To see what ports are open on your computer, run the shell by selecting "start – All programs – accessories – Command prompt" and type the command netstat –aon. Press Enter. You will see a list of connections. In the column "Local address" next to the listed addresses and numbers of ports.
You can find out which program is using the port you are interested in. Note the last column – PID. It shows the process IDs of the processes, with their help, you can find out which program opens a particular port. This can be done in two ways.
Open task Manager (Ctrl + Alt + Del), under "View" click "Select columns". Check the box in the "process ID". In the task Manager window will appear in the column PID. Now you can see in the command prompt window, the process ID of the application using interesting port and the task ID to determine the name of the application process. If the name itself tells you nothing, type it into a search engine and you will get all the information on this process and the appropriate program.
You can get the same information by typing the same in the command line command tasklist. Displays a list of processes with their identifiers. Then everything is exactly the same as in the previous step, map the port identifier and the name of the process to obtain the information you need.
Sometimes you need to determine numbers of open ports on a remote computer. For this purpose, special programs that scan ports on the computer and determine which of them are open. One of the best programs of this kind is scanner Nmap. Exists as its console version and the familiar Windows user interface window.
Very strong research and development complex is to program Metasploit Framework, its composition is and Nmap. To check a remote computer, you can use the program XSpider. The same program you can check and safety of your own computer – enter the address of and run the scan. The program will show not only the open ports, and existing vulnerabilities.