Problem

Virgin Media super hubs often have an issue where they block VoIP traffic. This is due simply to the default Firewall settings on the router itself; most phones will connect to their PBX or SIP gateway however some phones more frequently than others will de-register such as Ciscos and Snoms.

Solution

The solution to this issue is to disable some default features on the Firewall to allow the connections through, note this also applies to VPNs on a Virgin media network.

You will need to enable IPSec 'Pas-Tthrough', 'PPTP Pass-Through' and 'Multicast Pass-Through' on your Virgin Superhub.

1. Browse to your SuperHub's IP Address (e.g. 192.168.0.1) and log in
2. Select 'Advanced Settings' and click 'Yes' to confirm you want to view these
3. Select 'Firewall' from the list
4. Tick 'IPSec Pas-Tthrough', 'PPTP Pass-Through' and 'Multicast Pass-Through' at the bottom of the page
5. Click 'Yes' to confirm settings change

Once complete this should resolve the issue for intermittent connections.