Thank you for your reply!
So is there a possibility at all to have an IPSec Tunnel handle a failover from DSL to UMTS in pfSense?
At the moment it seems to me that you need two tunnels anyways, one for the DSL connection and one for the UMTS connection, but they would both need to terminate on the datacenter pfSense.
But then, as soon as two tunnels are supposed to terminate on the same remote wan IP, it won't work, no?
So it would be necessary to have at least two WAN ips on the datacenter pfSense? ???
Isn't there a more elegant solution to handle a WAN failover in the office site - including the IPSec VPN that also can follow the failover?
Thanks!