested in order to suss out what the above information means, and how I should therefore adjust my Mozilla (or general Linux) settings. Unfortunately I have however just started getting an earful about spending too much time playing with my PC and why isn't lunch cooking yet, so must leave this for a while...
Ian.
"Ian Douglas" alug@the-zub.demon.co.uk writes:
MJ Ray wrote:
Not seen that. Try looking through the preferences, especially the Advanced/Proxy ones. No idea why it would suddenly happen, though.
Hi Mark,
Thanks for your suggestion. Yes, it is confusing me too as I have not touched the Mozilla preferences since I originally set it up ages ago, and certainly not during the three minute gap while I checked my emails last night, though that does not mean of course that there may be a fundamental mistake in my settings which has only now come to light!
Try quitting mozilla, moving your ~/.mozilla directory out of the way (e.g. 'mv .mozilla .mozilla.save') and starting mozilla.
If the problem persists then it's definitely nothing to do with your preferences. But if it goes away then it may be a function of your preferences - possibly something you set and forgot about, but also possibly something that has become corrupted (which might be caused by a Mozilla bug, an OS bug, a hardware fault, or who knows what).
To restore you old settings, quit mozilla, remove any newly created ~/.mozilla and move the old one back into place. (If you just try to move it back without removing the newly created one, you'll not get the effect you want.)
On Thursday, February 06, 2003 12:28 PM, Richard Kettlewell wrote:
Try quitting mozilla, moving your ~/.mozilla directory out of the way (e.g. 'mv .mozilla .mozilla.save') and starting mozilla.
If the problem persists then it's definitely nothing to do with your preferences. But if it goes away then it may be a function of your preferences - possibly something you set and forgot about, but also possibly something that has become corrupted (which might be caused by a Mozilla bug, an OS bug, a hardware fault, or who knows what).
Hi Richard,
I tried renaming my /homeian/.mozzilla directory as you suggested but when I then restarted Mozilla I noticed it asked me if I wanted to import my settings from Netscape (which still works) so I said yes. The new Mozilla still however fails with:
"Alert: www.alug.org.uk could not be found. Please check the name and try again"
But if I use ping to discover the IP Address of www.alug.org.uk and then type it (http://199.254.168.73) into the browser the PHP4Hosting.com homepage appears rather than the ALUG webpage I was expecting. This confuses me, but is probably simply an unrelated point.
If I rename the ~/.mozilla directory a second time and restart Mozilla, but this time create a new user profile, rather than importing my Netscape one, the problem still exists.
Ian.
"Ian Douglas" alug@the-zub.demon.co.uk writes:
But if I use ping to discover the IP Address of www.alug.org.uk and then type it (http://199.254.168.73) into the browser the PHP4Hosting.com homepage appears rather than the ALUG webpage I was expecting. This confuses me, but is probably simply an unrelated point.
Yes, it is unrelated, and will occur even when DNS is working fine.
If I rename the ~/.mozilla directory a second time and restart Mozilla, but this time create a new user profile, rather than importing my Netscape one, the problem still exists.
I think the next step is to determine if Mozilla is even sending any DNS queries. As root, this command:
tcpdump -n port 53
will report any DNS packets appearing on your ethernet.
Do a ping with this running first; you'll see the kind of thing that ought to be happening (there ought to be a request and a response).
Then try to visit a website through Mozilla and see what you see. Paste it all into another message to this list if you have trouble interperting it.
That said if Mozilla has randomly decided to stop doing DNS lookups I'm not sure what you can do about it, other than possibly reinstalling Mozilla.
On Thursday, February 06, 2003 2:48 PM, Richard Kettlewell wrote:
I think the next step is to determine if Mozilla is even sending any DNS queries. As root, this command:
tcpdump -n port 53
will report any DNS packets appearing on your ethernet.
Do a ping with this running first; you'll see the kind of thing that ought to be happening (there ought to be a request and a response).
On console 1: ian@suzy:~> su - Password: suzy:~ # tcpdump -n port 53 tcpdump: listening on eth0 15:55:31.225452 192.168.1.131.1026 > 194.168.4.100.53: 22127+ A? www.alug.org.uk. (33) (DF) 15:55:31.247546 194.168.4.100.53 > 192.168.1.131.1026: 22127 1/3/0 A 199.254.168.73 (138) (DF) 15:55:31.568373 192.168.1.131.1026 > 194.168.4.100.53: 22128+ PTR? 73.168.254.199.in-addr.arpa. (45) (DF) 15:55:31.823014 194.168.4.100.53 > 192.168.1.131.1026: 22128 1/2/2 (156) (DF) 15:55:32.570950 192.168.1.131.1026 > 194.168.4.100.53: 22129+ PTR? 73.168.254.199.in-addr.arpa. (45) (DF) 15:55:32.589337 194.168.4.100.53 > 192.168.1.131.1026: 22129 1/2/2 (156) (DF) 6 packets received by filter 0 packets dropped by kernel
While on console 2: ian@suzy:~> ping www.alug.org.uk PING www.alug.org.uk (199.254.168.73) from 192.168.1.131 : 56(84) bytes of data. 64 bytes from carpediem-it.co.uk (199.254.168.73): icmp_seq=1 ttl=237 time=255.296 msec 64 bytes from carpediem-it.co.uk (199.254.168.73): icmp_seq=2 ttl=237 time=250.195 msec --- www.alug.org.uk ping statistics --- 2 packets transmitted, 2 received, 0% loss, time 1011ms rtt min/avg/max/mdev = 250.195/252.745/255.296/2.599 ms~>
Then try to visit a website through Mozilla and see what you see. Paste it all into another message to this list if you have trouble interperting it.
On console 1: suzy:~ # tcpdump -n port 53 tcpdump: listening on eth0 0 packets received by filter 0 packets dropped by kernel
While on console 2 I start Mozilla and type http://www.alug.org.uk and I get the "Alert: www.alug.org.uk could not be found. Please check the name and try again" error message.
That said if Mozilla has randomly decided to stop doing DNS lookups I'm not sure what you can do about it, other than possibly reinstalling Mozilla.
Hmmm... What I suspected. I thought it would be worth mentioning this problem on the list first though just in case anyone had come across the problem before and knew how to fix it.
Thanks for all your help,
Ian.
"Ian Douglas" alug@the-zub.demon.co.uk writes:
Hmmm... What I suspected. I thought it would be worth mentioning this problem on the list first though just in case anyone had come across the problem before and knew how to fix it.
A final thought that I should have mentioned before. If you're running Mozilla in an xterm (or whatever), you will see any error messages it writes to its standard output or standard error. This may be none whatsoever, but it might be worth checking anyway...
On Thursday, February 06, 2003 4:50 PM, Richard Kettlewell wrote:
A final thought that I should have mentioned before. If you're running Mozilla in an xterm (or whatever), you will see any error messages it writes to its standard output or standard error. This may be none whatsoever, but it might be worth checking anyway...
Hi Richard,
If I start Mozilla within an xterm I get:
ian@suzy:~> mozilla MOZILLA_FIVE_HOME=/opt/mozilla
LD_LIBRARY_PATH=/opt/mozilla:/opt/mozilla/plugins:/opt/mozilla//:/opt/mozill a//components:/opt/kde/lib:/opt/mozilla//:/opt/mozilla//components: LIBRARY_PATH=/opt/mozilla:/opt/mozilla/components SHLIB_PATH=/opt/mozilla:/opt/mozilla/ LIBPATH=/opt/mozilla:/opt/mozilla/ ADDON_PATH=/opt/mozilla:/opt/mozilla/ MOZ_PROGRAM=/opt/mozilla/mozilla-bin MOZ_TOOLKIT= moz_debug=0 moz_debugger=
Appear while Mozilla starts, then nothing else at all while using it.
Thanks again for your help,
Ian.
Ian Douglas wrote; ...[ snip ]...
Hmmm... What I suspected. I thought it would be worth mentioning this problem on the list first though just in case anyone had come across the problem before and knew how to fix it.
I did a quick search of current bug reports on the Mozilla bug list http://bugzilla.mozilla.org/query.cgi for the string 'DNS' and there were quite a few. Have you searched the Mozilla bug list yourself?
Keith ____________ Man always dies before he is fully born. - Erich Fromm
On Thursday, February 06, 2003 4:53 PM, Keith Watson wrote:
I did a quick search of current bug reports on the Mozilla bug list
http://bugzilla.mozilla.org/query.cgi for the string 'DNS' and
there were quite a few. Have you searched the Mozilla bug list yourself?
Hi Keith,
No I had not searched the bugzilla list as I did not know it existed. You are right, there do appear to be loads of DNS bugs reported. I guess it must be a particular weakness of the Mozilla software. The bug reports I looked at did however seem very specific. My case seems much more general (i.e. Mozilla suddenly stopped doing DNS lookups for ALL websites and the problem appears to be permanent and fatal totally unaffected by PC reboots or restarting Mozilla). I will have to look at the bugzilla bug list in more detail to see if I can get any ideas tomorrow, when I have more time, as I must finish with the PC now for tonight.
Thanks again for your help,
Ian.
I too have problems accessing certain web sites - www.ktmarketing.com is one, James Owen's elephant jpegs are another (lost the URL James..). In the past, I have had the same trouble with tesco.net (which uses the NTL backbone), yet found everything would connect when using freeserve. Now that I'm on NTL cable, I find parts of cyberspace to be out of reach.
Don't wast time calling the (alleged) Help desk - "We can see the pages, so it must be a configuration problem with Windows" is the typical reply. I'm waiting to see the senior network engineer after having a chat with one of the service techs. Some of the back room boys do acknowledge there is a problem !
Regards, Paul.
On Thursday 06 Feb 2003 6:55 pm, Ian Douglas wrote:
I guess it must be a particular weakness of the Mozilla software. The bug reports I looked at did however seem very specific. My case seems much more general (i.e. Mozilla suddenly stopped doing DNS lookups for ALL websites and the problem appears to be permanent and fatal totally unaffected by PC reboots
Ian Douglas alug@the-zub.demon.co.uk wrote:
But if I use ping to discover the IP Address of www.alug.org.uk and then type it (http://199.254.168.73) into the browser the PHP4Hosting.com homepage appears rather than the ALUG webpage I was expecting. This confuses me, but is probably simply an unrelated point.
The HTTP protocol includes the name of the host being asked for in the request, as a Host header. Apache's virtual hosting support uses that header to decide which web site to show, as it can have many hostnames, all pointing at the one IP address.
I'm not sure that we're any nearer understanding why only your browser is broken, though.
MJR
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Brett Parker -
Ian Douglas -
Keith Watson -
Laurie Brown -
MJ Ray -
Paul -
Richard Kettlewell