So I setup a VPN Server for a friend. But what’s a VPN Server if you are unable to access it form the outside world. This is where opening ports on ones router / firewall is required. Rather than focus on a specific firewall vendor or appliance, I will just focus on the ports and protocol required.
L2TP / IPSec
- L2TP traffic – UDP Port 1701
- Internet Key Exchange (IKE) – UDP Port 500
- IPSec Network Address Translation (NAT-T) – UDP Port 4500
- PPTP tunnel maintenance – TCP Port 1723
- GRE – Protocol ID 47