Port 9200 (Elasticsearch)
Port 9200 is the default HTTP REST port of Elasticsearch and OpenSearch; nodes talk to each other on 9300. IANA registers 9200 for an unrelated WAP service.
- Service
- Elasticsearch
- Protocol
- TCP
- IANA registry
- Assigned to a different service: wap-wsp (WAP connectionless session service), TCP/UDP. The use described here is not registered.
- Commonly used by
Check if a port is open on your IP
We only check the address you are visiting from, one TCP port at a time. You cannot enter someone else’s address: this is not a port scanner.
Is it safe to open port 9200?
An Elasticsearch cluster open on 9200 without authentication exposes every index to anyone. Keep authentication and TLS enabled and do not publish 9200 to the internet.
“Port 9200 is already in use”: how to fix it
The error means another program is already listening on port 9200. Find its process ID (PID), then stop that program or start yours on a different port.
Windows (Command Prompt or PowerShell as administrator)
netstat -ano | findstr :9200taskkill /PID <PID> /FmacOS
lsof -nP -iTCP:9200 -sTCP:LISTENkill <PID>Linux
sudo ss -ltnp | grep :9200sudo lsof -i :9200sudo kill <PID>Replace <PID> with the number from the last column (Windows) or the PID column (macOS, Linux).
Why a port can look closed when your server is running
Most home networks sit behind a router doing NAT: the router owns the public address, and your computer has a private one such as 192.168.1.10. A connection from the internet reaches the router and stops there unless you add a port forwarding rule to your computer.
Many mobile and some home providers go further and use carrier-grade NAT (CGNAT): several customers share one public address, and your router itself gets an address from 100.64.0.0/10. Then no rule on your side can open a port; ask the provider for a public IP or use a tunnel or VPN service.
Even with forwarding in place, the firewall on the computer (Windows Defender Firewall, ufw, firewalld) must allow the port, and the program must listen on all interfaces (0.0.0.0), not only on 127.0.0.1.
UDP cannot be checked this way: a UDP service usually stays silent to packets it does not understand, so “no answer” means nothing. This check uses TCP only.
Frequently asked questions
What is port 9200 used for?
Port 9200 is the default HTTP REST port of Elasticsearch and OpenSearch; nodes talk to each other on 9300. IANA registers 9200 for an unrelated WAP service.
Is port 9200 TCP or UDP?
Port 9200 uses TCP. This use is not registered with IANA.
Is it safe to open port 9200?
An Elasticsearch cluster open on 9200 without authentication exposes every index to anyone. Keep authentication and TLS enabled and do not publish 9200 to the internet.
How do I free port 9200 if it is already in use?
Find the process: on Windows run netstat -ano | findstr :9200 and stop it with taskkill /PID <pid> /F; on macOS or Linux run lsof -i :9200 and stop it with kill <pid>.