DevOps & Cloud
Risk: High
Port 50000 — Jenkins Inbound Agent (JNLP) Listener
Port 50000 is the default TCP port for Jenkins controller servers to communicate with inbound JNLP (Java Network Launch Protocol) build agents and worker nodes.
PORT NUMBER
50000
PROTOCOL
TCP
DEFAULT PROCESS
java (jenkins)
FIREWALL TARGET
50000/tcp
Instant Terminal Fixes for Port 50000
macOS & Linux Terminal
1. Check who is listening on port 50000:
sudo lsof -i :50000 || sudo ss -tulpn | grep ":50000 "2. Kill process occupying port 50000 (EADDRINUSE fix):
sudo systemctl stop jenkins3. UFW Firewall Allow rule:
sudo ufw allow from 10.0.0.0/8 to any port 50000 proto tcpWindows PowerShell (Admin)
1. Check listening port:
Get-NetTCPConnection -LocalPort 500002. Force kill process on port 50000:
Stop-Service Jenkins -Force3. Docker Port Forwarding Mapping:
docker run -p 8080:8080 -p 50000:50000 -d jenkins/jenkins:ltsCommon Error Encountered
Jenkins agent failed to connect to controller on port 50000: Connection refused.
Security Advisory & Hardening
Restrict port 50000 strictly to build agent IP addresses. Disable JNLP protocols that do not use modern TLS encryption.
Frequently Asked Questions
Port 50000 Questions & Answers
Common questions regarding default services, kill commands, and firewall configurations.
Port 50000 is commonly used for Jenkins Inbound Agent (JNLP) Listener. Port 50000 is the default TCP port for Jenkins controller servers to communicate with inbound JNLP (Java Network Launch Protocol) build agents and worker nodes.