I'm trying to set up an IPsec Tunnel VPN from a remote office to our main office using a Vigor 2820 in the remote office (behind another router as it's a serviced office) dialling out to our main office and connecting to a Vigor 2862. I have set it up as per the instructions on the Draytek web-site and can get it to connect as required. For some reason, though, it will only connect for about 8 seconds before it disconnects and then reconnects again, it just won't give a stable connection. I have checked the WAN it is connected through and that is stable.

Bizarrely, after giving up on it I disabled the vpn profile but must have done it whilst the vpn was within the 8 second window of being connected, and it has remained connected since. This makes me think that the vpn profile must be continually re-dialling but I am at a loss as to why?