Do You Plug Ethernet Into The Router or Modem?

This is a common question for users on older home internet setups where the modem and router are still separate. There can be ports and cables lying around everyone and it’s difficult to know how to just get online. What goes into what? For example, do you plug your ethernet cable from your device into the router or the modem?

There’s actually different ways you can do this, but here’s a bottom line answer:

In general, your ethernet cable can be plugged into either your modem or router, but it is better to connect to the router, since it provides more ethernet connections, plus Wi-Fi, plus firewall protection that a modem doesn’t.

In other words, you can hard wire your connection into either a modem or a router, but the router is almost always a better option.

Let’s look at the different possible setups to explain why.

Connecting Ethernet Directly To Your Modem

Let’s cover the simplest scenario – you can technically connect any device by ethernet directly into a standalone modem if you like, bypassing the router entirely.

Then, as long as you have an installed and activated internet service, your modem will go into the phone line and connect you to the internet.

There’s no problem in theory with this – you can hard-wire one device up to your modem and get online without any problem.

However, here’s the limitations to plugging into your modem direct:

  • That’s all you can connect up – just one device and only by ethernet. Almost all modems have only one ethernet port and that’s it, so devices would have to take turns unplugging and plugging back in to use the internet via the single modem port only (not very efficient)
  • Modems also don’t broadcast any Wi-Fi – so other devices that can only use wireless can’t connect at all to a modem.
  • Modems offer no firewall functionality.

Connecting Ethernet Into Your Router

While it’s technically possible, we start to see the limitation of plugging ethernet directly into your modem, and we see why Wi-Fi routers exist – to open up more connections and allow better network management.

The most efficient and common home network setup is to connect your modem to a separate Wi-Fi router, and then connect your devices to the router’s ethernet ports instead.

Here are the general steps to get set up this way:

Step #1 – Plug an RJ-45 ethernet cable into the WAN/DSL/ADSL/Internet Port on your router (the differently colored single port separate from the LAN ports):


Step #2 – Connect the other end of this ethernet cable to the single ethernet port on your separate modem:

The modem then also goes out to the phone line via a slightly smaller RJ-11 port/cable.

Step #3 – Connect devices to one of your router’s (normally 4 LAN/ethernet) ports:


Just plug them straight into one of the 4 (often yellow or red) ethernet ports, and as long as your setup runs as in previous steps, and you have a live and activated internet service, then you should be able to access the internet on your devices via these ports.

Here are the benefits of this typical setup:

  • It provides more ethernet connections – usually 4 LAN ports on a router to plug devices in, versus just one on a modem.
  • Routers broadcast one or more Wi-Fi networks to connect smaller devices like tablets/phones etc. Modems don’t offer Wi-Fi and are useless to devices that need wireless connections.
  • Routers offer firewall protection, DHCP to assign IP addresses, and other general network management functions that a modem can’t do.

The Interdependence Of Modems & Routers

The whole jargon-fest of modems, router, ethernet etc. can be confusing, but hopefully we’ve managed to clear it up a bit in this post. You can technically plug a device by ethernet into either a modem or a router, and it will work, but in general, it’s better to go into the router.

The truth is that realistically, routers and modems both need and complement each other to make a home network function properly.

Here’s a key summary of the interrelation between modems and routers:

  1. Except for providing 1 wired connection, modems do not work on their own and need to be connected to a router to allow devices to use the internet.
  2. Routers by themselves are also no good, and need to be connected to a modem (built-in or separate) to allow internet access.
  3. It is almost always better to connect a modem to a router, and then connect devices to the router, rather than connecting to the modem directly.


Online gamer and general home networking enthusiast. I like to create articles to help people solve common home networking problems.

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