Port forwarding is a technique used to enable incoming internet connections to reach your device when using a VPN. It is necessary because most VPNs use an NAT firewall to stop users falling victim to malicious incoming connections. This is a useful security feature, but it is unfortunately unable to distinguish between incoming connections you don’t want and those that you do.

Port Number - What is it & How to Find My Port Number? How To Guide: Set Up & Configure OpenVPN client/server VPN Now you are trying to connect to the VPN from an internet cafe which is using the same subnet for its WiFi LAN. You will have a routing conflict because your machine won’t know if 192.168.0.1 refers to the local WiFi gateway or to the same address on the VPN. What ports does VPN use ? :: SG FAQ

Configure DNS and Firewall Settings | Microsoft Docs

Now you are trying to connect to the VPN from an internet cafe which is using the same subnet for its WiFi LAN. You will have a routing conflict because your machine won’t know if 192.168.0.1 refers to the local WiFi gateway or to the same address on the VPN. What ports does VPN use ? :: SG FAQ

how to check the port status in IPSec VPN - Cisco Community

How to set up VPN server with port forwarding? | Official Apr 24, 2019