Friday, August 12, 2011

How to do an secure tunel with ssh in Linux

You may know that ssh is a secure way to connect, remember those old days when telnet was used and the passwords just flew through the network and any person with a sniffer could capture it ?

With ssh you can create a secure connection from one point to anther, going through a middle point, like the figure shows:
The tunnel is an cyphered connection from A to B, and from B to C the connection is not cyphered (almost not by ssh that we are using). B acts as a gateway to C.
In A you would write:
$ ssh -g -L [port in A]:[C address]:[port in C] [b address]
Example of doing a tunnel to a webpage:
$ ssh -g -L

You would connect with your browser to
This would create a tunnel from A to B and B to gmail, this way nobody in A's network will be able to sniff the gmail traffic, only in B's network would that be possible.