How does it work????

[ivica.glavocic]

Hi all

Softether VPN Server Ver 4.12, Build 9514 on RHEL6.6 x86, Internet interface with static public IP address, LAN interface with private C class IP, SoftEther server bridged (no SecureNAT) to LAN. Iptables rules allow traffic from server to Internet, from LAN to server and drop everything from Internet to server.

Softether client on Internet -> VPN connection to server - WORKS !!!!

How ??? All Internet ports are closed, double checked with NMAP.

From what I can see, SoftEther server periodically communicates with 130.158.6.114 (University of Tsukuba) - does it report it's capabilities? When connection from Internet client is made, first packets are sent to TCP443, dropped since that port is closed, after that successful connection is established using UDP protocol on high ports between server's and client's Internet IP address.

Before I start using SoftEther in production, I would like to know how it works and what ports/protocols to opet to have VPN server on secure and protected network. I would also like to have functional server which does not depend on external resources such as University of Tsukuba IP 130.158.6.114, if possible. Where can I find such information?

Thanks, regards,
Ivica

[thisjun]

Please google UDP hole punching.