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Intermittent connection issue

Hi all,

I have a really annoying intermittent problem with my internet conncetion, and I'm completely out of ideas, so I was hoping somebody here might be able to come up with something... it's complicated so bear with me while I explain it.

Basically, a few times a week for no apparent reason (or if I reboot my router), I will suddenly be unable to browse any websites or make any connections at all with other addresses on the internet e.g. ping, ssh, whatever. It affects all the computers in the house, not just one. This is despite the fact that my router has successfully synced, CHAP authenticated and obtained an IP address from my ISP.

At first I thought it was a DNS issue, as when I try to load a web page in the browser, it gets stuck at the "Looking for site" stage, but even if I know the IP address of the host I'm trying to connect to, it still doesn't work.

I have ruled out the hardware as a cause by replacing everything with like-for like parts i.e. I left the router switched off overnight, and then connected up a different router and different phone cable, and plugged it straight into the test socket of my BT master socket via a different microfilter. Exactly the same result. I'd be surprised anyway if the physical connection was an issue, because the router stays pretty consistently synced at 4500 up / 900 down or thereabouts, even while this problem is occurring.

My workaround solution so far is essentialy to reconnect over and over until at some arbitrary point I am able to view web pages again. Thankfully I don't have to reboot the router every time. I have a Netgear DG384G v4, and it has a "Test" button in the admin interface, which disconnects from the internet and reconnects without dropping the physical ADSL connection (the little "i" light on the front of the router turns off and then on a few seconds later), so it's quite fast. Even still, I will have to repeatedly do this up to about 20 times before the connection eventually decides to start working again.

This would not be so much of an issue if it was only when I reboot the router, but it happens without me touching the router as well. I often find in the mornings that the connection has stopped working overnight, for example. But then I don't think it's due to the router being idle either, as I've had it happen to me while I was in the midlle of browsing web pages on a couple of occasions.

I reported the problem to my ISP, Aquiss, and they said that there is nothing wrong with the connection on their end. They suggested I upgrade the firmware on the router, but as I have shown above, it happens even with a different router. I'm not going to get BT involved as they will charge me £125 to have an engineer turn up and say "there's nothing wrong with it". If I wanted to test the connection with another ISP I'd have to cancel my Aquiss account and start one with another ISP, which I really don't want to do as I like Aquiss.

The other thing I'd mention is that I was on up-to-8-Mbps ADSL with Aquiss when this started, and since then I've been moved over to ADSL2+ and the problem is exactly the same as it was before. I've lived in this house for just over a year now, and have only ever used Aquiss here, although I don't think I had this problem for the first few months, and then one day it just started. Several months later, having tried all kinds of different things, I am now writing here in the hope that one of you guys might have an idea, or have experienced a similar issue.

Thanks, and sorry for the long post!
Tom
 
Hello Tom and welcome to the forums, where to start is the question..


Any fault that is intermittent is a real pain to locate.. One suggestion would be to copy and paste your router logs plus your router stats when this happens once connection is working repeat the copy and paste logs and stats. You need to log times and dates as you do this so to build up a pattern of events that leads to causing this fault.

Have you spoken to Aquiss recently on this with intermittent fault?
If you don't keep the ISP updated they will not know it is continuing.

If you post some stats but send them to Aquiss also we can see if we spot something that is causing it.
 
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I have been having EXACTLY the same problem in recent weeks; VISPA say they cannot identify why the line syncs but no data downloads; one really queer thing I found; I can SEND an email (although very slowly), even when I cannot "find" the pop3 server to download any mail on the server!!!

They believe it is a fault with BT equipment at the local exchange, possibly water damaged cables, but so far there has been no news of BT fixing it.

My line went down during the heavy showers yesterday and only returned several hours later, and after a router reboot; somehow the DNS settings on the router got wiped as well!!!
 
Hmm this could be a million and one different things and as others have said, it's always a pain to pin down. One thing worth checking, as somebody else has mentioned, is whether or not you're using a wireless link and to try a wired one instead if you are. Despite many years of development, Wi-Fi is still known to suffer from problems and can cause all kinds of unusual behaviour from ping spikes to brief losses of connectivity.

It might also be worth checking what MTU setting you have on your router and seeing if it matches the ISPs (Aquiss might tell you what they recommend if you give them a mail or forum post). Granted this probably won't solve the problem but it might help a little. I'd also suggest using the OpenDNS.org servers instead of your ISPs own and trying a different web browser (Opera, Firefox) just to test.

Failing all that, when the problem occurs, you might want to try BT's test login as mentioned in this article on page 3: http://www.ispreview.co.uk/articles/adsltips/ . Your ability to test is limited but it might help rule out whether your ISP or exchange/bt is at fault. Always backup your router settings before making any changes.
 
Check you have got the latest firmware on your router.

I doubt it will reveal anything, but the Netgear's PPP daemon can be run in debug mode to view the various control messages such as the chap handshakes with BT's and then the ISP's radius servers -might be worth trying when you are having problems getting a working connection to see if you can spot anything abnormal.

http://192.168.0.1/?todo=ppp_debug (this will also drop and reconnect PPP -Rebooting disables debug mode)

The ppp debug log is displayed at http://192.168.0.1/ppp_log

ppp_log gets very large due to the router sending LCP echo requests every 30 seconds and will use up all the router's temporary storage space after a few days, although you can telnet into the router and delete it, to avoid having to reboot. http://192.168.0.1/?todo=debug to enable telnet. From a telnet client rm /tmp/ppp_log to delete the log.
 
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Hi,

Are you running Vista OS? Could it have been a auto-update that has caused this problem. Also a through antivirus and malware scan may reveal sonething. Clean out the registry might help.
 
Hi,

One other small point, run disk clean up, also check disk defrag to see if the hard drive need defraging. Getting rid of old cookies also will help and any un-needed rubbish will keep any pc running at its best.
 
Check you have got the latest firmware on your router.

I doubt it will reveal anything, but the Netgear's PPP daemon can be run in debug mode to view the various control messages such as the chap handshakes with BT's and then the ISP's radius servers -might be worth trying when you are having problems getting a working connection to see if you can spot anything abnormal.

http://192.168.0.1/?todo=ppp_debug (this will also drop and reconnect PPP -Rebooting disables debug mode)

The ppp debug log is displayed at http://192.168.0.1/ppp_log

ppp_log gets very large due to the router sending LCP echo requests every 30 seconds and will use up all the router's temporary storage space after a few days, although you can telnet into the router and delete it, to avoid having to reboot. http://192.168.0.1/?todo=debug to enable telnet. From a telnet client rm /tmp/ppp_log to delete the log.
I think the router will auto-erase the log file when it fills up so as to avoid problems, I know I've had this enabled because I couldn't figure out how to disable it :) . Not really looked. Very useful data output but it might be hard to understand.
 
Hey all,

Thanks for all the replies, it's nice to have a few more ideas after all this time!

I'll tell you what I've managed to do so far:

* I've got my stats and logs as requested. Can't see any way to attach files here, so have some links instead:

http://tomandpete.co.uk/router_stats_working.txt
http://tomandpete.co.uk/router_stats_not_working.txt

* I also tried disabling the firewall on the router, which had no effect.

* I can confirm that the problem happens for multiple computers, some running Win XP and some running Linux, some using the wired network and some using wireless, so I'm ruling out connection settings etc on the computer side.

* The MTU thing was interesting. I read about how this might be too high, but in fact it was set to 1492, which seems to be lower than what some people have it at. Anyway I have tried it at 1492 and 1500 and the results are just the same as ever: sometimes it works, sometimes it don't :) However, the router mentions that 1492 is usually the right setting for PPPoE, but I am using PPPoA. This led me to try switching over to PPPoE, and it seems that I don't get any connection at all when using PPPoE (internet light eventually goes red instead of green). Is this normal? I was under the impression they should both work, but I don't know a lot about them admittedly.


I haven't spoken to Aquiss about this recently because we had reached the point where they were completely out of ideas and were basically suggesting it is my problem. I don't think it is, but I'm not ruling it out just yet... although frankly I don't see what's left on my side that could be broken.

Captain_Cretin, it's interesting that you have the same problem! I'll have to try that sending email thing. The fact that this has been happening to me for months suggests that it's not a widespread problem at my exchange... in fact I could be the only person with the problem, I have no idea. I'd love to be able to get BT to look at the cabinet, but I really don't want to end up with a callout charge to pay.

I will post again when I've got round to the PPP debug, but it will probably be tomorrow as I have to get to work! :D

Thanks again for the suggestions,
Tom
 
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your router the Belkin NI?

looking at stats this one is interesting

Status: ShowtimeRetrain Reason: 8000
Channel: FAST, Upstream rate = 935 Kbps, Downstream rate = 4544 Kbps
Link Power State: L0
Mode: ADSL2+
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 9.9 6.2
Attn(dB): 53.0 30.3
Pwr(dBm): 0.0 12.9
Max(Kbps): 6820 956
Rate (Kbps): 4544 935

My bold shouldn't there be some power at least my stats for belkin N1 are

Link Power State: L0
Mode: ADSL2+
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 10.8 5.6
Attn(dB): 38.5 21.5
Pwr(dBm): 16.5 12.7
Max(Kbps): 6624 1000
Rate (Kbps): 5301 999

which shows power on both down and up might be worth copntacting Belkin support and god help you as my last contact with them i told them wasn't very helpful.
 
No, my router is the Netgear DG834G v4, however they both seem to be using the same program to output the stats :)

That is indeed curious about the power being 0dBm downstream, although I notice it's the same for when the connection is both working and broken. Anyone know more about the power stat? Sounds like something that should have a value > 0, but I don't really know. Perhaps it's being measured wrongly?
 
I will ask around see if I can find out more do you know if your set as 8meg or the full 24meg on adsl2+?
 
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Yes you have a long line looking at your ATT I am also on 24meg shorter line. I am going to get the adsl nation faceplate to replace my iplate for the noise on the bt network
 
I think the router will auto-erase the log file when it fills up so as to avoid problems, I know I've had this enabled because I couldn't figure out how to disable it :) . Not really looked. Very useful data output but it might be hard to understand.

Short of a reboot, I don't think it does. However the router can store a fair amount of data before it falls over. I can't remember how to disable it, or even if I ever worked it out, but as I recall deleting /tmp/ppp_log stops it logging until the next time PPP restarts. EDIT:- I just had a quick look and I think deleting /tmp/debug and /tmp/ppp_log should do it.

Probably the most useful things to check are that the router authenticates with both BT's radius server and then the ISP's radius (assuming BT's system still works that way) and the names of the radius servers in the CHAP Challenges. And if the LCP echo requests are still receiving a response when the connection appears dead.


Oh, I guess I should mention that The lines starting "sent [Chap Response" contain the user name plus a hex code which is a hash of the password

sent [CHAP Response id=0x1 <hash of password (hex)>, name = "UserName@skydsl"]

not sure it would be possible to decrypt it, but better to edit out the hex code between the "<>" before posting it.
 
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Hmmm the Pwr(dBm): 0 reading is interesting.

Generally, if you weren't having disconnection problems, then I would say it was just the routers inability to read that statistic from your telephone exchange and is nothing to worry about. However with disconnection being an issue then I'm not so sure. Would like to know if it occurs on other routers you have tried.
 
mrtom,

Can you fire a ticket into our support desk, mark for my attention, so I can review your history and see if we can move forward with a solution.

ADSL2+ is a funny beast, and many brands of routers are just not playing very well with it, especially with BT current deployment. 42% of our customers we have had to revert back to ADSL1 to get better performance, better sync and more importantly keep line stable.
 
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