Fortigate Unnumbered IP against PPPoE Interface
I ran into some very strange behaviour on a BT Business Fiber connection with PPPoE and static IPs assigned by the ISP on a Fortigate firewall. A site-to-site IPSec VPN was required, however the tunnel kept terminating as BT assign a dynamic address with the PPPoE connection, then the static IPs are typically ingested through the use of Virtual-IPs on the fortigate unit, however IPSec requires the use of the router WAN address and it needs to be static....