OpenVPN is a robust and highly flexible tunneling application that uses all of the encryption, authentication, and certification features of the OpenSSL library to securely tunnel IP networks over a single TCP/UDP port.
Discussion forums and project wiki can be found here:
https://forums.openvpn.net/
http://community.openvpn.net/openvpn
Pen is a load balancer for udp and tcp based protocols.
This is Pen, a load balancer for udp and tcp based protocols such as
dns, http or smtp. It allows several servers to appear as one to the
outside and automatically detects servers that are down and distributes
clients among the available servers. This gives high availability and
scalable performance.
irctunnel is a command-line daemon, written in C++, which
allows users to tunnel TCP connections through IRC
server. It makes possible to connect two computers behind NAT, because
actual connection is done through the IRC server.
TDFS-lis can be used both as TCP client and TCPserver with IPv4 and IPv6 support. TDFS-lis is a general pourpose tool, usefull to test clients, servers and services.
Secure File Transfer for Windows with Cerberus by Redwood
Protect and share files over FTP/S, SFTP, HTTPS and SCP with the #1 rated Windows file transfer server.
Cerberus supports unlimited users and connections on a single IP, with built-in encryption, 2FA, and a browser-based web client — all deployable in under 15 minutes with a 25-day free trial.