Re: SSH Tunnel - How does it works?

This is why SSH is so great ;) If you do:

host3: # ssh user@host1 -L xx:host2:xx

and do on host3: telnet localhost xx you will see that sshd on host1 
will connect to host2:xx and all traffic will be transfer do sshd on 
host3 (encrypted way) and after that sshd on host3 will insert this data 
on port xx (on host3).

PLS remember also that connection between host host1 and host2 is not 
secured by ssh.

Rgds,
nosorozec

Pablo Hauser wrote:

> Hi list,
>        Using SSH Tunneling, I was wondering how does
> it really works in the following scenario:
>
> Host1 running putty with tunneling on port xx, and
> redirecting its traffic to Host2, and Host3 accessing
> host 1 via port xx.
>
>  | Host3    |     |    Host1    |     |   Host2  |
>  | traffic: | --> |SSH tun on xx| --> | receipt: |
>  |(Host1:xx)|     |redir. Host2 |     |(Host1:xx)|
>
> The idea is that Host1 redirects Host3:xx to Host2,
> but the question is: When traffic from Host2 comes
> back to Host1 as a reply of the former packet, how
> does Host1 REALLY knows that the packet must be
> forwarded to the tunnel and not, for example, to its
> Default Gateway?
>
> I think it should add some kind of dynamic route for
> that single connection, or keep some kind of table to
> 'know' that the answer should be lead to the tunnel,
> but those are only suppositions... Maybe any of you
> have the correct answer.
>
> Thanks in advance.
>
> Pablo D. Hauser | pH
> www.securearg.net | Secure from the source
>