9090
Prometheus monitoring or Cockpit Linux web management
Prometheus / Cockpit Web UI
What is port 9090?
Port 9090 is shared by Prometheus (monitoring) and Cockpit (Red Hat) — a web-based Linux server management UI. Cockpit allows browser-based management of Linux servers including services, storage, networking, containers, and system updates. It comes pre-installed on RHEL, Fedora, and CentOS. This port should be accessible only within a trusted network.
Quick checks
$
nc -zv example.com 9090
$
nmap -p 9090 example.com
$
telnet example.com 9090