Port 3000: Dev server
TCP 3000 is the port for Common development / app port (Node.js, Grafana, Rails). Put a reverse proxy with HTTPS on 443 in front instead of exposing it directly.
| Service | Common development / app port (Node.js, Grafana, Rails) |
|---|---|
| Protocol | TCP |
| Exposure risk | Medium: expose with care |
| Range | Registered (1024–49151) |
What port 3000 does
Not formally reserved for these, but it is the default for Node.js frameworks (Express examples, Next.js dev), Ruby on Rails and Grafana.
Should port 3000 be open?
Put a reverse proxy with HTTPS on 443 in front instead of exposing it directly.
Find what's listening on port 3000
- Linux:
sudo ss -tulpn | grep :3000 - macOS:
sudo lsof -nP -i :3000 - Windows:
netstat -ano | findstr :3000, then look up the PID in Task Manager.
Open or block it in a firewall
- ufw:
sudo ufw allow 3000/tcp(ordeny) - firewalld:
sudo firewall-cmd --add-port=3000/tcp --permanent && sudo firewall-cmd --reload - Windows:
New-NetFirewallRule -DisplayName "Port 3000" -Direction Inbound -Protocol TCP -LocalPort 3000 -Action Allow
Port assignment per the IANA Service Name and Transport Protocol Port Number Registry. Test several ports at once with the port scanner, or any port with the open port checker.
Questions about port 3000
What is port 3000 used for?
Common development / app port (Node.js, Grafana, Rails). Not formally reserved for these, but it is the default for Node.js frameworks (Express examples, Next.js dev), Ruby on Rails and Grafana.
Is port 3000 TCP or UDP?
TCP. Dev server uses TCP port 3000.
Is it safe to open port 3000?
Medium: expose with care. Put a reverse proxy with HTTPS on 443 in front instead of exposing it directly.
How do I check if port 3000 is open?
Use the checker on this page: it connects to your host on TCP 3000 from the internet. Locally, run
nc -vz host 3000 (macOS/Linux) or Test-NetConnection host -Port 3000 (PowerShell). To see what is listening on your own machine, run ss -tulpn | grep :3000 (Linux) or netstat -ano | findstr :3000 (Windows).