Previously Virgin Broadband users in the UK on Virgin's cable network were supplied with a standard DOCSIS modem and were required to connect their own (or Virgin supplied) router to allow multiple devices to connect at the same time.
Recently Virgin Broadband have changed what they supply and now use the Super Hub (a custom Netgear router) which is wireless capable and supports multiple devices. However some customers still prefer to use their own router instead of the Super Hub especially when wanting to support multiple Xboxes with an Open NAT which (at time of writing) the Superhub does not support.
If you simply connect your own router to the Superhub will will encounter NAT issues even with one Xbox as you are "double NAT'ing" Virgin have hinted that they will in the future release a firmware update for the Superhub to allow you easily turn off its routing functions and make it a very standard modem so you can connect your own router.
Until this time there is a workaround available so that you can correctly connect your own broadband router to the Superhub wth the Superhub acting as a standard modem and handing off all of the work to your second router.
Plug your cable router’s WAN port into any of the LAN ports on the VMDG280.
Plug your PC into any VMDG280 LAN port and access the management page by entering 192.168.0.1 into your web browser
Login to the VMDG280 the username/password details are on a sticker on the side of your hub (more help here)
On the LAN IP page examine the DHCP lease info; you should see your PC and the second router list.
Note the MAC address of the router and add it to the DHCP reservation section and give the second router an IP address of 192.168.0.10. (Use ipconfig /all in a cmd window to find the MAC address of your PC if your not sure which is which)
Now go to the DMZ host page on the VMDG280 and enter the same IP address (e.g. 192.168.0.10). This means that the VMDG280 will pass all traffic to the second router without any checks or filters
Additional Suggestion:- At this stage it would also be wise to turn off the VMDG280 wireless functionality and firewall and let your second router provide this for you
Turn off the second router and back on again, plug your PC into the second router, login to the second router and set the router’s WAN setup for "Does your Internet connection require a login" to NO, this may also be known as Internet Connection type - "Automatic Configuration - DHCP" (it varies from router to router) and then you should see the WAN or internet as 192.168.0.10
Connect any remaining devices to the second router as the Virgin Hub is now being used as a basic modem only
The changes are now complete
The instructions above will work for the VMDG280 and VMDG480
(currently 20mb)