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THG3000 modem mode

2: Seeker
2: Seeker


Have recently had fibre Pro broadband installed with the THG3000 router. 

The WiFi is so bad that I'm looking for alternative routers to provide WiFi. 

Is there a way to set the THG3000 into modem only mode and then use a separate WiFi router?

Have tried a few routers I have around the place but none connect to the ethernet connection from the open rech fibre box.

Thanks for your help




16: Advanced member
16: Advanced member

Are you on FTTP? By Openreach fibre box do you mean the ONT?

If so just about any router will work, but you will need your username and password, get it via live chat:

However you will lose the telephone service.

Thanks for the reply Jayach

It's fibre to the prem terminated in an open reach wall box which converts to an ethernet connection. 

Will that make a difference? 

16: Advanced member
16: Advanced member

No, that box is called the ONT (Optical Network Terminal), so just connect a router with the correct PPPoE username and password and it should work.

16: Advanced member
16: Advanced member

No you cannot put the THG3000 in modem only mode as it doesn't have one.

While you can use your own router, you will loose the landline as you must use the THG3000 to make and receive calls over your Vodafone landline (FTTP).

16: Advanced member
16: Advanced member

There is a function in the vox3 called "Open Host Function" which is the closest you'll get to a pure modem mode.

You need to set up your own router to connect using dhcp, assign a fixed IP to your own router on the vox3. In expert mode go to the Internet settings and then to "Static NAT/DMZ". Enable the "Exposed Host" function, add the static IP of your own router then click apply.

It does work pretty well as a workaround, and you get to keep your digital landline. Additionally you'll also have access to the vox3 through your own router using its IP ( by default) no matter what subnet you're using on your own router/network. 

Don't forget each router will need it's own subnet.


Hi Ripshod,. it seems your reply went completely unappreciated, but I tried it and after some battling with the DHCP wars between the two routers, I finally got it working how you said!!

Which, I wish I'd have managed to do before I ordered a separate modem + VOIP gateway, but to be honest, I just want this piece of VF trash off my network now. But as the VOIP gateway (HT812) is coming from Amazon US, this will help me massively in the meantime! Cheers!

And for anyone else wanting to do use the VF router as a modem/bridge, follow what Ripshod says, but you need to make the VF router recognise your permanent router so that you can then give it a static IP in Settings > Local Network > Static DHCPv4

Once you've assigned an IP to your perma router here, you can then go to Internet > Static NAT/DMZ and add the chosen IP to the firewall exclusion. It doesn't even matter if your perma router is on a different subnet (in its own settings). My perma router runs on 192.168.2.x, but inside the VF setup, you have to give it a dummy IP which is on the VF subnet (I chose This subnet variation between the two routers won't affect anything as long as you then connect an ethernet cable from the VF LAN to the perma routers WAN. Reboot both, and you should then have live WAN after 2-5 mins. Also don't disable DHCP on the VF router. It will just disappear from the network. You don't need to disable the VF's DHCP for this trick to work. 

Sorry to revive an old thread but struggling with the same issue. I've followed these instructions and it's working well, except... I have a double NAT issue. My new router (Asus) thinks its WAN IP is a 192.168.1.x address, and tracert shows devices connected to the Asus router as connecting via both the Asus router and my Vodafone THG3000.

Is this inevitable? Any tips on what might be going wrong?

16: Advanced member
16: Advanced member


Whichever router is the one on the LAN side should have its WAN port connected to a LAN port of the router that is connected to Vodafone.

The router connected to Vodafone :

has DHCP off
is best left on
has WiFi off
has IPv6 off
don't care about DNS

The LAN side router:

is on
has DNS on and set to and
has DHCP serving to 192.168.254 (unless you want to reserve any static numbers)
has WiFi on
has IPv6 off

Thanks Cynric. I've tried this, and still having some issues.

VF router is set up:

  • DHCP off
  • It's IP
  • Wifi and IPv6 off
  • Static IP assigned to Asus router of in VF setting (assume a typo above where you say
  • Static NAT/DMZ set to on, forwarding to

Asus router set up:

  • Incoming WAN port connected by cable to LAN port of VF
  • DNS on set to and
  • DHCP on, with its own IP as, and range from to (if I try to allocate it it says "WAN and LAN should have different IP address and subnet"
  • Wifi and IPv6 on

In the Asus settings, if internet connection type set to automatic, it then says "Your ISP's DHCP does not function properly". If I set it to connect via a static IP, setting the static IP to and gateway IP to then it works. But, forgive my ignorance, but that still doesn't seem to resolve the double NAT issue. Any help greatly appreciated...!