Computer Ports: Usage & Role in Networking

Discover the wide range of computer connections

USB cable connection in laptop computer

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Computer ports are an essential feature of all computing devices. Ports provide the input and output interfaces the device needs to communicate with peripherals and computer networks.

The most important ports on computers are used for networking, for without them, the computer would be completely isolated and unable to communicate outside of itself.

Physical Ports

A port can be either physical or virtual. Physical network ports allow the connection of cables to computers, routers, modems, and other peripheral devices. Ports themselves are physically connected in one way or another to the motherboard.

Several different types of physical ports available on computer network hardware include:

Networking aside, other ports that exist on a computer include ones for video (like HDMI or VGA), mice and keyboards (PS/2), FireWire, and eSATA, among others.

Ports in Wireless Networking

While wired computer networks rely on physical ports and cables, wireless networks don't need them. Wi-Fi networks, for example, utilize channel numbers representing radio signaling bands.

However, wired and wireless networking can blend together via physical computer ports. For example, a network adapter plugged into a computer's USB port turns the wired computer into a wireless computer, thus bridging the gap between the two technologies using a port.

Internet Protocol Ports

Virtual ports are an essential component of Internet Protocol (IP) networking. These ports allow software applications to share hardware resources without interfering with each other.

Computers and routers automatically manage network traffic traveling via their virtual ports. Network firewalls also provide some control over the flow of traffic on each virtual port for security purposes. 

In IP networking, these virtual ports are structured via port numbers, from 0 through 65535. For example, port 80 is what lets you access websites through your web browser, and port 21 is associated with FTP.

Issues With Ports in Computer Networking

Physical ports can stop functioning for any of several reasons. Causes of port failure include:

  • Power surges (for devices physically connected to electric mains)
  • Water damage
  • Internal failure
  • Damage caused by the cable pins (e.g., inserting cables too forcefully, or by attempting to plug the wrong type of cable into a port)

Except for damage to pins, a physical inspection of the port hardware won't find anything obviously wrong. A failure of one port on a multiport device (such as a network router) doesn't affect the functioning of the other ports.

The speed and specification level of a physical port can also not be determined just by physical inspection. Some Ethernet devices, for example, operate at a maximum of 100 Mbps, while others support Gigabit Ethernet, but the physical connector is the same in both cases. Similarly, some USB connectors support version 3.0 while others only support USB 2.x or sometimes even USB 1.x.

The most common challenge a person faces with virtual ports is network security. Internet attackers regularly probe the ports of websites, routers, and any other network gateways. A network firewall greatly helps to guard against these attacks by limiting access to ports based on their number.

To be most effective, a firewall tends to be overprotective and will sometimes block traffic that a person wanted to allow. Methods for configuring the rules that firewalls use to process traffic—such as port forwarding rules—can be very difficult for non-professionals to manage.