Router or DNS problem?

[#1]

Hi All
Have been having intermittent but ongoing issues with dropped internet connetions for about 2 months now, and had posted previously about suspected DNS issue. However, having looked at posts in other threads am not so sure.....
Background: problem manifested itself at around same time as upgrade to 21CN
Problem: Internet connection fails randomly and states DNS problem.
Resolutions: Usually try the Windows 7 or Plusnet Assist fixes, but always eventually requires turning router off and back on. This always works.
Attempted solutions: Initially changed DNS settings to Plusnet. Same thing happened; Changed DNS this week to Open DNS and followed followed info to flush router. Same thing continues to happen. DNS settings changed in both router and pc. When no connection, have tried accessing BBC via IP address at 212.58.341.131 that was posted on another thread. Cannot access that.
So, having tried other DNS settings and not being able to access directly to IP address when the fault is present, does that narrow it down to a router fault? Am using a Netgear wireless DGN 2000 modelt which is less than two years old, and which never had any connection problems prior to this.
Any advice much appreciated.
NewStu

[#2]

The mention of DNS issues from Win 7 tends to be more symptomatic of being disconnected from the net rather than a description of the cause of the problem.
If this does continue to happen we'd advise using the fault trouble shooter here: http://faults.plus.net

[#3]

Next time it fails open a cmd promt and try tracert ntp.plus.net. You should get something similar to below. If it fails it might point to where the issue lies.

C:\Users\John>tracert ntp.plus.net
Tracing route to ntp.plus.net [212.159.13.50]
over a maximum of 30 hops:
  1     3 ms     1 ms     1 ms  dg834 [192.168.0.1]
  2    33 ms    16 ms    15 ms  lo0-central2.ptn-ag02.plus.net [195.166.128.206]
  3    14 ms    14 ms    24 ms  gi2-12-221.ptn-gw01.plus.net [84.92.5.145]
  4    14 ms    14 ms    14 ms  vl55.ptn-lb01.plus.net [212.159.2.124]
  5    15 ms    15 ms    14 ms  cdns02.plus.net [212.159.13.50]
Trace complete.

[#4]

Adam and Jelv
Thanks for the suggestions. Will try the fault troubleshooter next time it happens, although will presumably only be able to do so once have re-booted the router.
Have tried the tracert previously when the fault is present and it failed. Ping failed too, but will do so again just to check.
Guess that might suggest a general internet fault as opposed to a DNS issue?
Will have a go this evening when home from work and post results.
NewStu

[#5]

At which step did the tracert fail? That is highly significant. It's also significant if it gets past step 1 if it manages to show the names associated with the IPs.

[#6]

The tracert failed when I was using the automatic DNS settings in April. After that I switched to the Plusnet ones and things were more stable for a couple of weeks, but then reverted to failing most days.
NewStu

[#7]

These were my previous results
C:\Users\Stuart>tracert www.pls.net
Unable to resolve target system name www.pls.net.
C:\Users\Stuart>ping www.plus.net
Ping request could not find host www.plus.net. Please check the name and try aga
in.
C:\Users\Stuart>

[#8]

Correction to what I suggested earlier. Instead do
tracert 212.159.6.9
The output should be very similar.

[#9]

Will do that at next failure, which may be when i get home this evening.
thanks for the advice

[#10]

Hi ALl
Just to update, have not had recurrence of problem since 1st June, about a day after I switched to OpenDNS. Hopefully issue now resolved.
Thanks for advice given
NewStu

[#11]

I am also using a DGN2000 and having intermittent loss of DNS services. My DGN2000 is configured to get the DNS Server addresses automatically via DHCP. There appears to be an occassional compatibility issue between the DGN2000 and the PlusNet DNS Servers that confuses the DGN2000.

[#12]

Could you elaborate on the way that this "compatibility issue" displays itself?

[#13]

The router cannot resolve any DNS requests that would normally be forwarded to the Plusnet DNS. All other router functions are OK. The ADSL connection is OK. If you restart the router, DNS requests can be handled OK.

[#14]

Next time it happens, find out which Gateway you are on using the IP address, try http://212.159.3.14/@gateway/
Make a note for future reference, in case there is a pattern.
Then login to the modem/router, on the main menu, under Maintenance select Router Status and at the bottom select  Connection Status.
Click on Disconnect to drop your PPP Internet session.
When it's disconnected, (you may have to refresh the page to see it), you can then click on Connect.
In your browser you can then Check which Gateway you are now on. This is known as doing a Gateway hop.
If that doesn't work/solve the problem, or if it's occurring too frequently, do a Disconnect and then set the DNS servers manually on the Basic Settings screen - change from Get Automatically to Use These DNS Servers as mentioned in  this thread as it sounds like a similar problem as has been seen on some recent Netgears (not just the router being used on fibre). Click Apply before leaving the screen.
Just a further thought, has this only been happening lately, in the early hours? It could be caused by the loss of PPP session as a result of BT network maintenance eg. as detailed here. There has been work in some previous weeks if you look back through the archives. I've seen several posts now with people having funny problems with reconnecting after this work. See this post for example.

[#15]

Hi Markitz
I changed my DNS to Open DNS and went through the flush process that it recommended and have not had any problems since, which is about 14 days now. Prior to that, I was having daily problems and had tried a variety of fixes, including using the manual PlusNet DNS settings rather than automatic detection. Had to switch router off and on to connect, which was tedious.
Worth having a look at at link below
http://www.opendns.com/home-solutions/
NewStu