MOBIKE settings in Gateway Settings
MOBIKE (mobile IKE) return routablility checks (RRC) can be used with IKEv2 to verify the validity of VPN client or gateway IP addresses if the IP address changes in the middle of an open VPN connection.
The IP address is updated in the negotiated SAs when the new IP address has been verified. If the new IP address cannot be verified, the VPN connection is closed. By default, no return routablility checks are done.