> is it possible to use putty and go out in the internet and come back
> about the same interface. so i use the isp ip.
> 
> windows(putty) ---> mono --> dyndns ---> mono ---> linux
> 
> is this possible?

Sorry :-(

But if you just need to test your setup, ask someone outside your LAN to 
connect to your WAN IP address on port 22.

The problem may be with sshd or even your Linux setup preventing foreign 
hosts from establishing a connection. Take a look at sshd logs, too.

-- Vincent