Wireguard VPN inaccessible from WAN

[Exor]

Hello everyone,

I made a Wireguard VPN server in Proxmox with no internal firewall. Our firewall is Cisco Firepower 1120 which manages all the aspects.

I have tested connecting to VPN server from within LAN and it worked but no internet access, I added iptables and now it's working. So, I know VPN server is working. I am still not able to connect to the VPN server from outside of LAN. Wireguard is not able to handshake with the server.

This might be ip/port forwarding issue. I may be missing something. I have the following set up already below. Let me know if I am missing something? Any help is appreciated!

[Aref Alsouqi]

What that VPN port is? Did you make sure that the firewall itself is not running any VPN services on the same port? Not sure if the firewall would return any error in that case when you try to configure the NAT rule.

[Exor]

VPN port is 51820. Firepower is not running any VPN services; we do not have license for it which is why I am testing Wireguard VPN server instead. I can confirm there is no duplicate port being used in Firepower's ports list.