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

[prodigualson]

In my opinion, the best way forward would be to use your own router and put the VF router in modem mode. 

[__graeme]

@prodigualson,

My VF modem/router doesn't have Modem Mode. It is a case of plugging in my own router between the VF router and my network and setting my router up as the DMZ device.  
Or is it that I have an old router that lacks "Modem Mode" and "Local Network" (see other reply).

Or maybe I'm needing a firmware update?

[HappyNomad · Accepted solution]

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@__graeme wrote:

@prodigualson,

My VF modem/router doesn't have Modem Mode. It is a case of plugging in my own router between the VF router and my network and setting my router up as the DMZ device.  
Or is it that I have an old router that lacks "Modem Mode" and "Local Network" (see other reply).

Or maybe I'm needing a firmware update?

---

Your Vodafone modem has neither a modem only nor a router only mode but I seem to recall an option to switch IPv6 off.  That said though, since I last used my VF supplied THG3000G Modem/Router there has been a firmware update that reportedly made at least one change to user selectable options.

I will fire my modem up and have a look. 

Edited to add...  I have looked and:

Look under [Expert]/[Settings]/[Local Network] if it is still possible to do and towards the bottom of the page there is an IPv6  toggle switch for both the primary and guest networks.  See beside my jumbo red arrow in the following screenshot:

[__graeme]

Thanks @prodigualson,

Hmm.  It does seem like my menu options are different to yours.

I'm on firmware 5.4.8.1.291.1.30.1.32.1.37.1.1 I'm just checking to see if there is an update.  . . 

 . . There was no update, I'm on the latest firmware.  Maybe they have removed the option to turn off IPv6 ?

I suspect my VF router updated at 02:20'ish this morning. I saw this on my dnsmasq (DHCP/DNS) server:

Mar 9 02:20:18 hs11 dhcpcd[434]: eth0: Router Advertisement from fe80::666d:6cff:feb1:7d10

Mar 9 02:20:18 hs11 dhcpcd[434]: eth0: adding address fd52:a81c:xxxxxxxxxxxxxxxxxx
Mar 9 02:20:18 hs11 dhcpcd[434]: eth0: adding route to fd52:a81c:xxxxxxxxxx/64
Mar 9 02:20:18 hs11 dhcpcd[434]: eth0: requesting DHCPv6 information

So it's possible my DHCP/DNS server is now also implicated .  lol. 

I can't find a way to disable IPv6 in dnsmasq 😧  

[__graeme]

I'm new to this forum, does every image upload have to be vetted before it can be seen?

Are links allowed? 

Expert Mode Menu  

[Alex882]

Your screenshot and firmware version suggest you have a different router from the one that many users have, which is the THG3000. I have no idea how you might turn off IPv6 on yours. As an aside, IPv6 address assignment is often done by router advertisement which is separate from DHCP.

[__graeme]

Lol, our replies crossed in the ether. 

[__graeme]

I just nipped out into the garage to see what modem-router I have (It's all in one).

The About page it says it's a Huawei 963168_HUAWEIVOX25

On the Router it says it's a HHG2500 

Here on the forums a lot of people seem to say it rhymes with wrap  

It certainly has a lower connection speed than my previous Openreach / BT Hub setup. But, as it's only my backup ISP I'm not bothered as it's a lot cheaper than BT.  

[HappyNomad]

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@__graeme wrote:

I just nipped out into the garage to see what modem-router I have (It's all in one).

The About page it says it's a Huawei 963168_HUAWEIVOX25

On the Router it says it's a HHG2500 

Here on the forums a lot of people seem to say it rhymes with wrap  

It certainly has a lower connection speed than my previous Openreach / BT Hub setup. But, as it's only my backup ISP I'm not bothered as it's a lot cheaper than BT.  

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Thats the older router... the current device is the THG3000G