Dual ISP network issues now that Vodafone IPv6 is rolling out

[__graeme]

Apologies, this isn't a quick question .

Background:

I have 2 ISPs Vodafone and Virgin.

I run my own DHCP and DNS.

Virgin Router is 192.168.0.1 - Wifi and DHCP are turned off

Vodafone Router is 192.168.0.2 - Wifi and DHCP are turned off
Wifi is provided by separate Wireless Access Point
Via my DHCP server, devices on my network are assigned a gateway of either 192.168.0.1 or 192.168.0.2 and DNS of 192.168.0.11  

My DNS server on 192.168.0.11 uses googles DNS servers upstream. 8.8.8.8 and 8.8.4.4   
I have 60+ devices on my network. 

IPCONFIG snippet (redacted)

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : xxxxxxxxxxxxxx.co.uk
Description . . . . . . . . . . . : Atheros AR8151 PCI-E Gigabit Ethernet Controller (NDIS 6.20)
Physical Address. . . . . . . . . : 90-2B-34-xx-xx-xx
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : fd52:a81c:xxxxxxxxxxxxxx
Temporary IPv6 Address. . . . . . : fd52:a81c:xxxxxxxxxxxxxx
Link-local IPv6 Address . . . . . : fe80::d2:ef9c:7984:3155%11(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.0.25(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : 03 March 2020 00:41:21
Lease Expires . . . . . . . . . . : 11 March 2020 12:41:49
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.11
DHCPv6 IAID . . . . . . . . . . . : 2443nnnnn
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-CA-xx-xx-xx-xx-xx-xx-xx
DNS Servers . . . . . . . . . . . : fd52:a81c:xxxxxxxxxxxxxx
192.168.0.11
NetBIOS over Tcpip. . . . . . . . : Enabled
Connection-specific DNS Suffix Search List :
broadband

The issue:

Until very recently my network setup worked fine but today I'm getting website timeouts and various other issues. A quick look at my IPCONFIG on my desktop machine (and IP ADDRESS on my Linux machine) and I'm seeing IPv6 DNS server ahead of my DNS server. It seems that my Vodafone router has assigned IPv6 addresses to every device on my network that can handle one. Any device with IPv6 address has now got a IPv6 DNS ahead of mine.  This has taken away my control of my network. If a device is served an IPv6 addess by the IPv6 DNS server then all traffic for that remote IPv6 site is routed via my Vodafone Router. Even if my IPv4 DHCP service has directed that device to use my Virgin Router as a gateway. Messy. 

So, my question:    
I accept that I'm going to have to migrate my DHCP/DNS server for IPv6 at some point but I don't know enough about IPv6 to take that on right now.  What I need right now is to disable IPv6 or at least IPv6 DHCP/DNS on my Vodafone router. Trouble is, I don't seem to be able to find that option, even in expert mode.
Any suggestions anyone?

Thanks in advance,

Graeme

[__graeme]

Thanks @HappyNomad,

When I've got some spare time I'll call support and see it there is any chance of getting the newer one. ATM there seems to be no way to fully turn off IPv6 on the HHG2500 without just unplugging it of course! 

[__graeme]

Update:

I spoke to Support earlier today and they have ordered me a new router. Should be here in 3-5 Days apparently.

Let's just hope it's the right one. 

Interestingly, during the conversation, they told me that IPv6 is only available on Gigafast. I'm not on Gigafast but I definitely have IPv6. After some ums and ahs they realised it seems that IPv6 *is* actually rolling out to everyone.  lol.

Graeme.

[Anonymous]

IPv6 has been leaking onto Vodafone's network for the past several months.  It'd be fine if it was either on or off.  But the problems happen when it comes up, you've devices that come online, see it, and start using it, and then it disappears!  You can then end up with devices that ignore your set DNS servers (from Amazon, Apple, and Google - sound familiar) spamming various services such as NTP which either crash themselves or in some cases bring the entire network down or at least slow it to a crawl.

[__graeme]

Thanks @KeithAlger,

Yes, I had lots of issues over the past couple of days but now, thankfully, my network is mostly back to normal. I had to turn off my VF Router and let all my devices renew their leases or at least forget the IPv6 routing. Annoyingly when the VF IPv6 router advertised itself to my network, it stuck its DNS server above my IPv4 DNS. The effect was that my windows machines and some of my other devices then ignored my DNS set domain name suffix and used VFs IPv6 supplied "broadband" suffix and stopped talking to each other. Sigh.

I suspect that the reason for the inconsistent IPv6 leaks is that some segments have been IPv6'ed and others not. When the VF router gets a new WAN IP it's probably just random whether it gets a IPv6 capable segment (or not).  

[__graeme]

Always good to end a thread on a high.

Vodafone said the new router (yes it's a THG3000) would arrive in 3 to 5 days. In fact it arrived this morning less than 24 hours after my call to support.

The router is in and configured with IPv6 turned off.  It's all working smoothly.

A massive thanks to Vodafone for sorting this out so quick 

[mrwhitey]

Resurrecting this thread...

I have the same issue, but with a brand new router connected to gigafast broadband. The router is advertising its IPv6 address as a DNS server, I disabled IPv6 in the settings and rebooted, but I still see the IPv6 DNS server on my Windows box even after I renew any lease.

Does the IPV6 settings actually disabled the advertisement of IPV6 DNS? Sure I can disable IPV6 on my Windows device, but I can't do this on every device.

[CrimsonLiar]

So far as I'm aware all that is available from Vodafone at the moment is the Teredo service, which acts as an intermediary allowing you access IPv6 sites over IPv4 if needed (and probably only works if you are using VFs own DNS servers).  The Teredo settings are not accessible or published anywhere as far as I'm aware, and so this service is not available to those of us using our own routers.

You can disable the IPv6 service on your windows device in the network protocols, but MS have set this up such that it'll not cause any problems if you don't.

I wouldn't worry about the IPv6 DNS server, the protocols are robust and should in no way affect the ability or speed of obtaining IPv4 addresses!

*I use IPv6 tunnelling via TunnelBroker/Hurricane Electric, while there was a blip on Tuesday of this week, it appeared to be with that tunnelled connection and had nothing to do with any VF IPv6 rollout over FTTC that I can see.

[Cynric]

.@mrwhitey I am assuming that you are not using IP6 on your LAN as you are happy to turn it off in the router. Given that, have you disabled IP6 on the Windows computers (Control Panel -> Network and Sharing Centre ->  Change Adapter Settings -> right-click the adapter -> Properties -> untick Internet Protocol Version 6).

[unmesh90vaidya]

It may work by disabling on computer but my main focus is to connect TV and Android smartphone so without disabling it, i am not able to connect to dns server. 

[CrimsonLiar]

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@unmesh90vaidya wrote:

It may work by disabling on computer but my main focus is to connect TV and Android smartphone so without disabling it, i am not able to connect to dns server. 

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I could make some guesses about the issues, but what exactly is going wrong?  It shouldn't be DNS because if the German servers are set up the same as the UK (yes VF-UK DNS already provides IPv6 addresses when requested), then they would be perfectly able to supply both IPv6 and IPv4 addresses from the IPv4 DNS servers.

*We get users moaning about poor Geolocation - just wait till IPv6 hits, and the hot mess it's geolocation provides.