What is a Port?

A port is a way for computers to communicate over a network. In order for a computer to connect to the internet to communicate with other computers the transmission standard TCP/IP was created. TCP/IP short for Transmission Control Protocol/Internet Protocol is a host of communication protocols. One of the most attractive features of the of TCP/IP is that it doesn’t depend on the computer’s operating system, making communication between two operating systems possible. An TCP/IP is used to connect hosts on the internet, it also transport data over a network, like email on the internet

Every computer with internet access has an IP address. An IP address is similar to a street address in that it identifies where your located at. An IP address is an identifier for a computer on an TCP/IP address. IP addresses come in the form of telephone numbers. In an IP address there are four numbers per block and those numbers can only contain a value from 0 to 255.

By knowing the IP address of a computer you know where to exactly send information to a another computer. What about the computer that receives the information, how will they know what program to use to for the information it receives? Well, that’s why port numbers exist. Every time data is transmitted, it must be enclosed with the IP address and the port number which the program is responsible for.

It’s much easier to think of a port number as a telephone number. Just like you can be contacted by a certain number such as (862-555-0982), when a computer has a port number you can make contact with that computer. A port number is similar to a telephone number in another way. If you try to call a specific person by dialing their number but the operator either says the number doesn’t exist or is disconnected, the same thing can happen with a port number. If you try to connect with a computer through a port number and it has no service, the connection will not go through. Simply a port number is a way to identify a certain process to which the Internet or another kind of network message is being forwarded too when it reaches the server.

Port numbers can vary, they can be between 0 to 65535. The range is divided into three major group:

0 to 1023	Well known port numbers. Only special companies like Apple QuickTime, MSN, SQL Services, Gopher Services and other prominent services have these port numbers.
1024 to 49151	Registered ports; meaning they can be registered to specific protocols by software corporations.
49152 to 65536	Dynamic or private ports; meaning that they can be used by just about anybody.

So an port can be used too move programs, different applications and other kinds of data to one computer to another. As you can see it really serves it’s purpose. If you are interested in this service, there’s all kinds of software port you can download to your computer that will enable you to be able exchange data directly through the internet and other networks.

Last Updated Monday, November 19 2007 @ 08:21 pm PST