This document discusses integrating FreeIPA with Active Directory through cross-forest trusts. It describes how FreeIPA provides identity management similar to Active Directory and can be configured to trust an Active Directory domain. This allows FreeIPA and Active Directory users to access each other's services. The document also discusses how legacy systems without SSSD can still access user and group information by querying a compatibility LDAP tree on the FreeIPA server. It concludes by noting that FreeIPA passed over 100 compatibility tests with Windows Server 2012.