SmartHub DNS Server Faulty

[Axle]

A couple of weeks ago my phone, kindle, tablet and PC all failed to get Internet connectivity through my smart hub (ethernet, 2.4ghz and 5ghz WiFi all affected). My Samsung TV and Alexa still worked and the hub was reporting that the broadband connection was good. After some head scratching I just did a factory reset which sorted the issue. Until today when the same thing happened.  

After a bit of investigation it turns out that DHCP is only giving out the SH's IP as a DNS server with no secondary.  Using static settings on the affected devices using 8.8.4.4 (thank you Google) as a secondary gets the devices back online perfectly.  Before I spend hours on the phone to EE tech support has anyone else experienced anything similar or does it sound like a case of getting a new hub sent out?

Cheers. 

[XRaySpeX]

Eh, @bobpullen ? That is the WAN-side or Internet DNS. Just cuz they appear on the same page as DHCP settings doesn't mean they are connected.

We has the same confusion with the white Smart Router. The orginal black SH had DNS on a diff page, on Advanced > BB > Internet page along with TCP/IP setting, which is more sensible.

Who in their right mind would want to set some LAN-side DNS, if such a thing exists, over the Internet DNS?

[bobpullen]

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@XRaySpeX wrote:

Eh, @bobpullen ? That is the WAN-side or Internet DNS.

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No, it isn't. The WAN-side DNS addresses can be seen under Advanced Settings > Broadband. They will always show as EE's, even if you've specified third party DNS servers on the IPv4 configuration page in my screenshot.

Just cuz they appear on the same page as DHCP settings doesn't mean they are connected.

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Yes, it does. It is providing the ability for you to specify the DNS server that is allocated to client devices when they obtain their network configuration from the router using DHCP.

Who in their right mind would want to set some LAN-side DNS, if such a thing exists, over the Internet DNS?

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The end result is arguably the same. In fact, given the choice, I'd probably prefer the DHCP method as there are fewer points of failure. When a device on your LAN obtains a lease from the hub's DHCP server, that lease contains more than just the LAN IP address; it also contains things like the gateway address, subnet mask, and - of relevance here - the DNS server address.

For hubs that allow the WAN-side DNS to be changed, this is how devices end up configured: -

IP address: 192.168.1.50 (device IP)
Gateway: 192.168.1.254 (hub IP)
Subnet mask: 255.255.255.0
DNS address: 192.168.1.254 (also hub IP)

Then when a connected device carries out a DNS lookup it does this: -

Device --> Hub --> WAN-side DNS, i.e. the device DNS queries the hub and the hub then forwards that DNS request upstream to the WAN-side server and relays the response back to the client.

The way the EE hub is doing the DNS assignment, this is how devices end up configured: -

IP address: 192.168.1.50 (device IP)
Gateway: 192.168.1.254 (hub IP)
Subnet mask: 255.255.255.0
DNS address: 1.1.1.1 (third party DNS server)

Then when a connected device carries out a DNS lookup it does this: -

Device > Third party DNS server, i.e. it is no longer relying on the hub to act as 'man in the middle' and forward DNS requests; the client just goes to the third party server directly.

[XRaySpeX]

OIC! Thank you for explaining your view of things. I now see what you are getting at. When you 1st referred to "DHCP DNS" I imagined you were referring some sort of looking up of local domains which I can't see exist. Now I see you mean the delegation of WAN-side DNS but to local devices as & when they connect with default DNS settings.

However I can't see there is much between the 2 ways of allocating DNS: 

1. So  you save 1 hop in a DNS lookup but what's 1 short hop in a typical DNS chain?
2. It might no longer rely on the hub to act as the 'man in the middle' to forward DNS requests but it still relies on the hub to act as the 'man in the middle' to get out to the Net anyway. As you said earlier:

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@bobpullen wrote:

The hub assigning itself as the single DNS resolver shouldn't present problems as the hub should always be available for DNS querying (if it isn't, then you've bigger problems!)

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[Ewan15]

@bobpullen On the Smart Hub Pro I can search for the setting which takes me to Configure your IPv4 settings, however the DNS servers option is hidden

[charlienormand]

Same: I don't have this DNS Servers customisation option on my router settings, is there a special cheat code to get to them?! 

Smart Hub Plus, App Version : 1.13.1,  Firmware version: r1.35.0-R-1138091-PROD-83002

I want to switch to OpenDNS because the EE parental controls seem to be borked (as detailed - https://community.ee.co.uk/t5/Broadband-Landline/Information-Smart-Hub-Parental-Controls-not-working...)

[charlienormand]

I don't have this DNS Servers customisation option on my router settings, is there a special cheat code to get to them?! 

Smart Hub Plus, App Version : 1.13.1,  Firmware version: r1.35.0-R-1138091-PROD-83002

I want to switch to OpenDNS because the EE parental controls seem to be borked (as detailed - https://community.ee.co.uk/t5/Broadband-Landline/Information-Smart-Hub-Parental-Controls-not-working...)

[bobpullen]

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@XRaySpeX wrote:

However I can't see there is much between the 2 ways of allocating DNS: 

1. So  you save 1 hop in a DNS lookup but what's 1 short hop in a typical DNS chain?
2. It might no longer rely on the hub to act as the 'man in the middle' to forward DNS requests but it still relies on the hub to act as the 'man in the middle' to get out to the Net anyway. As you said earlier:

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@bobpullen wrote:

The hub assigning itself as the single DNS resolver shouldn't present problems as the hub should always be available for DNS querying (if it isn't, then you've bigger problems!)

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You're right, there isn't much in it and the perceived response time would be negligible (I could argue the same for changing DNS server addresses in general, although there are some valid reasons - like parental controls/ad-blocking etc.).

In a past life, I have seen a hub's DNS forwarding get into a tiff before, particularly where TCP DNS requests were concerned. Really unlikely though, and like you've highlighted, you've probably bigger problems to contend with in such an event.

One other benefit of the DHCP approach is for those that  might use a local DNS solution like Pi-hole. With the WAN method, the Pi-hole would see all requests originating from the router, whereas with the DHCP solution, the requests are seen to come from each of the individual devices on the network. This makes things like logging and device naming (at Pi-hole level) a little simpler.

@charlienormand & @Ewan15 - my screenie is from a Smart Hub Plus running v2.68.11. If you're on something earlier than that then it could be that the update hasn't reached you yet. Seems most round these parts are still on v.1.35.

[Ewan15]

@bobpullen Good to know it is on its way.

My Pro firmware is currently on r2.64.3-R-1213091-PROD-1

It will make a lot of people happy to be able to set up their preferred DNS 😉

[jimwsmith]

Ok so next challenge how to update the firmware?
I'm on 

Firmware version:

r1.35.0-R-1138091-PROD-83002

[XRaySpeX]

@jimwsmith : You can't! You wait for EE to fire it at you.