A port is place where a computer or communication device is connected to another device using some sort of arrangement like socket and plug. Usually a computer has two kinds of ports. One is serial port and the other is parallel port. A serial port is useful to connect computers with peripherals such as scanners, where as a parallel port useful to connect computers with printers. It is possible to transfer bit by bit with serial port and multiple bits by parallel port. 

A port also means a connecting area of a computer with Internet using different methods. These methods are called protocols. We have protocols such as TCP/IP. The protocol is the way a computer program chooses certain port in the server. Port numbers start from 0 and end with 65535. Each service will have a particular port number. For example port numbers from 0 to 1021 are reserved for some privileged services. Port number 80 is allotted for services of HTTP.  That is why we need not specify http while typing URLs.

To port means moving a program from one operating platform in which it is developed to another operating platform in where it can be applied and used. Porting and Portability are the words related to this activity. This is intended to minimize work while moving one application program from one environment of certain operating system to environment of another operating system. 

Open Port Test relates to the connecting a computer with Internet. Many Internet Service Providers block certain ports to avoid and minimize spam, viruses and other malicious programs. Thus potentially harmful material is restricted from entering into computers. Open Port Test is useful to know your IP address. It is also useful to know what ports in your computer connection are open. There are hundreds of free open port checker tools on the web to perform Open Port Test. The test tells us whether our Internet set up is correct or not. It enables you to know if the server applications of your computer are interrupted by any firewall. Generally port number 80 relates to web, port number 25 relates to outgoing mail and POP port is 110. The test lets us know where the problem lies when we receive error messages like ‘connection refused', by scanning the application, the server and the computer.