How to scan your local network for connected devices on macOS

· 10base-t interactive

You can list the devices on your local network from a Mac in several ways, and which one you want depends on how much you need to know about each device.

What macOS gives you out of the box

macOS ships with the pieces you need for a rough answer. Open Terminal and run:

arp -a

That prints the ARP table: the IP and MAC address of every device your Mac has recently exchanged traffic with. It is fast and requires nothing extra, but it only lists devices your Mac has already talked to, and it gives you no names — just addresses.

To populate the table first, ping the broadcast address for your subnet, wait a moment, then read the table again:

ping -c 3 192.168.1.255
              arp -a

Bonjour fills in some of the gaps. dns-sd -B _services._dns-sd._udp browses the services devices advertise about themselves, which is how you learn that something at 192.168.1.42 calls itself a printer.

These tools answer "what addresses are in use". They do not answer "what is that thing", which is usually the question you actually have.

Where a scanner earns its place

A dedicated scanner sweeps the subnet rather than waiting for traffic, and then tries to identify what it found: resolving hostnames, matching the MAC address prefix against the IEEE vendor registry to name the manufacturer, and reading Bonjour advertisements. The result is a list of devices with names and manufacturers rather than a column of numbers.

IP Scanner does this on macOS, iOS and visionOS. It keeps a persistent record of the devices it has seen, so you can name them yourself, and it will tell you when something new appears on the network — which is the practical way to notice a device that should not be there.

A change worth knowing about on macOS 27

Starting with macOS 27, Apple blocks sandboxed applications from reading the system ARP table. Every Mac App Store app is sandboxed, so this affects all App Store network scanners, not one in particular — MAC addresses and the vendor names derived from them stop being available to them.

Terminal's arp -a is unaffected, as are applications distributed outside the App Store. We wrote up the change, who it affects, and the ways around it in macOS 27 blocks MAC addresses for App Store apps.

Frequently asked questions

Does macOS have a built-in network scanner?

Not a graphical one, but it has the underlying tools. arp -a in Terminal lists the IP and MAC addresses of devices your Mac has recently communicated with, and dns-sd browses Bonjour service advertisements. Neither sweeps the network on its own or identifies devices by name.

Why does a scan show devices I do not recognise?

Most unfamiliar entries are ordinary hardware announcing itself under an unhelpful name — smart plugs, TVs, printers, and set-top boxes often report a bare model number or nothing at all. Matching the MAC address prefix to a manufacturer usually identifies them.

Why do some devices show no MAC address?

Two common reasons. The device may be on a different subnet, reachable through a router that does not pass ARP. Or, on macOS 27 and later, the app may be sandboxed and no longer permitted to read the ARP table at all.

Is scanning my own network legal?

Scanning a network you own or administer is routine and is what these tools are built for. Scanning networks you do not control is a different matter and may breach the operator's terms or local law.