An IP address is a unique identifier for a specific device on your network. The router assigns them to these devices using Dynamic Host Configuration Protocol (DHCP). As you connect new devices to the network, they will be assigned the next IP address in the group, and if a device hasn’t connected in a few days, its IP address will “expire” so it can be assigned to something else.
For everyday use, this is perfectly fine, and you’ll never notice it happening in the background. But if you regularly SSH on your Raspberry Pi, power up your computer from across the house with Wake-on-LAN, or perform other advanced networking tasks, DHCP can become a nuisance.
It’s hard to remember which IP address is assigned to which device, and if they ever expire, you should look it up again. This is where a static IP address comes in handy. Here’s how to set them up.
What is a static IP address?
Instead of letting your router assign any IP address that is free at any given time, you can assign specific IP addresses to devices that you frequently access. For example, I have my home server set to 192.168.1.10, my main desktop to 192.168.1.11, and so on: easy to remember, sequential, and immutable.
You can assign these static IP addresses on the device itself, using, for example, the Windows network settings on each computer, or you can do it at the router level. If you do it through the router, it’s likely called DHCP reservation, although many people (and even some routers) still refer to it as a “static IP address.”
DHCP reservations allow you to easily configure everything in one place with all your computers in their default settings. Your computer will ask you for an IP address via DHCP, and your router will assign you the one you reserved, without your computer being any wiser.
How to set up
a
DHCP reservation To set up a DHCP reservation, you need to know your IP address, which is quite easy to find out. You should then head to your router’s settings page, usually typing your IP address into your browser’s navigation bar, and log in. (For mesh Wi-Fi systems, you’d use an app instead of a settings page.)
The location is different for each configuration page, but you’re looking for something called “DHCP reservations,” “static IP addresses,” or similar. On my Asus router, for example, it’s in the LAN configuration category.
To assign a reservation, you need the MAC address of the device in question. This is a unique string of characters that identifies a particular network adapter and you can usually find it in your router’s list of connected devices. Make sure you get the MAC address for the correct network adapter: If you have Ethernet and Wi-Fi on your computer, you have a MAC address for each.
On your router’s setup page, enter an easy-to-remember label for the device (such as “Whitson’s Desktop PC”), the MAC address, and the desired IP address. Save the changes and repeat the process for any other IP addresses you wish to reserve.
From that point on, those devices should have their reserved IP addresses assigned to them, and you’ll never have to look them up again.