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

  • PPTP tunnel maintenance – TCP Port 1723
  • GRE – Protocol ID 47