How to Check Open Ports on a Computer
by Jonathan LangdonThe Internet hosts an ocean of information and entertainment. Surfing those waters can be hazardous to your privacy if your computer is not secure. Identity theft, losing control and malicious software await computers unprepared to ward off security breaches. A sure way of testing the security of your computer is by investigating the state of your transmission control protocol (TCP) ports that handle transmissions ebbing and flowing for your computer. The Gibson Research Corporation provides a free security check online that will let you know if your ports are open to attack.
Visit grc.com. The website belongs to the Gibson Research Corporation, which specializes in security, data recovery and online privacy. Navigation through the website is done through tabs located in the top-left part of the website.
Move your cursor over Services and click "ShieldsUp!!"
Read the content displayed on the new page. The home page for ShieldsUp!! is filled with text explaining exactly how it will test your computer and assurances that the Gibson Research Corporation will not take advantage of the access granted for the test. The page also recommends other services provided by the Gibson Research Corporation.
Click "Proceed" to open the main ShieldsUp!! information page and service launch. There is a lot more text to read here explaining how your computer is vulnerable over the Internet. Read through the sections you are interested in and check out the help links for more information.
Click "Common Ports" when you are ready. ShieldsUp!! will test ports frequently probed by malicious software seeking to gain a foothold into your computer. The test results will explain your computer's stealth capability. If the test cannot detect any ports, open or closed, then your computer is near invisible online. The test summary will list the ports tested along with what programs and services had accessed those ports in less secure computers.
Scroll down to the Shields Up!! Services panel and click "All Service Ports." ShieldsUp!! will test the first 1,056 TCP ports of your computer. As explained in the section "Why the first 1056 Ports?" the ports tested in All Service Ports are designated to incoming connections. The first 1,056 ports of a computer are fertile ground for online interception and should be in stealth mode to bolster security. The results will display a set of blocks in groups of 32, representing the first 1,056 ports of your computer.
Scroll down to the bottom of the page and click "User Specified Custom Port Probe." The new page will explain how to use the field in the center of the ShieldsUp!! Services panel to test ports on your computer in groups of 64. Type in the range of ports and click "User Specified Custom Port Probe" again to have ShieldsUp!! test those ports. To test ports 1 through 64, you would type "1-64" into the field. Through ShieldsUp!!, you will eventually discover which of your ports are open to malicious intent over the Internet.
Tip
- check The Gibson Research Corporation offers a slew of free tools for securing your PC and improving operation. The ShieldsUp!! results are also made available in text format for documentation. ShieldsUp!! also allows you to focus on a single port and learn all about how it is used. If you are ever lost, the ShieldsUp!! pages provide plenty of information and help.
Warning
- close ShieldsUp!! reveals secure information that you may not want others to see. Your computer has over 65,000 TCP ports; it would take a long time to test them all.
