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's Integrated Lights Out Manager (ILOM) service processor network interface. Three systems are involved, 2 NST probes and the X4200 server. Reference information was taken from: "Performing UDP tunneling through an SSH connection".
Step By Step:
Tunnel A TCP Forward Port Through SSH
First we need to establish the tunnel for a "non-used" TCP port from the local NST probe to the remote NST probe SSH server which shares the same LAN as the destination X4200 server.
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 =============================================== = Linux Network Security Toolkit (NST v1.5.0) = ===============================================
In this example SSH traffic is being NATed through a firewall. The SSH filtered port at the dirty side of the firewall is: "31222". We have chosen to use TCP port forwarding for the "non-used" TCP port: "9999". The remote NST probe's IP Address is: "55.44.22.178". On the local NST probe, TCP port: "9999" is bound to the localhost IP Address: "127.0.0.1".
Use: "nc" To Translate TCP To UDP Forward On The SSH Server Side
On the remote NST probe (SSH server side), we need to open a TCP port listener on the TCP port: "9999" which will forward all network traffic to UDP port: "623" for the IP Address assigned to the X4200 server's ILOM network interface.
We will first need to create a "fifo". The "fifo" will be necessary to maintain a two-way communication between the TCP port listener and the UDP port. A simple shell pipe would NOT work. It would only communicate left process' standard output to right process' standard input.
