What is the role of the port and its

In the world of the web, there are two very important concept, it is a IP location, is a port. According to the IP address of the terminal communicate with each other can be found, according to the port can be found using the program to communicate with each other, that is, corresponding to the difference between the different port number to use program. And we can use some very useful programs such as iis7 server monitoring tools to explore what is the port, the port and the classification of

    the role of the port of

    a identifies the IP address of a host, but a host can provide a variety of services, like web services , ftp services, such as remote Desktop. How to identify different service it, the IP address of the display alone is not enough, and IP location service is one to many relationship, then you need to identify the port number.

    For example, we visited today headlines site, the browser using a random port greater than 1024, to obtain the IP address of the site of today's headlines through DNS, visit the web service port 80. The following figure shows the format of the TCP packet, i.e., the first two fields is the source port number and destination port number.

    Classification port

    port number is an integer in the range from 0 to 65535 (2 ^ 16-1), divided into well-known ports and dynamic ports.

    1) well-known port, well-known port that is well-known port, some convention. Ranges from 0 to 1023, such as the more common www 80, ftp is 21, telnet to 23, dns 53 and the like.

    2) dynamic ports, generally not assigned to a service for fixing, ranging from 1024 to 65535, are assigned dynamically. When a course about the use of necessary communications system, host assignment from an available port number for its use, when the program is closed, while the release of occupied port number.