Port 9100 (TCP) — Node Exporter

Prometheus node_exporter metrics.

🔒 Runs locally — your input never leaves this browser tab

Leaks host details. Restrict to your Prometheus server.

Check if port 9100 is open

On the server, see what is listening:

sudo ss -tulpn | grep ':9100 '

From another machine, test reachability:

nc -zv your-server.example.com 9100

With UFW (Ubuntu/Debian):

sudo ufw deny 9100

With firewalld (RHEL/AlmaLinux/Rocky):

sudo firewall-cmd --permanent --remove-port=9100/tcp && sudo firewall-cmd --reload