Prometheus Pushgateway
What is Port 9091?
Port 9091 is the default port for the Prometheus Pushgateway, a component that allows ephemeral and batch jobs to push their metrics to Prometheus. While Prometheus normally pulls (scrapes) metrics from targets, the Pushgateway acts as an intermediary for jobs that cannot be scraped — they push metrics to the gateway, and Prometheus scrapes the gateway. Port 9091 is also used by Transmission BitTorrent client's web interface. In the Prometheus ecosystem, the Pushgateway is used sparingly, as Prometheus is designed primarily for pull-based scraping.
Common Uses
- Prometheus metrics push endpoint
- Batch job metric collection
- Short-lived process metric capture
- Transmission BitTorrent web interface
Technical Details
Copy-paste commands to check port 9091 (Prometheus Pushgateway) from your terminal
Test connectivity
nc -zv example.com 9091
curl -v --max-time 5 http://example.com:9091/
telnet example.com 9091
nmap -p 9091 -sV example.com
(echo > /dev/tcp/example.com/9091) 2>/dev/null && echo "open" || echo "closed"
Open port in firewall
sudo ufw allow 9091/tcp
sudo iptables -A INPUT -p tcp --dport 9091 -j ACCEPT
sudo firewall-cmd --permanent --add-port=9091/tcp && sudo firewall-cmd --reload
Security Considerations
The Pushgateway should be protected from unauthorized metric pushes that could poison monitoring data. Use authentication via a reverse proxy. Restrict access to authorized job runners. In Kubernetes, use network policies to limit access.
Popular Ports Reference
The most commonly used and referenced network ports