A network port is a common way to reference three different things. Network access points, such as a home router, are often called network ports. The second common meaning refers to the actual location where a network cable plugs into an access point or a computer. These physical ports provide users access to local networks and the Internet. The last common usage for this type of port references the software system that allows computers to handle multiple networking tasks at the same time. These ports divide network traffic into a series of individual feeds so information and services stay separate.
When users refer to a hardware network port, it is typically one of two things. A network access point, such as a router, switch or modem, may be referred to as a port. This is especially common when talking about wireless networks, where the term ‘wireless port’ is used to refer to the router to which the system connects. The other common hardware network port is the actual connection to the network. In this case, the small rectangular hole where the ethernet cable connects to the computer, router or modem, is the port. This usage is a holdover from older computer terms such as serial port or communications port.
The last usage for network port is based on software rather than hardware. With this definition, a port is software-based, non-physical, location within your computer. These ports split network traffic and network-based services into segments. The computer is able to individually prioritize and process these segments, just as it does with internal processes.
By splitting up the network feeds, a computer can send and receive from multiple sources at the same time. Each active network port is capable of having information sent directly to it. For instance, if a process was running on port 1000, then that specific network port could both send and receive information. Outgoing information would have port 1000 referenced as the sender and information sent back would go specifically to port 1000. If a computer were maintaining a hundred different ports, they would all be doing the same thing.
In this situation, a network port follows certain guidelines across all computers. The port may be any number from zero to 65535, but many of the ports below 1024 are needed for specific Internet tasks. Processes such as Web browsing, e-mail and telnet all have predefined ports where the computer constantly monitors activity. Other programs, such as video games or downloading programs, have user or program defined ports that the computer only activates when the program is running.