Tunnelling UDP Traffic Through An SSH Connection

Overview

This section describes how to use NST to tunnel a UDP traffic conversation through a SSH connection. For our example we will tunnel IPMItool traffic (UDP Port: 623) through an SSH connection to a Sun Fire X4200 server. Three systems are involved, 2 NST probes and the x4200 server. Reference information was taken from: "Performing UDP tunneling through an SSH connection".

Tunnel A TCP Forward Port Through SSH

First we need to tunnel a "non-used" TCP port from the local NST probe to the remote NST probe which shares the same LAN as the destination x4200 server.

Establish SSH Connection With TCP Port Forwarding

[root@probe tmp]# ssh -p 31222 -L 9999:localhost:9999 root@55.44.22.178

root@55.44.22.178's password:
Last login: Thu Mar 22 11:18:59 2007 from cpe-72-222-76-188.nycaper.res.rdr.com

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= Linux Network Security Toolkit (NST v1.5.0) =
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[root@probe-biostar ~]#

In this example SSH is being NATed through a firewall. The SSH listening port is: "31222". We have choosen to use TCP port forward the "non-used" TCP port: "9999". The remote NST probe's IP address is: "55.44.22.178".