[來源]:http://www.techontour.com/networking/2007/11/03/ports-needed-for-vpn-passthrough/
Ports Needed for PPTP VPN
- TCP Port 1723
- UDP Port 500
Ports Needed for L2TP VPN
- TCP Port 1701
- UDP Port 500
Ports Needed for IPSec/ESP
- UDP Port 500
