Closed port
A port that is blocked by a firewall. If a computer receives incoming communication on a closed port, it responds to the sender by refusing the connection. See also port, open port, port scan, and stealth port
Stealth port
Giving the impression of not existing; not responding to requests for information. A firewall can be configured to "stealth" ports, so that anyone performing a port scan will not be able to determine that a computer exists at that address.
http://service1.symantec.com/SUPPORT/nip.nsf/docid/2002042913273736Pleier riktig nok selv å konfigurere til stealth, men tviler egentlig på at det i praksis medfører den store forskjell.