Introduction to Active Directory

Active Directory Domain Services is Microsoft’s product for enterprise identity management. It contains multiple services such LDAP (database), Kerberos (authentication), Group Object Policies (access control and policy), DNS and more. Even though it has official support only on Microsoft Windows, SSSD provides seamless integration of Linux clients with Active Directory through the ad provider, including automatic SID to uid/gid translation.

The following features are supported in SSSD Active Directory integration:

  • Full support of Active Directory users and groups

  • Kerberos authentication

  • Access control via Group Policy Objects

  • Auto-discovery of of trusted domains (subdomains in SSSD terminology)

  • Auto-discovery of Active Directory site and forest

  • Automatic SID to uid and gid translation

  • Dynamic DNS records updates

  • No POSIX attributes are required on Active Directory objects

  • ID views to support migration effort

  • Automount maps and sudo rules support

  • Support for offline authentication

  • … and more


There are multiple ways to join a host into an Active Directory domain. We recommend using realmd which provides automatic domain discovery and enrollment. It is also possible to perform required steps manually.

If you want to avoid enrolling to the Active Directory domain explicitly, you may also use the ldap provider (LDAP provider with AD domain). This requires deeper understanding of SSSD configuration and does not provide all the features and benefits of the ad provider therefore it is not generally recommended.

If you need to manage large numbers of both Windows and Linux machines, you may want to consider using FreeIPA for Linux systems and establish a trust between FreeIPA and Active Directory domains. This will keep all the benefits of direct Active Directory integration but also grants you better control over the Linux system through Linux-specific identity management product. Visit Introduction to FreeIPA for more information.