I just changed my DSL modem firewall settings from allowing ALL ports from WAN to LAN to blocking ALL ports from WAN to LAN. That breaks IKEv2 VPN connection as expected. I have to change modem firewall settings back to allow ALL from WAN to LAN. Trying to block all and only allow needed ports for IKEv2 VPN connection.
What TCP/UDP ports are needed to allow incoming IKEv2 VPN connection to M270?