We have a remote office with a 200mbs VMB line and Hitron CGNV4 Router. The Hitron is in modem-only mode and we have a Vigor2862 router behind it so we can run a LAN-to-LAN VPN to head office for server access and IP phones.

At head office we have a 1000mbs fibre leased line and a Vigor3900 router, then we have set up an IPSec VPN between the offices.

We started off with 5 static IPs, however after reading things like this: http://www.thebmwz3.co.uk/2017/05/virgin-media-business-cable-and-static.html and https://www.cableforum.uk/board/showthread.php?t=33702977 and from what the engineer said about supporting VPN we have reverted to a dynamic IP just to make the VPN work.

Since we have experienced consistent issues with the VPN regularly dropping out, sometimes up to every couple of minutes, causing phone calls to drop etc. The maximum speed we get with the VPN active is about 40mbs down and 20mbs up.

Draytek support have logged in and rebuilt the VPN profiles several times, and say that everything is perfectly set up and it must be the virgin connection which is not compatible with the VPN set up.

Virgin telephone support say that it should be working fine and told me to check with Draytek!

Has anyone else experienced a similar situation and how was it resolved?

Does anyone have a definitive answer from Virgin Media regarding using their VMB connection for running a VPN between Draytek/any other third party routers?

Appreciate any comments or advice