Repeated DNS issues with Fibre broadband.

[#1]

Hi @jphdavis 

Looking at the ticket the agent left, I see you had a conversation about trying the local network without the switched - can you let us know if this has made any significant difference? 

Thanks, 

MoR

[#2]

Update on this problem:

1. I have replaced DSL Router with newly supplied but otherwise identical one
2. I have removed master socket faceplate and plugged router into filter which is plugged into test socket

This morning at around 7am the DNS service failed again and I was forced to reboot the router at around 7:20-7:30, so neither of these things have fixed the problem.

Prior to rebooting I did the following checks:

1. Looked at DNS server ids listed on router broadband page
212.159.6.10 / 212.159.6.9

2. Pinged both DNS server IP addresses
Both came back within 10ms with response

3. Ran IPConfig on Windows to check DNS server
Showed as 192.168.1.254 (correctly pointed at router)
Did similar check on Mac with same result

4. Ran NSLOOKUP google.com on Windows (ran it a few times with same result)
Failed with:
Server: dsldevice.lan
Address: 192.168.1.254
DNS Request timed out. timeout was 2 seconds

5. Reconfigured DNS on Mac (wifi) and Windows (ethernet) to point to 212.159.6.10
Tested this on Mac and Windows. DNS services started to work, I could browse internet.
Once reset to default, DNS stopped working again

6. Logged into router advanced settings and restarted router
Mac and Windows machines started successfully getting DNS response, I could browser internet
Checked settings on router and Mac/Windows and nothing had visibly changed

Note:
I have 16-20 devices using DHCP to get ip addresses from router, if this is an uncommonly high number it may be putting pressure on router resources or software bugs.

Conclusions:

1. Plus.Net DNS server is still accessible and functioning from my systems when fault occurs
2. Line is functioning correctly despite router DNS service failing (ie no indication its a line problem)
3. Problems only occur for devices using router for DNS service
    * Pointing directly at google 8.8.8.8 / 8.8.4.4 or at plus.net DNS both work fine
4. Problem seems to be directly related to the router
    * It's possible that line drops trigger router problem but it could be co-incidental
5. DNS only occurs when router is involved and problem is consistent with two routers
    * Problem is systemic router hardware or software issue, most likely software

So, my best theory is, there is a bug in router firmware that when triggered causes the router DNS redirect service to fail and stop passing requests or results correctly, which results in no response from router to NS Lookups.

Trigger may become more likely when larger numbers of devices are connected or when line drops occur, or it may be something completely different.

The easiest way to test this would be to take a different model of router and configure it to work with Plus.Net and see if the problem goes away. I have at least one other fibre broadband router which I could test using settings here: https://www.plus.net/help/broadband/broadband-connection-settings/#what-settings-should-i-use-for-fi...

Another alternative would be to run some kind of diagnostic on the router once the problem occurs and see if the DNS service is still running/working. though to be honest it pretty clearly isn't. I don't know enough about router system design but if there is internal logging that could be enabled it might show the fault.

Currently I am without a phone line and have been asked to continue this for 3 days, which is a bit worrying as I won't even know I'm missing important calls (I don't have supplier answer phone service setup).

[#3]

Hi @jphdavis, thank you for doing those checks.

If you do have an alternative router you can try, please can you connect this for the time being so we can help narrow down where the issue lies?

Let us know how you get on.

[#4]

I do have an alternate router which may be configurable to work with Plus.Net, I will have a go at setting them up and see if it can be made to work. I'll aim to find time to do this by end of play Wed at latest.

Jules

[#5]

Great thank you, let us know how this goes.

[#6]

@LaurenB  I have now successfully installed the replacement router and plugged it back into the normal ADSL socket (instead of test socket), so my phone is working.

Line seems to be working well with the new router.

I would propose that the "super stable" mode now be turned off to see whether the DNS problems recur with the replacement router, and compare outcomes to the existing situation.

Once super stable is back off and the lines been running a week or so, it would be interesting to look at the chart (as above) to see if line is dropping.

Thanks

Jules

[#7]

Thanks for getting back to us and for connecting the replacement router. To be honest, for the meantime I would leave things as they are and monitor it for the next few days, as if the issues persists we'll likely need to go down the route of an engineer. If everything continues to work well, then we'll take it from there, let us know how you get on.

[#8]

Having replaced my Plus Net router with a third party one the problems have resolved. This would strongly suggest that something is wrong with the router, as my Plus.Net router was replaced by a second one, I'd suggest this implies the problem is with the firmware or hardware design, not a specific router. It could be the bug only appears with certain local network conditions or with particular characteristics of the line.

I'd suggest logging the problem with whoever is responsible for the HW/SW of the router. Given how much this problem has been reported on the community site, it's pretty disappointing that Plus.Net seem to be making no effort to fix it. Plus.Net claims to be high quality / high customer service, my experience so far has been lots of helpful people that has led to nothing being actually resolved with my fault, and my internet is also slower than with previous supplier.

[#9]

Hi @jphdavis,

Thanks for letting us know how you got on, I'm glad this is working for you.

All feedback will be passed on to the relevant teams who will be working on the router issues as previously mentioned on other posts within the forum.

Thanks.