Active Directory on Proxmox – Windows Server 2025 Core, RSAT & Domain Join

Running a full Active Directory environment in your home lab doesn’t require a GUI-heavy Windows Server install. Server Core keeps the resource footprint small, it’s closer to how real enterprise environments run, and managing it entirely through PowerShell is a genuinely useful skill. In this guide I’ll walk through creating a Windows Server 2025 Core VM in Proxmox, promoting it to a domain controller, joining a Windows 11 machine to the domain, and installing RSAT so you can manage everything from a familiar GUI — without ever needing one on the server itself.

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🎥Watch the Video Tutorial

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💡Why Windows Server Core?

Server Core is Windows Server without the desktop experience — no Explorer, no Start menu, just a command prompt and PowerShell. It uses significantly less RAM and disk space than the Desktop Experience install, boots faster, and has a smaller attack surface. For a home lab domain controller it’s the right choice: lean, practical, and it mirrors what you’d encounter in a real enterprise environment. In this guide, our domain will be ithomelab.local and the domain controller will be named HLDC01 (Home Lab Domain Controller 01). The naming convention is deliberate — if you want to add additional domain controllers later for replication and redundancy, you can simply increment: HLDC02, HLDC03, and so on.

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🛠 What You’ll Need

• Proxmox VE installed — see: Proxmox VE Home Lab Setup
• Windows Server 2025 evaluation ISO (free 180-day eval) — uploaded to Proxmox
• A Windows 11 VM or physical machine to join to the domain
• Basic familiarity with PowerShell — all commands are provided below

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📋Step-by-Step Setup

1. Create the Windows Server 2025 Core VM in Proxmox

In the Proxmox web UI click Create VM. Work through the wizard with these settings:

• OS: Select your Windows Server 2025 ISO. Type: Microsoft Windows, Version: 11/2022/2025
• System: Machine: q35, BIOS: OVMF (UEFI). Add TPM — select your storage and set version to v2.0 (required by Server 2025)
• Disk: 60 GB, change disk type to SATA for out-of-the-box driver compatibility
• CPU: 2 cores — Server Core is lightweight and doesn’t need more for a home lab DC
• Memory: 4096 MB — more than enough for a Core installation
• Network: Change to VirtIO (or Intel E1000 if you prefer guaranteed out-of-box driver support). Bridge: vmbr0

Click Finish. Select the new VM, click Start, then open the Console. If you miss the initial boot prompt, press any key when you see the DVD ROM option to boot from the ISO.

2. Install Windows Server 2025 Core

Work through the Windows setup wizard:

• Language: your preference. Time/currency: set to your region (e.g. Australia)
• Keyboard: US Standard
• Click Install Now → accept the license terms
• Select edition carefully: choose Windows Server 2025 Standard — the top option without ‘(Desktop Experience)’. This is the Core installation
• Installation type: Custom (clean install)
• Select the detected disk and click Next

Windows installs and reboots automatically. Once complete, set the built-in Administrator password when prompted — you’ll disable this account later, but you need it to get started.

3. Rename the server

After first login you land at a Command Prompt. Switch to PowerShell and rename the server: The server restarts. After rebooting, send Ctrl+Alt+Delete via the Proxmox console extra keys panel and log back in as Administrator.

4. Set a static IP address

A domain controller must have a static IP. You can do this through the Server Configuration menu (option 8 in sconfig) or directly in PowerShell.

5. Install AD Domain Services and DNS

Wait for the installation to complete — it reports Success: True when done.

6. Promote to domain controller and create a new forest

Replace ithomelab.local with your preferred internal domain name. The NetbiosName is the short domain name used for legacy compatibility — typically the first part of your domain in uppercase: You’ll be prompted to set a Safe Mode Administrator Password (DSRM password) — this is used for AD recovery scenarios, so make it strong and store it somewhere safe. The server reboots automatically and comes back as a domain controller.

7. Create domain admin and standard user accounts

Log back in as Administrator. Drop to PowerShell and create your accounts:

8. Verify the admin account and disable the built-in Administrator

Before disabling the built-in Administrator account, reboot and confirm you can log in with the new domain admin account. In Proxmox console, send Ctrl+Alt+Delete → select Other User → log in as ITHOMELAB\\neo with the password you set. Once confirmed working, drop to PowerShell as Neo and disable the built-in Administrator:

9. Join a Windows 11 machine to the domain

On the Windows 11 machine, first update the DNS server to point to your domain controller:

• Go to Settings → Network & Internet → Ethernet → DNS server assignment → Manual
• Set Preferred DNS to your DC’s IP (e.g. 10.0.2.10)
• Set Alternate DNS to a public DNS (e.g. 8.8.8.8) as a fallback

Then join the domain:

• Go to Settings → System → About → Domain or workgroup
• Click Change → select Domain → enter ithomelab.local
• Enter your domain admin credentials when prompted (ITHOMELAB\\neo)
• Restart when prompted

10. Install RSAT on Windows 11

After the Windows 11 machine reboots and you log in with a domain account, install RSAT so you can manage Active Directory from a GUI:

• Go to Settings → System → Optional features → View features
• Search for RSAT
• Install RSAT: Active Directory Domain Services and Lightweight Directory Services Tools

Or install it via PowerShell as Administrator: Once installed, open Active Directory Users and Computers from the Start menu. You’ll see your domain, the default containers, and the user accounts you created.

11. Organise your domain with OUs

The default Active Directory containers (like the built-in Computers container) don’t support Group Policy. Move computers and users into proper Organisational Units so you can apply GPOs to them later. A clean OU structure to start with: Then move your user accounts and the Windows 11 computer object into the appropriate OUs using RSAT’s drag-and-drop interface, or via PowerShell:

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✅ Conclusion

You now have a lean Active Directory environment running in your home lab — a Server Core domain controller, a structured OU hierarchy, domain users with appropriate privilege levels, a joined Windows 11 machine, and RSAT for GUI management. It’s a solid foundation for practising Group Policy, deploying software via GPO, setting up DHCP and DNS, and anything else that requires a domain. The naming conventions and OU structure used here will scale cleanly as you add more machines and complexity. Next in the series: Monitor Your Home Lab Network with Wazuh on Proxmox 📺 Watch the full video guide here: https://youtu.be/Sjz1WUaj7cI If you found this helpful, like and subscribe to IT HomeLab Online on YouTube for more tutorials. ☕ Support the channel: Patreon · Buy Me a Coffee