Latest firmware not honouring manual DNS settings

[Warpcoil]

My router is now running SG4K100208, at least since it was reset by a recent power outage.

Since then connections have been flaky and some features no longer work, which I've finally tracked down to the clients using the wrong DNS servers.

I have the primary and secondary IPv4 servers set as 1.1.1.1 and 1.0.0.1 on the router, which was being corrected reflected via DHCP to the clients.

However, since the firmware "upgrade" the router's configuration screen still shows these servers, but all the attached clients are using 79.79.79.79 and 79.79.79.80, which are the default Talktalk internal DNS servers, which don't support secure DNS.

I can prove this is the reason the client features are't working, by setting one with a static IP address and manually inputting the correct DNS servers, but it should be necessary to disable DHCP to have secure DNS.
It was working fine before the "upgrade" so that seems to be what broke it.

If you think you're running manually configure DNS servers, check your clients and see what they're actually doing.

[KeithFrench]

In the Hub 3 (I know that you do not have one), the DNS tab has now reverted to 192.168.1.1 by default. I assume, therefore, that the next version of firmware for your hub will follow suit.

[KeithFrench]

That DNS page has been populated by the TT DNS network servers for a couple of versions now. It sounds like yours just got corrupted; that is all.

[Warpcoil]

Without rolling back the firmware level, I have no way of knowing if that screen existed before or not, though I've never seen it before.

What I can confirm is, prior to the "upgrade" all my clients were using the Cloudflare servers, including Secure DNS.

Following the "upgrade" they switched to using the TT servers, and Secure DNS failed.

If you check the screenshots I added earlier you will see that the router said it was still using the Cloudflare servers, which may or may not have been for it's own purposes, but it wasn't passing that in the DHCP assignment to the clients, which is the whole point.

[KeithFrench]

Hi @Warpcoil 

That screen has always been there, it is just in recent versions the TT network DNS servers have been added to it. As I said before these are the addresses handed out to your clients via DHCP. If you monitor the DHCP process, you will see that I am correct.

[Billx]

Hi, @Warpcoil 

I conducted a second experiment.

Starting with,  Primary DNS Server 79.79.79.79 and Secondary DNS Server 79.79.79.80, in all 3 of the above referenced locations,

I set, Primary DNS Server 1.1.1.1 and Secondary DNS Server 1.0.0.1

in the 'DNS' tab of the 'TalkTalk Wi-fi Hub 2' section, as you show in your last message.

The 'Device Info' tab of the 'TalkTalk Wi-fi Hub 2' section and 

the 'DNS IPv4' tab in  the 'Internet Connectivity' section remained what they were before,

Primary DNS Server 79.79.79.79 and Secondary DNS Server 79.79.79.80 .

So, a similar question remains now:

Did you leave the previous existing setting in the 'DNS IPv4' tab in the 'Internet Connectivity' section?

as they were, as Primary DNS Server 1.1.1.1 and Secondary DNS Server 1.0.0.1?

In that case, settings in both locations are/would be required.

Bill

[Warpcoil · Accepted solution]

Correct DNS
With the correct DNS Server addresses entered onto this new page, and the router rebooted, everything is finally back working as it should, including Secure DNS.

Why this screen has been added, and the input on the previous page ignored, is anyone's guess.

[KeithFrench]

Hi @Warpcoil 

TalkTalk do not publish any.

[Warpcoil]

I have made the change in the additional screen, the one that somehow got pre-filled with the TT DNS server addresses, changing those to the Cloudflare addresses, which hasn't yet made any difference (yet), either to clients already connected, or to new clients being connected.

I say "yet" as I haven't had an opportunity to reboot the router, due to time-critical services running over it.
I will reboot overnight and see if this fixes the issue.

If it does then we're good to go.
If it doesn't then I would need the firmware rolled back, to a version that works.

Is there any Release notes for the new firmware that lists what issues it was meant to fix?

[KeithFrench]

To get a firmware rollback, you will have to request on here that TalkTalk do this for you. They will probably have to get their Devices team to do that for you.

[Warpcoil]

Prior to the "upgrade" everything was happily using Cloudflare DNS.
Following the "upgrade" without me making any changes, every has switched to using TT DNS.

I didn't enter the TT DNS addresses on any page, though they have appeared on a page I've not seen before.

I understand the argument regarding using the router as a local DNS server, though this only has an advantage if the address being queried is already cached and is still valid, which is unlikely, and the router isn't capable of handling Secure DNS anyway, so that's moot.

Note that the routers default would be to have the clients use the TT DNS, and not itself.

This leaves two questions:
- why did the upgrade change the DNS behaviour?
 - how do I get it back to working as I need it to?

I can't reboot the router until the end of the day, as there's currently time critical processes running.

[Billx]

Hi, @Warpcoil 

Since previously, under the default position, the router advises the clients, to do DNS via  79.79.79.79 and 79.79.79.80 ,

and you are now changing that to 1.1.1.1 and 1.0.0.1, in the 'Internet Connectivity' section,

I can't see a problem doing the same,

in the 'DNS' page under the 'TalkTalk Wi-fi Hub 2' section., that still has  79.79.79.79 and 79.79.79.80.

In other words, both places need to be changed.

Bill

[KeithFrench]

No @Warpcoil, but what I said in my previous post is how DNS needs to be set up to maintain an efficient DNS hierarchy. Please do that & tell me what happens.

[Warpcoil]

Thanks @Billx , at least you're seeing the same inconsistency, so it's not just me or my individual router.

[Billx]

I conducted the experiment, to see what's happening

Logging into the Wi-fi Hub 2, and going to Advanced, then

firstly, clicking 'TalkTalk Wi-fi Hub 2', defaults to the Device Info page.

The following shows here:

Primary DNS Server      79.79.79.79

Secondary DNS Server 79.79.79.80

Secondly, licking 'DNS' under the same 'TalkTalk Wi-fi Hub 2' section

the following shows here, the same info:

Primary DNS Server      79.79.79.79

Secondary DNS Server 79.79.79.80

Thirdly, navigating to the 'Internet Connectivity' section

the following shows here, the same info:

First IPv4 DNS Server    79.79.79.79

Secondary IPv4 Server  79.79.79.80

So 3 locations, having the same default info.

Now the experiment

In the 'Internet Connectivity' section,

I set new Primary and Secondary DNS Servers, 1.1.1.1 and 1.0.0.1

The new info in the 3rd location, was automatically copied to the 1st of the above 3 locations.

The info in the 2nd location remained as was, 79.79.79.79 and 79.79.79.80 .

So, the question arises, does the user also have to change the info in the 2nd location?

To also 1.1.1.1 and 1.0.0.1?

or to 192.168.1.1? When one wants to set special DNS Servers?

(I've now reversed the above.)

Bill

[KeithFrench]

Hi @Warpcoil 

The Internet Connectivity DNS config is correct, but your TalkTalk Wi-Fi Hub DNS settings are wrong. This is the DNS server address handed out to your clients by the router using DHCP. Setting them like you have done means that the router is using Cloudfare or whatever, whilst you are telling the clients to bypass the router & use the TalkTalk network DNS servers. They should always be set to the router's IP address on this page, which is normally 192.168.1.1. This will always be a bit faster, as the clients' DNS server is the closest one to them, on their subnet. 

[Warpcoil]

That rings a bell, though to be honest I couldn't be sure, other than it wasn't ©2025!

I did backup the router config to "somewhere safe" and just browsed the Router web pages to find the backup option in the hope it would remember where that was, which it didn't ;(

However, what I did find was an extra Static DNS page that I don't recall seeing before, and that has the default TT DNS server addresses, though it says "leave blank for default".  It confusing because both the page I'm used to seeing and the device network status page are showing the correct (1.1.1.1, 1.0.0.1) addresses.

I've now changed that Static DNS screen to the correct addresses, which didn't make any immediate difference, but might if I reboot th e router. Correct DNSWrong DNSCorrect DNS

[KeithFrench]

Hi @Warpcoil 

@Mandisa-TT has asked me to help you. Before the power outage what firmware was the router running - V206?

[Mandisa-TT]

Hey @KeithFrench I would appreciate any advise on this.