DNS problems with Technicolor TG582n

[#1]

I'm using my Plusnet supplied TG582n router as my DNS server and have been experiencing intermittent loss of DNS over the last few weeks.
When this happens I still have connectivity and can connect to known remote hosts if I use the correct IP address instead of a hostname.
When I temporarily reconfigure my PC to use one of the Plusnet DNS servers (e.g. 212.159.6.9) during the outage then I can resolve addresses but not when I switch back to using my router (192.168.1.254) so it looks like it could be a problem with the DNS server in the router.
The problem usually lasts for a few minutes before things return to normal.
Any suggestions on how I can fix this problem?

[#2]

You are not alone. There have been various reports recently, and a number of threads here, describing similar symptoms cured by setting DNS locally in the device.
That includes me, my main PC is currently configured to directly access the Google DNS servers.

[#3]

There have been a few threads in the past where the DNS server in the router appears to stop responding completely, possibly limited to things connected over wireless:
https://community.plus.net/forum/index.php/topic,116178.0.html - Plusnet were investigating it in that thread, and wanted lots of extra data collected, but I don't know if that resulted in anything
https://community.plus.net/forum/index.php/topic,124871.0.html
More recently there was a thread with DNS server in the router incorrectly serving up 198.18.1.X IP addresses:
https://community.plus.net/forum/index.php/topic,134916.0.html

[#4]

Quote from: ejs

There have been a few threads in the past where the DNS server in the router appears to stop responding completely, possibly limited to things connected over wireless: https://community.plus.net/forum/index.php/topic,116178.0.html - Plusnet were investigating it in that thread, and wanted lots of extra data collected, but I don't know if that resulted in anything

I'm connected to the router via ethernet cable so it's not a wireless issue in this case.
I wasn't aware of this already having been discussed here - I must have used rather poor search terms when I looked earlier. I'd originally raised a ticket with Plusnet support and got the following reply

Quote

Unfortunately, this isn't something we can fully support you on. What I would strongly suggest is to contact our Community Forums as they may be able to support you better there

Considering that Plusnet must have been aware of this issue for some time I'd have expected them to at least acknowledge that it's a known problem and hopefully be making some effort to come up with a fix rather than leaving us to talk about it here.
This certainly looks like a problem with the DNS server in the router but the odd thing is that I've been using this router since April 2012 but only started to suffer from the problem over the last few weeks. I wonder if a firmware upgrade might help it's currently 8.4.4.J and I believe that 10.2.2.B is now available.

[#5]

The firmware update didn't help me. I think it's a bit more complex than a router-only issue though.

[#6]

It would probably be useful for anyone experiencing DNS problems to do some tests at a command prompt with nslookup to determine if they are getting no reply or getting those 198.18.1.X replies.
The problem(s) with the router's DNS server may only occur under certain conditions as only a very small number of people seem to encounter the problem(s). But it's still quite clearly a problem with the router.

[#7]

Quote from: ejs

It would probably be useful for anyone experiencing DNS problems to do some tests at a command prompt with nslookup to determine if they are getting no reply or getting those 198.18.1.X replies.

dig bbc.co.uk (using the router for DNS) just timed out but dig @212.159.13.49 bbc.co.uk returned a valid address confirming that I still had connectivity and Plusnet's DNS was working.

[#8]

I meant to reply here, not the other thread:
This has been the cause of an Ubuntu PC that has been very slow (browsing) and has not been updating the operating system properly for the last year since we've had this Technicolor router.
Symptom:
When you do update in Ubuntu's aptitude, it hits lots of its software update sites and the last one or two it ask for (e.g. uk.archive.ubuntu.com or such like) the DNS IP address it is told to go and use is 198.18.1.132 or such like.  And obviously 198.18.0..0 being private address space, it finds nothing and so the update of the PC's operating system times out and fails!  Nightmare.
Cause:  DNS server on Technicolor router sometimes returns rubbish IP addresses
Solution:
I have stopped the PC using DHCP and thus stopped it using 192.168.1.254 as the DNS server and instead I hard wire Plusnet's DNS servers into the PC and now the PC updates works properly and is much, much faster for browsing.
Is there a fix for this router? A firmware update?  Or can we get a replacement router model from Plusnet?

[#9]

It's interesting in the sense that no-one has previously reported Ubuntu or other Linux systems triggering the problem.
Anyway, disabling the WANDownSpoofing should stop the 198.18.x.x IP addresses from appearing. Requires accessing the router with telnet.

:dns server config WANDownSpoofing=disabled
:saveall

[#10]

Thanks. I've done that now.
It was whilst I was using aptitude and doing an update that I first noticed the issue.  The update makes lots of requests for different DNS names and the last one just sat there saying, "trying to contact 198.18.11.1" or such like.  I stared at it whilst waiting and realised it was a private address space address and that's what made me start looking into this router.  
Not that interesting, but seems to suggest if you make lots of DNS requests to the router in quick succession, it might give you a duff spoofed one for the last request or two.
dick:quote

[#11]

I've had a good run with PlusNet for exactly 10 years and 3 days and always had the top package. I have both PlusNet Fibre and international phone package. But when I can't access my bank account or even the BBC for about 4 or 5 days now due to getting "This Page can't be displayed" or unformatted screens it's probably time to move on.  BT Infinity cannot be worse than this. Fixing problems that they created one at a time is not good enough.

[#12]

I'm saving up screen snips of all the failed pages ready for when I transfer to BT and then if PlusNet try to impose any penalty for leaving I will say they are in breach of contract for not providing me the service I am paying for. It is not professional for an ISP to expect customers to change setting on their PCs to fix their problems.

[#13]

Mike, this is an issue with the hardware rather than your Internet connection itself. The same thing would probably happen should you use the Technicolor router on a BT connection. The issue has not been created intentionally, and we are working through our options for resolving it.
Problems happen, and whilst I'm sorry you're victim to this particular issue, I don't think something like this is reason enough to exempt you from your contractual obligations.
I'm not in a position to do it at the moment, but as soon as I get the opportunity, we'll push a config update to your device which should resolve the problem.

[#14]

Quote from: Bob

I'm not in a position to do it at the moment, but as soon as I get the opportunity, we'll push a config update to your device which should resolve the problem.

Config pushed, so all should be well now?

[#15]

I'm afraid I don't agree Bob. A contract has two parts with responsibility equally placed on both sides.
As a customer, my contract with PlusNet is to make payment for the service I receive, and that I have been doing. My part is complete.
PlusNet's responsibility under the contract is to provide the service, which in my case includes the modem router PlusNet provided. Nearly a week of constant failures that stop me following the sports, hobbies, interests and more significantly access my bank accounts is not providing the service customers are paying for. When we cannot access our bank accounts we cannot make payments and have to go elsewhere to access the Internet. I consider that to be a breach of contract on your company's part. The problem is not caused by the customer and the time we spend (days) running virus scans on our PCs and laptops and searching for solutions ourselves thinking it is our fault is something that your side does not see. Technical issues are not the customer's responsibility any more than the customer's ability to make payments is your responsibility. Not being able to access PlusNet's own website or find this sort of thread only increases to anxiety.
Whilst I have been reading and comparing the terms and conditions for BT and Sky services, and now returned to my PC I can confirm that all seems to be working at the moment.
Nevertheless, thank you for sorting this for me, Bob, as in the main I have been very pleased with PlusNet or I would not have remained with them for over 10 years.