"Closed" is the best you can hope for without a stealth firewall or NAT router in place. At least the port is not "Open" for business and accepting connections from the probes, which are continually sweeping the Internet searching for exploitable systems.

  Anyone scanning past your IP address will detect your PC, but "closed" ports will quickly refuse connection attempts. Since it's much faster for a scanner to re-scan a machine that's known to exist, the presence of your machine might be logged for further scrutiny at a later time — for example, when a new operating system vulnerability is discovered and before the potential for exploitation has been repaired.

  For this reason it is important for you to stay current with updates from your operating system vendor since new potential vulnerabilities are discovered frequently.

Stealth port

  A "Stealth" port is one that completely ignores and simply "drops" any incoming packets without telling the sender whether the port is "Open" or "Closed" for business. When all of your system's ports are stealth (and assuming that your personal firewall security system doesn't make the mistake of "counter-probing" the prober), your system will be completely opaque and invisible to the random scans which continually sweep through the Internet.

Even if this machine had previously been scanned and logged by a would-be intruder, a methodical return to this IP address will lead any attacker to believe that your machine is turned off, disconnected, or no longer exists. You couldn't ask for anything better. Your personal firewall or NAT router protected system is acting like a black hole for TCP/IP packets. That's very cool.