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XenCenter Term XenServer CLI Term
Users Subjects
Add users Add subjects

Understanding Active Directory authentication in the XenServer environment

Even though XenServers are Linux-based, XenServer lets you use Active Directory accounts for XenServer
user accounts. To do so, it passes Active Directory credentials to the Active Directory domain controller.
When added to XenServer, Active Directory users and groups become XenServer subjects, generally
referred to as simply users in XenCenter. When a subject is registered with XenServer, users/groups are
authenticated with Active Directory on login and do not need to qualify their user name with a domain name.
Note:
By default, if you did not qualify the user name (for example, enter either mydomain\myuser or
myser@mydomain.com), XenCenter always attempts to log users in to Active Directory authentication
servers using the domain to which it is currently joined. The exception to this is the LSU account, which
XenCenter always authenticates locally (that is, on the XenServer) first.
The external authentication process works as follows:
1. The credentials supplied when connecting to a server are passed to the Active Directory domain controller
for authentication.
2. The domain controller checks the credentials. If they are invalid, the authentication fails immediately.
3. If the credentials are valid, the Active Directory controller is queried to get the subject identifier and group
membership associated with the credentials.
4. If the subject identifier matches the one stored in the XenServer, the authentication is completed
successfully.
When you join a domain, you enable Active Directory authentication for the pool. However, when a pool is
joined to a domain, only users in that domain (or a domain with which it has trust relationships) can connect
to the pool.
Note:
Manually updating the DNS configuration of a DHCP-configured network PIF is unsupported and might cause
Active Directory integration, and consequently user authentication, to fail or stop working.

Upgrading from XenServer 5.5

When you upgrade from XenServer 5.5 to the current release, any user accounts created in XenServer 5.5
are assigned the role of pool-admin. This is done for backwards compatibility reasons: in XenServer 5.5, all
users had full permissions to perform any task on the pool.
As a result, if you are upgrading from XenServer 5.5, make sure you revisit the role associated with each
user account to make sure it is still appropriate.
Configuring Active Directory authentication
XenServer supports use of Active Directory servers using Windows 2003 or later.
Active Directory authentication for a XenServer host requires that the same DNS servers are used for
both the Active Directory server (configured to allow for interoperability) and the XenServer host. In some