I have a fedora core 6 machine that I use as a server. I am on a windows machine on the same network and simply use putty to ssh to the linux box. Everything works fine for me while I am on the windows machine, but if I try to ssh from a computer not on the network I can't connect. I have a domain name registered with Dyndns and have my dmz enabled and on the right ip. I checked to make sure that the linux box was accepting on port 22. I even opened all the ports on my router to the linux box and I still can't connect with ssh. Any suggestions?

Can you connect by IP? And go ahead and close all those ports except 22, that's just a bad idea and pointless..

I'd try pinging your IP. I know some ISP's block certain ports so you cant get to it. So you may have to end up using a different port to connect to you linux box. That's what I do. I added Ports 1822 to my /etc/ssh/sshd_config file

Maybe your dsl/cable modem is blocking the port, not your router. Some modems have ip passthrough option. If your protocol is supported by your router, then you can set your modem in bridge mode and let the router authenticate....(pppoe,pppoa,....). Also, are you sure you are using the correct ip? Go to checkip.dyndns.org from your linux box and make sure.

I tried to connect by ip and still have had no success. Also I only open the ports for a few minutes while a friend tried to connect.