Deploy a Private KMS Server on Your Own VPS

This tutorial explains how the KMS protocol works and how to deploy a private KMS server on a Linux VPS for learning and research purposes only. All steps reference open-source projects hosted on GitHub.

Why Self-Host a KMS Server?

  • ✓ Learn how the KMS activation protocol works in practice
  • ✓ Study client-server communication on port 1688
  • ✓ Experiment with Volume Licensing in a lab environment
  • ✓ Avoid relying on third-party public KMS nodes

Prerequisites

  • • A Linux VPS (Ubuntu 20.04+ or Debian 11+ recommended)
  • • Root or sudo access via SSH
  • • Basic familiarity with Linux command line
  • • Port 1688 open in firewall

KMS Protocol Architecture

Microsoft KMS (Key Management Service) is a client-server activation model designed for enterprise environments. The client sends an activation request to the KMS server on TCP port 1688, and the server responds with a license token valid for 180 days. The client automatically renews every 7 days.

  1. 1 Client runs slmgr /skms your-server-ip to set KMS host
  2. 2 Client runs slmgr /ato to send activation request
  3. 3 KMS server validates the GVLK and responds with a token
  4. 4 Client is activated for 180 days, auto-renews every 7 days

Setup Steps

Step 1: Get a VPS

Choose a VPS provider and create a Linux instance. Any provider with 1 vCPU + 512MB RAM is sufficient — KMS uses almost no resources.

Step 2: Install vlmcsd

vlmcsd is an open-source KMS emulator. You can find it on GitHub (search for vlmcsd). Below are the general installation steps:

# Download the latest release from GitHub
cd /tmp
# wget https://github.com/.../vlmcsd-...-linux-x64
# chmod +x vlmcsd
# mv vlmcsd /usr/local/bin/

Step 3: Open Firewall Port 1688

KMS uses TCP port 1688. Make sure it is open in your firewall:

# UFW (Ubuntu/Debian)
sudo ufw allow 1688/tcp

# firewalld (CentOS/RHEL)
sudo firewall-cmd --permanent --add-port=1688/tcp
sudo firewall-cmd --reload

Step 4: Start the Service

Run vlmcsd in the background:

# Start vlmcsd (runs as daemon by default)
vlmcsd

# Verify it's running
netstat -tlnp | grep 1688

Step 5: Connect from Client

On your Windows machine, open CMD/PowerShell as admin:

slmgr /skms YOUR_VPS_IP
slmgr /ato

Alternative: Docker Deployment

If you prefer Docker, search for vlmcsd images on Docker Hub:

docker run -d --name vlmcsd -p 1688:1688 --restart=always mikolatero/vlmcsd

Auto-Start on Boot (systemd)

Create a systemd service file to keep vlmcsd running after reboot:

sudo tee /etc/systemd/system/vlmcsd.service << 'EOF'
[Unit]
Description=vlmcsd KMS Emulator
After=network.target

[Service]
Type=forking
ExecStart=/usr/local/bin/vlmcsd
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

sudo systemctl daemon-reload
sudo systemctl enable vlmcsd
sudo systemctl start vlmcsd

Verify Your Server

Use our KMS Server Status Check tool to test if your server is reachable on port 1688.

→ Use our KMS Server Status Check tool to test if your server is reachable on port 1688.

Important Notice

  • • This tutorial is for learning and research only. Do not use it for unauthorized activation.
  • • vlmcsd is a third-party open-source project. We do not host or distribute the software.
  • • For production environments, please use official Microsoft Volume Licensing.
  • • KMS activation is valid for 180 days and requires periodic renewal.