Re: ssh -L syntax question

grandsatrap wrote:
> What is the difference between ssh -L 2000:localhost:5900 frank@server.me.org
>   
This one will forward local connections to port 2000, by connecting them 
to 127.0.0.1:5900 from server.me.org
> and 
> ssh -L 2000:server.me.org:5900 frank@server.me.org ?
>   
This one will forward local connections to port 2000, by connecting to 
the IP address that "server.me.org" resolves to, at port 5900 from 
server.me.org.

I am not sure, but I think that the lookup is done from server.me.org, 
rather than your "local" machine. It will probably look in /etc/hosts 
first, and then ask via DNS.

The distinction here is important, as 127.0.0.1 is (almost) always 
assigned to the lo0 interface, whereas the IP returned from resolving 
"server.me.org" will most likely be assigned to the same network 
interface that you are connecting on. So, for instance, you could set 
your VNC server to only listen for incoming connections on port 
127.0.0.1, for a more "secure" approach using ssh in this fashion. 
Otherwise, you have to make sure that your firewall blocks incoming on 
port 5900.

--
Coleman