Give a device the same address every time#

You will end up with a device that always gets the same address from the router's DHCP server, without configuring anything on the device. This is what you want for a printer, a NAS, a camera, or anything a firewall rule or a port forward names by address.

Before you start#

The operator role and a licence.
A scope on the device's network.

Step 1 — Find the device#

Services → DHCP, IPv4 tab. The Leases table lists every device that has an address; the Filter box narrows it by name, address or MAC prefix.

Step 2 — Reserve its address#

Click the device's lease. New reservation opens with its MAC address and the address it has now, in the scope that address belongs to.

Give it a Name — letters, digits, hyphens and dots. It is what you will recognise it by in the table and in the pending changes.
Keep its address, or change it. The address must be inside the scope, and the form says which reservation holds an address or a MAC that is already taken.
Add reservation, then apply.

A device that has never had a lease is added the same way from Add reservation on the Reservations panel, typing its MAC address.

An address inside a pool is fine: the server never offers a reserved address to anybody else.

Step 3 — Make the device ask again#

A reservation does not take a lease away from a device that already has one. Wait for the lease to renew, or restart the device.

Check it worked#

The reservation shows Active, on the Reservations panel, once the device holds its address. The Leases table shows the address against the device's MAC.

And the device is where you expect it:

bash

ping -c 3 192.0.2.10

Its own DNS servers or router#

A device that needs a different DNS server or gateway from the rest of the network — a host pinned to an upstream resolver, a machine that routes through another gateway — gets them on its reservation. Click it, and under Handed to this device instead of the scope’s add its DNS servers and Default router. The OPNsense importer writes these for a host the old router pinned to its own resolver.

For options the router cannot set per device, such as a boot file, dnsmasq as an app is the answer.

Changing and undoing it#

Click the reservation: change its address, its MAC or its options, and save. Delete reservation removes it after asking. The device keeps its current lease until it renews.