About 2 years ago I was in the works to change the external IP of one of our customers and they had quite some 3rd party VPN's (s2s) with other vendor equipment. To arrange a big bang change when you have 5 or more 3rd parties involved located all over the world, you know this will be impossible to achieve. What we came up with was a 2 month period in which we moved all the 3rd parties one by one.
How? Well quite simple actually. first setting to change is the link selection Source IP address setting, (in R77.30 it was also possible to setup the outgoing interface) to Manual and set it to IP Address of chosen interface.
In the OS routing table the default route is either of the 2 ISP's. In our case we direct those IP's of the remote site's to the correct interface, this way the traffic will go out the right interface and use the IP of that ISP. The other side will also use that specific IP to build the tunnel.
Hi, I am currently in a same kind of situation and wanted to make sure I understood correctly. Ipsec VPN | Link selection page shows first IP Selection by Remote Peer. Should that be Calculate IP based on network topology? All others seem to be impossible solutions, when s2s connections would arrive in two interfaces.
Check Point manual recommends route based probing when using multiple ISP's for s2s's, but did you use just the OS routing table + source ip address setting of "IP address of chosen interface"?