Port 9090 / TCP
Prometheus Server
Port 9090 – Prometheus Server Protocol Specification
Technical analysis, security advisories, vulnerability mitigation, and firewall syntax for TCP/UDP port 9090 (Prometheus Server).
Port Number
9090
Transport Protocol
TCP
Port Range Type
Registered (1024-49151)
Default Status
Restricted / LAN
Service Description & Architectural Context
Prometheus time-series metrics collection server and web dashboard.
IANA / RFC Designation:
Port 9090 is assigned to Prometheus Server under the Internet Assigned Numbers Authority (IANA) service name registry. In enterprise infrastructure and homelab setups, services listening on this port must follow the principle of least privilege.
Security Analysis & Attack Surface Assessment
Contains sensitive operational topology data. Place behind reverse proxy with SSO.
Hardening Recommendations:
- Do not expose port 9090 to public WAN interfaces unless authenticated TLS or VPN wrapping is strictly enforced.
- Enforce rate-limiting using Fail2ban, CrowdSec, or cloud edge DDoS protection.
- Audit active listening sockets locally:
ss -tulpn | grep :9090ornetstat -ano | findstr :9090.
Firewall Rule Snippets for Port 9090
UFW (Ubuntu / Debian Linux)
sudo ufw allow 9090/tcp
iptables (Standard Linux Kernel)
sudo iptables -A INPUT -p tcp --dport 9090 -j ACCEPT
Windows PowerShell (Defender Advanced Firewall)
New-NetFirewallRule -DisplayName "Allow Port 9090" -Direction Inbound -LocalPort 9090 -Protocol TCP -Action Allow