Friday, 28 December 2012

Ports (tcp / udp)

Ports:

Simply, The term port can refer to either physical or virtual connection points.

Well Known Ports: 0 through 1023:

The well-known port numbers are the port numbers that are reserved for assignment by the Internet Corporation for Assigned Names and Numbers (ICANN) for use by the application end points that communicate using the Internet's Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). Each kind of application has a designated (and thus "well-known") port number. For example, a remote job entry application has the port number of 5; the Hypertext Transfer Protocol (HTTP) application has the port number of 80; and the Post Office Protocol Version 3 (POP3) application, commonly used for e-mail delivery, has the port number of 110. When one application communicates with another application at another host computer on the Internet, it specifies that application in each data transmission by using its port number. The well-known ports cover the range of possible port numbers from 0 through 1023.

Registered Ports: 1024 through 49151:

The registered port numbers are the port numbers that companies and other users register with the Internet Corporation for Assigned Names and Numbers (ICANN) for use by the applications that communicate using the Internet's Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). In most cases, these applications run as ordinary programs that can be started by nonprivileged users. The registered port numbers are in the range from 1024 through 49151. They follow in sequence the well-known port numbers, which are, in most cases, applications that can only be started by privileged users, such as the Hypertext Transfer Protocol (HTTP) and Post Office Protocol Version 3 (POP3) applications. When one application communicates with another application at another host computer on the Internet, it specifies that application in each data transmission by using its port number. The registered ports are numbered from 1024 through 49151.

Dynamic/Private : 49152 through 65535:

The dynamic port numbers (also known as the private port numbers) are the port numbers that are available for use by any application to use in communicating with any other application, using the Internet's Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). When one application communicates with another application at another host computer on the Internet, it specifies that application in each data transmission by using its port number. The port numbers range from 0 through 65535. However, certain port numbers - the well-known port numbers and the registered port numbers - are registered and administered by the Internet Corporation for Assigned Names and Numbers (ICANN) for use by certain classes of applications. The dynamic port numbers are in the highest range, from 49152 through 65535.

For more details: http://searchnetworking.techtarget.com/

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