Myself and two other engineers used 2910's to vpn to a 2820 for a couple of years all on 20mb virgin and the 2820 on NTL business 10MB static IP, now here's the problem myself and another engineer upgraded to 50mb virgin in March 2009 had to buy 2 x 2930's to utilise full bandwith of 50mb line, setup up VPN no problem. As of end of February begining of March 2010 VPN suddenly does not work anymore, thought that routers were faulty, both of them are on different firmware had all the usual checks done draytek premium telephone support says 2930 dialing out fine, NTL business checks out fine, Virgin residential well thats another story but essentialy cannot VPN or ping or connect to the web interface of 2820 from either of the 50mb Virgin using the 2930's or from the 2820 to the 2930's, by the way the engineer that is still using 20mb virgin and 2910 is still ok. I have taken out one of the 2930's and put in place a 2910 to test and hey presto all is working fine, except now cannot utilise the full bandwith of my 50mb line, obviously virgin have changed something with the service that has caused compatability issues with the 2930, but they will not say what as I can get the 2 x 2930's to talk to each other but not to the 2820, anybody got any clues or any help would be greatly appreciated.

Just one thought, when you've put in the 2930's have you set the LAN subnets to what they were with the old 2910's or did you leave them as default?

I just left them as default

The subnets at either end of the VPN need to be different or it won't work. Find out what they were on the 2910's and copy the settings across. They will (must) be different for both 2930's. If you don't set them as they were in the 2910's, you'll also have to change the VPN configs in the 2820.

yes ok but why have they worked for 12 months March 2009 - March 2010 and now do not work anymore, and the subnets are set to the same as the 2910's but that should not affect me being able to log onto the web interface or being able to ping the 2820 should it?

I misread your first post and thought that you could not communicate over the VPN at the same time as you you installed the 2930's.

FWIW, I am surprised it ever worked if all the LAN's are on the same subnet unless your routers support VPN bridging. My 2900's dont and I don't think the the 2910's do.