Network Monitor for Mac

$ ifconfig
$ netstat -rn
$ scutil --dns

What it’s for

Network Monitor shows what macOS knows about your connection right now: whether it’s up, which interface carries it, your Mac’s addresses, the router, and any VPN tunnel. It keeps watching while it runs, and logs each change with its time.

Use it when

• The connection drops for a moment now and then, and you want to see when and how.
• You need your Mac’s local IP address or the router’s.
• You want to see which interface macOS is using: Wi-Fi, Ethernet or a VPN.

Reading the result

Click Start.

• Status says whether the connection is usable. When it isn’t, the reason macOS gives is shown, such as Local Network access being denied.
• Expensive is a connection macOS treats as costly, such as an iPhone hotspot or cellular. Constrained means Low Data Mode is on.
• Capabilities show whether IPv4, IPv6 and DNS work on this connection.
• Gateway is your router’s address.
• Interface lists each network interface with its addresses. In use marks the one carrying your traffic, and a VPN tunnel is named as one.
• Changes logs every switch, drop and return while monitoring runs.

What you might see

• IPv6 not supported. Many home networks are IPv4 only. That’s fine.
• An address starting with 169.254. The Mac didn’t get an address from the router. Restarting the router usually fixes it.
• Several Wi-Fi to Ethernet changes in a row. A loose cable, a dock waking up, or Wi-Fi roaming between access points.

Options worth knowing

• Stopped, the screen keeps the last reading and says when it was taken.
• Copy puts everything on screen on the clipboard, for a support request.
• Everything here is read from the Mac itself. Nothing is sent over the network.

Related

• IP addresses.
• Internet Check, to test the connection, not just watch it.
• The menu bar item shows your public IP and VPN state all the time.