A common surprise on a Windows Server VPS is that only two people can be connected by Remote Desktop at once. This guide explains Windows RDP licensing: what is included, when you need Remote Desktop Services (RDS) and Client Access Licenses (CALs), and how to set it up correctly. Always confirm details with Microsoft's current licensing terms or your licence provider.
Before you start
- A Windows Server VPS or VM; see connect and secure RDP.
- Know how many people need to log in at the same time and whether they are administrators or end users.
What is included: administrative RDP
- Windows Server allows two simultaneous Remote Desktop sessions for administration without extra licences.
- This is for managing the server, not for giving users a desktop to work in.
- A third connection must disconnect one of the existing sessions.
When you need RDS and CALs
If users connect to run applications or work on desktops (for example staff using accounting software, or several traders on one server), you need the Remote Desktop Session Host role plus RDS CALs for those users or devices, on top of the Windows Server licence and any Windows Server CAL requirements.
Per-user vs per-device CALs
| Per User | Per Device | |
|---|---|---|
| Licensed | Each named person | Each connecting computer |
| Best when | People use several devices | Shift workers share a few PCs |
Setting up RDS (high level)
- Install the roles: Server Manager → Add Roles and Features → Remote Desktop Services installation (Quick Start is fine for a single server), or install the Session Host and Licensing roles individually.
- Activate the RD Licensing server and install your RDS CALs.
- Point the Session Host to the licensing server and set the licensing mode (Per User or Per Device) via Server Manager or Group Policy.
- Add users to the Remote Desktop Users group.
The grace period
After installing the Session Host role, Windows allows unlicensed connections for a limited grace period (commonly 120 days). When it ends, connections are refused until valid CALs are configured. Plan licensing before the deadline.
Security reminders
- Restrict RDP by IP, use strong passwords and Network Level Authentication, and consider an RD Gateway or VPN; see Windows firewall rules.
- Do not expose port 3389 to the whole internet.
Troubleshooting
- "The number of connections to this computer is limited": two admin sessions in use; log one off, or set up RDS with CALs.
- "No Remote Desktop license servers available": grace period expired or licensing server not configured.
- Users cannot log in but admins can: users are not in Remote Desktop Users.
Frequently asked questions
Can I avoid CALs with registry tweaks?
Bypassing licensing limits breaks Microsoft's terms. Use proper RDS CALs.
Does my VPS provider include RDS CALs?
Usually not by default; some offer them as an add-on. Check your plan.
Do administrators need RDS CALs?
Not for the two administrative sessions, as long as RDS Session Host is not used for their work sessions.