Port
1.In computer networking, a port is an endpoint of communication in an operating
system. While the term is also used for hardware devices, in software
it is a logical construct that identifies a specific process or a type
of service.
A port is always associated with
an IP
address of a host
and the protocol type of the communication, and thus completes
the destination or origination address of a communications session. A port is
identified for each address and protocol by a 16-bit number, commonly known as
the port number.
2.In programming, a port (noun) is a "logical connection
place" and specifically, using the Internet's protocol, TCP/IP, the way a client program specifies a particular server program
on a computer in a network. Higher-level applications that use TCP/IP such as
the Web protocol, Hypertext Transfer Protocol, have ports with preassigned
numbers. These are known as "well-known ports" that have been
assigned by the Internet Assigned Numbers Authority (IANA). Other application processes are given port numbers dynamically
for each connection. When a service (server program) initially is started, it is said to bind to its designated port number. As any client program wants to use that server, it also must
request to bind to the designated port number.
Port numbers are from 0 to 65535. Ports 0 to 1024 are reserved for
use by certain privileged services. For the HTTP service, port 80 is defined as
a default and it does not have to be specified in the Uniform Resource Locator
(URL).
http://searchnetworking.techtarget.com/definition/port
