Listening TCP and bound UDP
Every TCP port in the LISTEN state and every bound UDP port, with the process that owns it and its user.
Every open port and the app behind it
See every port your Mac is listening on, which app owns it, and whether other machines can reach it or only your Mac.
| Port | Protocol | Process | User | Listening on |
|---|---|---|---|---|
| 22 | TCP | sshd | root | All interfaces |
| 53 | UDP | mDNSResponder | _mdnsresponder | All interfaces |
| 3000 | TCP | node | you | All interfaces |
| 5000 | TCP | ControlCenter | you | All interfaces |
| 5432 | TCP | postgres | you | Localhost only |
| 7000 | TCP | ControlCenter | you | All interfaces |
| 8080 | TCP | java | you | 127.0.0.1 |
Illustration of the Ports view.
Reachable or local-only
Each port shows where it listens: all interfaces, one address, or localhost only. The first two can be reached from other machines unless a firewall blocks them.
No sudo needed
Root daemons such as mDNSResponder on port 53 appear without sudo. lsof needs administrator rights to show those.
IPv4 and IPv6 merged
When an app listens on both, you get one row per app and port instead of two.
Filters that cut the noise
Filter by protocol, hide client UDP ports (apps that bound a random port to send traffic), or hide localhost-only ports.
Copy and reveal
Right-click to copy the port, PID, address or process path, or reveal the program in Finder.
How it works
LightAtom reads the kernel’s list of sockets once a second, the same data lsof -i and netstat -an show, but for every process and without sudo.
UDP has no listening state, so “bound UDP” also includes clients that grabbed a random port to send from. Turn on Hide client UDP to see only real servers.
“Reachable from the network” describes how a port is bound. Whether the internet can reach it also depends on your router and the macOS firewall; a port checker tests that from outside.
Questions
How do I see which app is using a port on my Mac?
Open the Ports tab: each row shows the port, protocol, the process that owns it and its user. In Terminal, the equivalent is sudo lsof -nP -i :PORT.
What’s using port 5000 or 7000 on my Mac?
On recent macOS versions it’s usually ControlCenter, which runs the AirPlay Receiver. Turn off AirPlay Receiver in System Settings › General › AirDrop & Handoff to free those ports.
Does “all interfaces” mean the port is open to the internet?
Not necessarily. It means other devices on your networks can connect unless the macOS firewall blocks it. From the internet, your router usually blocks it unless you set up port forwarding.
Can I close a port from LightAtom?
A port closes when the app that owns it stops listening. LightAtom shows which app that is; quit the app or change its settings. You can copy the PID or reveal the program in Finder.