TV Causes DNS error on all other devices

[#1]

I havent been able to easily find others discussing a similar issue so here it is.

When my smart tv is on, all other devices get DNS errors. Wired and Wireless. As soon as the TV is switched off they all work again fine.

It doesnt seem to be an issue with bandwidth as there is much heavier streaming going on with various using PC's etc throughout the home during the day. As soon as the TV is switched on to it's home screen everything get DNS errored.

I have tried splitting my channels to test various configurations and have tried wired and wireless connections across various devices, including the TV and only seem to get the same result. TV on = no internet activity for anything else.

I've run out of ideas now and hope someone can help. If it helps I have a plusnet hub one.

[#2]

is the TV getting its IP address from the Hub One via DHCP or does it have a static IP ?

Either way , what IP address does the TV claim its using ?

[#3]

udhcp-1-14-1-
00:09:df:ae:ae:40
192.168.1.89

The above is created right away but the below also seems to pop up on the network.

android-dhcp-9
1c:fe:2b:b3:40:70
192.168.1.83

[#4]

Can't see anything wrong there.

Can you post the results of an nslookup of bbc.co,uk both with and without the tv connected

[#5]

Tv off

TV off

TV on

TV on

[#6]

Some further info. I have noticed that if something is running when the TV goes on it tends to continue running fine. i.e. a video call or online game. But if these are turned off and then on again while the TV is still on they get the DNS error.

[#7]

That would fit with a DNS failure. The running application would likely have already done the lookup and will continue using the ip address.

What version of the firmware does your Hub one have ?

There was an occasional  dns problem with an earlier firmware but it was not a consistent problem. Maybe something to do with your tv is triggering it ?

[#8]

Plusnet Hub One | Software version 4.7.5.1.83.8.263 | Last updated Unknown

Im not sure how to update it if this isnt the latest version?

[#9]

Actually there's a way to prove whether it's the router dns problem.

With the tv connected try

nslookup bbc.co.uk 212.159.13.49

That will bypass the router dns cache and go directly  to the Plusnet dns server. If that works then its definitely the router

[#10]

With TV connected

[#11]

Yup, that looks like it is the router Dns problem. Why the TV is causing it, I've no idea, never seen anything like that before. 

You can't manually update the firmware, it's pushed out to the routers via tr069 from the Plusnet servers. There is a rollout currently in progress but like most firmware updates it's staggered and doesn't update all devices at once.

I'm going to tag one of the Product specialists and see if he can push the updated firmware to your router  more quickly.

@bobpullen  strange one this ! Any chance you could push the latest firmware to @alsayeds router to see if it fixes the problem. 

[#12]

There is a possibility that the TV carries it's own DHCP and DNS servers. When your other devices attempt to renew their DHCP IP leases, the TVs DHCP server might be replying with its own approval and then in its reply, sending the ip address of it's own dns server.

Sounds a bit long winded but it is possible.

When i was working on my own DHCP server i included a basic monitor to see what was happening in real time. Sure enough, when one of our phones connected to the network my server would also reply along with the HubOne. Did it cause DNS problems? absolutely. She kept moaning about her phone not working and so i had to disable my dhcp service. To date i've still not included a feature to reply to ignore certain devices..

[#13]

There is a possibility that the TV carries it's own DHCP and DNS servers. When your other devices attempt to renew their DHCP IP leases, the TVs DHCP server might be replying with its own approval and then in its reply, sending the ip address of it's own dns server.

@7up I did think about that possibility but you can see from the nslookup , that the request is going to 192.168.1.254 i.e the Hub One.

[#14]

So, the TV is now on and no DNS issues across other devices. However, one of my google dot mini's now cant connect to my wifi.

This has happened every so often in the past but I have usually just set it up again from scratch. This time, it happened while I was troubleshooting the TV and it made me think that I may have only started getting DNS issues with the TV since I got a second Dot. I decided not to set it up again and instead tested the TV on and various devices and have no issues so far.

Maybe the two are not related but I thought it would be worth posting to update. There arent exactly many devices connected to my router, 6 max and only ever one of two being heavily used at a time, so I dont suppose there is an issue with bandwidth.

[#15]

Thanks for the update. I still its worth trying to get the latest update to your router as soon as possible. At least you have a workaround to get the TV working for the time being