For information exchange in network the transport protocol of TCP establishes connection between the applications working on computers. The address field of each data packet includes the numerical identifier which specifies what application will process information. These numerical identifiers are called network ports. They are numbered in the range from 1 to 65535.
Instruction
1. Learn what applications and processes occupy ports of your computer, it is possible means of Windows. Start the command line from the Start menu and enter cmd. In a window of the console gather netstat – a – n – o
The command displays the list of all active connections of TCP and UPD, ports and processes. In the Local Address column the IP address of your computer and, through a colon, the port number, occupied with process of the PID column is specified. "Foreign address" reports the address of a remote node and port which are listened by the corresponding application.
2. To recognize a process name by its number, open with a combination of the Ctrl+Alt+Delete keys a window of "Process manager". Press the Task manager button and select the Processes tab. To each number in the PID column there corresponds the name of process or the application in the Name of an Image column.
If in a window of "Task manager" PID are not displayed, in the main menu choose the View and Select Columns commands. Note a checkbox point "Identif. process (PID)".
3. That check availability of any port, enter into the command line of cmd. In a window of the console gather telnet. The next line the invitation to work with this command will appear. Gather open where domen_name – a name of your domain, port_number – the port number.
If the port is closed, the message about failure will appear: "It was not succeeded to open connection to this node, connection failure". If the command enters a dialog and issues significant information – the port is open.
4. Protect ports of the computer from unauthorized actions of the program firewalls, or firewalls. Sometimes happens it is necessary to open some port for communication with other node. If you activated the built-in firewall of Windows, via "Control panel" come into the section "Network Connections". Click the right mouse button on the icon of connection to the Internet for a call of a context menu. Choose the Properties command, select In the addition tab and click "Parameters".
5. In the Brandmauyer of Windows window click "Add Port". In the Name field enter the description of the application which will occupy port, in the field "Port Number" – any number. If your version offers the TCP and UPD protocols at choice, carry out the procedure twice. If you add port for work with a certain application, click "Add the Program" and specify network path to it, having clicked "Overview" or "Change area".