I have a router_A forwarding 500 and 4500 ports to firebox_A because of IKEv2 VPN.
I need add a firebox_B under the same router_A to connect to other internal network. Is that possible? Can we change the IKEv2 default ports?
Q. Can we change the IKEv2 default ports?
Review the "Disable or Enable the Built-in IPSec Policy" section of this.
You would need at least 2 public IP addrs to accomplish this - 1 for IPSec to each firewall.
About Global VPN Settingshttps://www.watchguard.com/help/docs/help-center/en-US/Content/en-US/Fireware/bovpn/manual/global_vpn_settings_about_c.html