Tunnel

Tunnel

This tool comes with a TCP/UDP runnel for the cases when an HTTP proxy is not applicable. In the meantime a network capture tool is implemented, this tunnel is an alternate tool you can use to track and debug the communications.

Features

• TCP and UDP protocol (only one protocol at a time)
• Proxy settings: you can tunnel through an HTTP proxy ;) Applies to TCP tunneling only.
• The client input and the server replies can be shown in hexadecimal format
• Colorized traces
• You can do some tuning in the preferences: define the tunnel queue size for TCP tunneling and the max number of incoming connections for UDP tunneling (see details below).

What this tool does not do

• The proxy authentication is BASIC authentication only
• The tunnel cannot connect to the proxy with SSL
• Direct save of the captured traces

Usage

It is as easy as it could be. First define the listen port of the tunnel, possibly the listen interface. Then define the target: hostname and port, and press "Start Tunnel".

If you want to tunnel through an HTTP proxy, expand the section "Proxy Settings" and check the box "Tunnel through HTTP proxy". Then provide the hostname and port of the proxy. You may provide a login and a password if BASIC authentication is required for the proxy. Finally, press "Start Tunnel".

Few words about UDP tunneling

This feature presents some restriction. By design, there is no way to know if a UDP communication is terminated. This makes the design of a UDP tunnel a bit tricky. To allow parallel processing incoming connections are threaded; so if there is no way to know when a communication has ended, how can we know that we can stop the thread? It is not conceivable to have an infinite number of threads running so for memory preservation sake, I decided to limit the number of running thread: once this limit has been reached, the tunnel stops.