In this scenario, thecorporate networkand thenew remote office networkneed to communicate over theInternet, which requires asecure and dynamic routing method. Since both networks are usingOSPF (Open Shortest Path First)as the routing protocol, the best approach is to establish anOSPF over IPsec VPNto ensure secure and dynamic route propagation.

OSPF is already running on the corporate network, and extending it over an IPsec tunnel allows dynamic route exchange between the corporate FortiGate and the remote office FortiGate.IPsec provides encryptionfor traffic over the Internet, ensuring secure communication.OSPF over IPsec eliminates the need for manual static routes, allowing automatic route updates if networks change.

The new remote office's192.168.1.0/24 subnetwill be advertised dynamically to the corporate network without additional configuration.