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Protecting Your Data: A Guide to Windows Firewall


Open Ports


When a server provides an available port, the port is said to be "open." On web servers, port 80 is always an open port. If the program that controls these open ports has a flaw in its programming, hackers can use these vulnerable ports to gain unauthorized access into a computer system. That's why there are constant updates to your Windows XP operating system and the applications that run on your computer.

Your computer probably has open ports right now as part of its normal operation. To see these open ports, open a command prompt by selecting Start, choosing Run, typing "cmd" (without the quotes) and click OK. At the resulting command prompt, type "netstat -a" (again without the quotes) and view the results. Any ports identified as "LISTENING" are open to the outside world.

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C:\Documents and Settings\James Messer>netstat -a

Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    POWER:epmap            POWER:0                LISTENING
  TCP    POWER:microsoft-ds     POWER:0                LISTENING
  TCP    POWER:1029             POWER:0                LISTENING
  TCP    POWER:62514            POWER:0                LISTENING
  TCP    POWER:netbios-ssn      POWER:0                LISTENING

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My computer shows five open TCP ports that are used for Microsoft file sharing and VPN connectivity. Each of these open ports provide a conduit to my computer, and it's important that I keep these applications updated to the latest version to protect against security vulnerabilities.


Update, Update, Update!
Because of these open ports on your computer, it's important to keep your system updated with Windows Update. Check your Control Panel / Security Center / Automatic Updates setting to verify that your Windows XP system is configured to automatically protect your computer!