I just bought a new Draytek and have configured it similarly to our old router, however we have been having trouble getting it to work as the previous one. There are two issues, but I will submit separate posts for each one.

The issue we have is we have 3 VPN's configured using IPSEC. These all work fine and are reliable until we enable the IP Routed Subnet under LAN - General Setup. As soon as that is enabled the VPN's are unreliable. One connection doesn't ever connect, whilst the other two will connect they both drop within an hour of connecting. After the initial connection, they will no longer reconnect until the router has been rebooted. As soon as the IP Routed Subnet is disabled the connections all work again without a problem.

The router is using the latest firmware version 3.7.3.2.

Any help would be greatly appreciated.

I think your other post says you have the alias' set up on WAN2 - in that case why would you enable the IP routed subnet if the range is already in use on the WAN2 interface?