Active Directory Domain Services Support

Communications Server 2007 R2

Microsoft Office Communications Server 2007 and Microsoft Office Communications Server 2007 R2 will reach end of support on January 9, 2018. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.


Topic Last Modified: 2016-12-01

Office Communications Server supports a single forest or multiple-tree forest as identified in Supported Active Directory Topologies. This topic identifies the operating system and other requirements for Active Directory Domain Services.

Supported Domain Names

Office Communications Server should not be installed in a domain in which the last part of the FQDN begins with a numeral. For example, xxx.yyy.4zz and aaa.bbb.1ab are both invalid names, whereas 4xx.yyy.zzz and aaa.bbb.ab1 are both valid domain names.

The FQDN of any Office Communications Server, pool, array, or Edge Server can contain only ANSI alphanumeric characters, hyphens, and underscores. Unicode characters are not supported.

Underscores are permitted, but not recommended, in FQDNs in Office Communications Server 2007 R2.

Office Communications Server and Office Communicator support only SIP URIs that conform to standard SIP grammar and that contain no escaped characters.

Office Communications Server does not support single-labeled domains. For example, a forest with a root domain named local is not supported. For details, see “Information about configuring Windows for domains with single-label DNS names” at

Supported Domain Controller Operating Systems

  • Windows Server 2008 R2

  • Windows Server 2008

  • Windows Server 2003 R2

  • Windows Server 2003 with no earlier than Service Pack 1 (SP1)

For details about the operating systems that are supported for Active Directory domain controllers for each version of Office Communications Server, see Supported Active Directory Environments by Office Communications Server Version.

Global catalogs are recommended in each Office Communications Server domain to optimize performance of Office Communications Servers and to ensure interdomain IM, presence, and conferencing scenarios operate properly.

Support for Read-Only Domain Controllers

Office Communications Server 2007 R2 supports Active Directory Domain Services deployments that include read-only domain controllers or read-only global catalog servers, as long as there are writable domain controllers available.

Forest and Domain Functional Level

All domains in which you deploy Office Communications Server must be raised to a domain functional level of at least Windows Server 2003. You cannot deploy Office Communications Server 2007 R2 in a Windows 2000 mixed or Windows 2000 native domain. All forests in which you deploy Office Communications Server must be raised to a forest functional level of at least Windows Server 2003.

To change your domain or forest functional level, see “Raising domain and forest functional levels” in the Windows documentation at

You must run Active Directory preparation steps on a computer running Windows Server 2003 with SP2, Windows Server 2003 R2 with SP2, or Windows Server 2008. You cannot run Active Directory preparation on a computer running Windows 2000 Server or earlier, or on a computer running any client version of the Windows operating system. For details about preparing Active Directory Domain Services for Office Communications Server 2007 R2, see Office Communications Server 2007 R2 Active Directory Guide in the Deployment documentation.


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