Determining the External IP Address

http://support.steampowered.com/cgi-bin/steampowered.cfg/php/enduser/std_adp.php?p_faqid=192

If you have a modem or a router that uses NAT translation and DHCP then your computer may have a different internal IP address then your real external (ISP provided) IP address.

If you have what is called a "Dynamic IP" then your external IP address will change from time to time. If you have a "Static IP" address then your external IP address will stay the same all the time (usually much better if you want to run a game, web or FTP server).

Please see the Steam Support FAQ linked below for assistance in determining your external IP:

http://support.steampowered.com/cgi-bin/steampowered.cfg/php/enduser/std_adp.php?p_faqid=192