Discover license servers

Updated: February 28, 2012

Applies To: Windows Server 2003, Windows Server 2008, Windows Server 2008 R2

Following is a history of license server discovery in Windows.

Windows NT

• Every terminal server had a local license server.

• Advantage: There were no issues with license server discovery.

• Disadvantage: There was no way to track client access licenses (CALs) easily.

Windows 2000 Server

• The license server must be installed on a domain controller.

• The license server is discovered by an RPC call to a domain controller in its own domain. It then chooses one of the license servers at random and requests a key pack. If no key pack is available, it then passes the request to an enterprise license server (domain discovery).

• The license server is discovered by an LDAP query, and is published in Active Directory Sites and Services (enterprise discovery).

• For workgroup mode, Broadcast is used to discover a license server.

Note

The DefaultLicenseServer (REG_SZ) registry key is used to override the license server discovery. Location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermService\Parameters

It has the following limitations:

• Only one license server could be specified.

• Admin Tools didn't use the registry key.

• License server discovery was still done.

See also

• Establishing preferred Windows 2000 Terminal Services license server

• Description of Terminal Services License Server discovery

Windows Server 2003

The license server can be installed on the domain controller or on a member server. If it is installed on the member server, auto-discovery by Terminal Services doesn't work.

Sequence:

1. Check in Registry for DefaultLicenseServer.

2. Check if the license server is installed on the terminal server.

3. Make an LDAP query to Active Directory (enterprise discovery).

4. Make an RPC call to the local domain controller within the same site; if it fails, go across site (domain discovery).

5. Stop the discovery as soon as you find the first license server.

Note

The LicenseServers (Key) registry key is used to override the license server. Each server is a key under LicenseServers and the NetBIOS, FQDN, or IP address can be used. Location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermService\Parameters

Windows Server 2003 Discovery Scope	Enterprise	Domain or Work Group
Why should you choose this scope?	This is the appropriate choice if your network includes several domains, and if you want to maintain one license server that can issue licenses to terminal servers across the different domains.	This is the appropriate choice if you want to maintain a separate license server for each domain.
Whom can I serve?	Terminal servers on the same site. Note The same site can have multiple domain controllers from multiple domains.	Domain: terminal servers in the same domain. Work group: terminal servers on the same subnet.
Where to install?	Only on a domain controller or a member server in a domain, not on a stand-alone server.	Does not have to be a domain controller, but if you want the license server to be automatically discovered by terminal servers that communicate with it, the computer on which you install the license server must be a domain controller.

See also

• Terminal Server license server roles and discovery

• How to override the license server discovery process in Windows Server 2003 Terminal Services

• The terminal server cannot locate the license server

• Terminal Services Licensing service discovery

• Windows Server 2003 Terminal Server licensing issues and requirements for deployment

Windows Server 2003 Service Pack 1 (SP1)

• The Terminal Services Installation Wizard supports the license server override.

• Includes added Group Policy support for the license server override.

Windows Server 2008

Windows Server 2008 Discovery Scope	Forest	Domain or Work Group
Why should you choose this scope?	This is the appropriate choice if your network includes several domains, and if you want to maintain one license server that can issue licenses to terminal servers across the different domains.	This is the appropriate choice if you want to maintain a separate license server for each domain.
Whom can I serve?	Terminal servers in the same forest because the license server is published in Active Directory.	Domain: terminal servers in the same domain. Work group: terminal servers in the same work group.
Where to install?	Only on a domain controller or a member server in a domain, not on a stand-alone server.	Does not have to be a domain controller, but if you want the license server to be automatically discovered by terminal servers that communicate with it, the computer on which you install the license server must be a domain controller.

See also

• Terminal Services License Server Discovery

• Specify the License Server Discovery Mode on a Terminal Server

Windows Server 2008 R2

1. Automatic license server discovery is no longer supported for an RD Session Host server that is running Windows Server 2008 R2. Instead, you must specify a license server for the RD Session Host server to use. For more information, see Specify a License Server for an RD Session Host Server to Use.

2. You need to configure the license server by using one of the following:

   • RD Licensing Manager

   • Group Policy setting

   • Registry setting

3. For the issuance of both Per Device and Per User CALs to work, you must configure the RD Session Host server and the Remote Desktop license server in one of the following ways:

   • Both servers in the same workgroup

   • Both servers in the same domain

   • Both servers in a trusted Active Directory domain or forest (two-way trust)

See also

• Remote Desktop License Server Discovery

• Change the Discovery Scope of a Remote Desktop License Server

• Review the Configuration of a Remote Desktop License Server

Related topics

• Troubleshooting Remote Desktop Licensing Issues