What Is an Ethernet Port?

Learn what Ethernet ports are and where they are used

Illustration of an Ethernet port on a laptop, both wide view and up close

 Lifewire / Derek Abella

An Ethernet port (also called a jack or socket) is an opening on computer network equipment that Ethernet cables plug into. Their purpose is to connect wired network hardware in an Ethernet LAN, metropolitan area network (MAN), or wide area network (WAN).

Ethernet is pronounced with a long "e" as in the word eat. Ethernet ports go by other names also, such as LAN ports, Ethernet connections, Ethernet jacks, LAN sockets, and network ports.

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Everything You Need to Know About Ethernet Ports

What Ethernet Ports Look Like

Ethernet connections are found on the back of a computer or the back or side of a laptop. A router may have several Ethernet ports to accommodate multiple wired devices on a network. The same is true for other network hardware like hubs and modems.

An Ethernet port accepts a cable that has an RJ-45 connector. The alternative to using such a cable with an Ethernet port is Wi-Fi, which eliminates the need for both the cable and the port.

An Ethernet port is a little wider than a phone jack. Because of this shape, it's impossible to neatly fit an Ethernet cable into a phone jack, which makes it a little easier when plugging in cables.

This is what an Ethernet port looks like. It's a square with a couple of rigid areas at the bottom.

Gigabit Ethernet Switch.
Michael Schwarzenberger / Pixabay

The Ethernet cable is built the same way, usually with a clip to hold the cable in the Ethernet port.

An Ethernet cable.
Jorge Guillen / Pixabay

Ethernet Ports on Computers

Most desktop computers include one built-in Ethernet port that is used to connect the device to a wired network. A computer's built-in Ethernet port is connected to its internal Ethernet network adapter, called an Ethernet card, which is attached to the motherboard.

Laptops usually have an Ethernet port, too, to connect to a network that doesn't have wireless capabilities. An exception is the MacBook Air, which doesn't have an Ethernet port but does support connecting an Ethernet dongle to a USB port on the computer.

Troubleshoot Ethernet Port Issues

If your computer experiences internet connectivity issues, the Ethernet port is the first place to look.

Here are three reasons for connectivity issues:

  • The network cable is unplugged. This condition often results in a network cable is unplugged error. This error message appears when a computer or laptop is moved, which can knock the cable out of the Ethernet port.
  • The network card is unseated. If the computer has been moved around, the Ethernet card may come unseated from the expansion slot on the motherboard.
  • Network card drivers are corrupt or missing. Something else related to the Ethernet port is the network driver for the network card, which can become outdated, corrupt, or missing. One of the easiest ways to install a network driver is with a free driver updater tool.

Ethernet Ports on Routers

All popular broadband routers feature one or more Ethernet ports. With this setup, multiple wired computers in a network can reach the internet and the other connected devices on the network.

An uplink port (also called a WAN port) is a special Ethernet jack on a router that connects to a broadband modem. Wireless routers include a WAN port and typically four additional Ethernet ports for wired connections.

Ethernet Ports on Consumer Electronics

Other types of consumer gadgets (such as video game consoles, digital video recorders, and televisions) include Ethernet ports for home networking. Another example is Google Chromecast, for which you can buy an Ethernet adapter so that you can use Chromecast without Wi-Fi.