The specific ports that need to be forwarded for a VPN connection depend on the VPN protocol being used.  Here are the commonly used VPN protocols and the corresponding ports they typically require for forwarding: PPTP (Point-to-Point Tunneling Protocol): TCP port 1723. L2TP/IPSec (Layer 2 Tunneling Protocol/Internet Protocol Security): UDP ports 500, 1701, and 4500. SSTP (Secure Socket Tunneling Protocol): TCP port 443. OpenVPN (UDP or TCP): UDP port 1194 or  TCP port 443 or the custom port specified in the OpenVPN server configuration file if it has been changed to a different port. Some VPN providers may use non-standard or custom ports for their services.  In such cases, you should refer to the documentation or support resources provided by your  VPN service to determine the required ports for forwarding. Additionally, if you are behind a router or firewall, you need to forward these ports on the respective device to allow incoming VPN traffic to reach your VPN server or client.