Plusnet Hub One assigns wrong (non-existent!) DNS IP

[#1]

My hub is assigning every device in my house 192.168.1.12 as the DNS IP. No device with this IP exists. Pinging it gets no reply.

If I 'forget' the wireless network on my laptop or phone, and re-join, it works for 10-15 mins due to (correctly?) having the gateway IP (192.168.1.254) as the DNS, but sooner or later it changes back to 192.168.1.12.

Getting round it for now by configuring everything with static IPs, but it's not a happy state of affairs. I've factory reset the hub several times to no avail.

Any suggestions Plusnet?

[#2]

Hi, that's really odd that the hub is assigning a DHCP IP for the DNS in that way.

Beyond what you've already tried I;d suggest we look at replacing the hardware.

[#3]

Thanks Adam. Have just been on to the help team and that's precisely what they're doing. They said it was a 'spoof dns ip' but could not provide any further technical background to this strange behaviour. Shame as I'm curious.

[#4]

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@rockplough wrote:

They said it was a 'spoof dns ip' but could not provide any further technical background to this strange behaviour. 

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No idea what they mean by 'spoof dns ip'. It sounds like it's just configured to hand out that address but if clients are getting a sensible .254 to start off with then it's a bit weird. Hopefully the new router won't do the same thing.

[#5]

Well. Hooked up the new router today and same thing! Not only that but it was assigning 192.168.1.12 as the DHCP server IP, and gateway IP as well as the DNS. (screenshot shows correct DNS as i'd manually configured) Absolutely bizarre.

Spoke to Plusnet again and they have nothing to offer. What on earth is going on?

I considered the possibility of a rogue DHCP server, but when I scan the network the BSSID matches the router's MAC address.

I also wondered if somehow, something on my network was doing it. I reset the SSID and added the devices individually, one at a time. Still happens.

Devices are:

1. Windows 7 laptop

2. Macbook Pro

3. Samsung Galaxy S7

4. Samsung Galaxy S6

5. PS4

6. LG TV

7. Chromecast Audio.

I asked Plusnet if they could escalate this, if they had a team who look into these things, but they could offer no remedy.

Does anyone recognise this strange router behaviour, or have any ideas?

[#6]

Worth checking your network adaptor settings. On the Windows 7 PC, go to Network and Sharing Centre, right click on the appropriate network adaptor and select Properties, then highlight Internet Protocol Version 4 (TCP/IP) and then click on Properties. Make sure it is set to obtain IP address and DNS server automatically.

If you have it set to use a fixed IP address, change the Default Gateway and Primary DNS server to match the router's IP address, or set it to obtain these automatically.

[#7]

You could try using wireshark and have it capturing traffic until the 192.168.1.12 addresses appear. Then you could see the MAC and IP address of where they came from.

Or it might be possible to find the same information in Windows Event Logs, maybe you would need to enable DHCP client logging first.

Also, do you use any powerline network adapters? If you do, they might be connecting with someone else's network.

[#8]

@Jaggies The issue happens when TCP/IP are set to automatic. I can configure them manually and it all works fine, but is a workaround.

@ejs Thanks I'll try wireshark.

[#9]

Ok. Is my telly (192.168.1.68 / d8:bf:4c:01:14:0e) dishing out IP addresses?!

192.168.1.104 is my laptop. .254 is the router.

[#10]

Right sorry, it's the AQ Smartspeaker we have, not the TV.

Still, why is it doing this???

[#11]

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@rockplough wrote:

Right sorry, it's the AQ Smartspeaker we have, not the TV.

Still, why is it doing this???

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'cos it likes a laugh as much as the next device

Otherwise - I dunno. That's weird.

[#12]

This thread in itself is weird.

Why does @rockplough show as having only made 2 posts?

[#13]

Can't help you @Browni. Says 7 posts on my screen!

I've pulled the speaker power. Let's see what happens.

[#14]

Well, for those interested that seems to have sorted it. Mystified as to why it was doing this, but was thinking about a  new speaker anyway so it'll be going in the bin. Thanks for all the tips, particularly re Wireshark.