I will be grateful for any advice given sice I am not very proficient with this issue. Looked for such a topic but couldn't find one. I have the following scenario: head office on Vigor 2860 and two branch offices both on Vigor 2866. Currently there are VPN connections between each branch and head office using IPSec encryption. The setting works. However, I want now to link the two branches together using a VPN in case there is a glitch with the head office connection. I was unable to make VPN IPSec work when one branch is dial-in and the other dial-out. Can you advise if the is possible and what should I do. Thanks for the time given to this request.

try with a basic pptp vpn between the sites but set it so it only gets used when the main vpn goes off.

Thanks Phill, just to clarify, your recommandation is to use intermitent PPTP and not encrypted IPSec and more importantly the connection to be trigerred ONLY when needed. My question is if there is a way to use IPSec with a permanent connection of DialIN permanent connection? Would this be possible. Have tried and does not connect whilst the permanent connection is working between branches and main office. Can you elaborate on this plese?

This is what drayteks own troubleshooter says.

if you dont want to try pptp then please try one you prefer.

Let us know how you get on.

PPTP is simpler to set up as a protocol than IPSec. If you are troubleshooting, we therefore recommend you start with PPTP and confirm that the basic connection and settings work. You can then switch to IPSec or other protocols later, once the basic concepts and connection have been tested.

https://www.draytek.co.uk/support/guides/kb-l2l-vpn-troubleshooting

I know this might not be helpful but you might want to just experiment i am stuck on something myself and i am trying to work that out.

Have you tried Aggressive mode.
https://www.draytek.co.uk/support/guides/kb-lantolan-ipsec

Have you set the local ID in the advanced tab