Question : Problem: Problem with ssh connection from Linux to XP

Hello experts,
I'm having some problems connection to my home computer (Win XP) using my Ubuntu 8.04 laptop.

I can make the connection when I'm at home where I don't have to deal with my 'outside' ip-address but only the router given ones. I installed Cygwin on the Windows machine so please ask me anything about that if you need to know. I'm using Putty on the Linux machine, and like I said it works perfectly when at home. But when I try to use it anywhere else using the hostname
computername@outside-ip-address
I get a 'Unable to open connection to computername@outside-ip-address: Name or service not known'

Please note that I am a beginner so if you could post questions like 'Do you have xxxx setup ? You can see it by doing yyyy' that would be great.

Thanks

Answer : Problem: Problem with ssh connection from Linux to XP

Here is some good information from this webpage:

http://pigtail.net/LRP/printsrv/cygwin-sshd.html

Users from the outside (geeks call this a WAN) can
 ssh  username@external_ip_address   (e.g. ssh   [email protected] )

Caveat Emptor   :
-assuming you have an IP address that is accessible by the outside world, some  ISP do not give out outside-accessible IP address.    <-- You are good here
-assuming your ISP does not suffer from extreme paranoia, he/she allows "port 22  TCP" traffic through their network.                                      <-- ???
-assuming your firewall allows TCP port 22 and port forwards to the  computer running the ssh server.                                                                  <-- You are good here

If you want to use TCP port 443 as the sshd listening port   (instead of the  default SSH port 22), see this page: http://pigtail.net/LRP/printsrv/port443.html

(Why? Port 443 is normally assigned to https traffic, even severely paranoia IT geeks will leave this port open. Some IT geeks will even intercept TCP port 443 traffic and redirect them to a proxy server, these are the extreme total control freaks).