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Active Directory DNS Service (SRV) Resource Records (RR). ~props~. http://www.petri.co.il/active_directory_srv_records.htm. AD built on DNS. Windows 2000/2003 domains rely heavily on DNS entries. Service Location (SRV) resource records.
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Active Directory DNS Service (SRV) Resource Records (RR) AD DNS SRV RRs
~props~ • http://www.petri.co.il/active_directory_srv_records.htm AD DNS SRV RRs
AD built on DNS • Windows 2000/2003 domains rely heavily on DNS entries AD DNS SRV RRs
Service Location (SRV) resource records • In order for Active Directory to function properly, DNS servers must provide support for Service Location (SRV) resource records described in RFC 2052, A DNS RR for specifying the location of services (DNS SRV). • SRV resource records map the name of a service to the name of a server offering that service. • Active Directory clients and domain controllers use SRV records to determine the IP addresses of domain controllers. AD DNS SRV RRs
Dynamic DNS - DDNS • Although not a technical requirement of Active Directory, it is highly recommended that DNS servers provide support for DNS dynamic updates described in RFC 2136, Observations on the use of Components of the Class A Address Space within the Internet. • Windows 2000/2003 DNS • Windows NT Server 4.0 SP 4 and later supports SRV resource records • BIND version ??? AD DNS SRV RRs
Dynamic update on DNS zones; W2Kx automatically creates: • _ldap._tcp.<DNSDomainName> • _ldap._tcp.<SiteName>._sites.<DNSDomainName> • _ldap._tcp.pdc._ms-dcs.<DNSDomainName> • _ldap._tcp.gc._msdcs.<DNSTreeName> • _ldap._tcp. ._sites.gc._msdcs.<DNSTreeName> • _ldap._tcp.<DomainGuid>.domains._msdcs.<DNSTreeName> • <DNSDomainName> AD DNS SRV RRs
_ldap._tcp.<DNSDomainName> • Enables a client to locate a W2K domain controller in the domain named by <DNSDomainName>. A client searching for a domain controller in the domain dpetri.net would query the DNS server for _ldap._tcp.dpetri.net. AD DNS SRV RRs
_ldap._tcp.<SiteName>._sites.<DNSDomainName> • Enables a client to find a W2K domain controller in the domain and site specified (e.g., _ldap._tcp.lab._sites.dpetri.net for a domain controller in the Lab site of dpetri.net). AD DNS SRV RRs
_ldap._tcp.pdc._ms-dcs.<DNSDomainName> • Enables a client to find the PDC flexible single master object (FSMO) role holder of a mixed-mode domain. Only the PDC of the domain registers this record. AD DNS SRV RRs
_ldap._tcp.gc._msdcs.<DNSTreeName> • Enables a client to find a Global Catalog (GC) server. Only domain controllers serving as GC servers for the tree will register this name. If a server ceases to be a GC server, the server will deregister the record. AD DNS SRV RRs
_ldap._tcp. ._sites.gc._msdcs.<DNSTreeName> • Enables a client to find a GC server in the specified site (e.g., _ldap._tcp.lab._sites.gc._msdcs.dpetri.net). AD DNS SRV RRs
_ldap._tcp.<DomainGuid>.domains._msdcs.<DNSTreeName> • Enables a client to find a domain controller in a domain based on the domain controller’s globally unique ID. A GUID is a 128-bit (8 byte) number that generates automatically for referencing Active Directory objects. AD DNS SRV RRs
<DNSDomainName> • Enables a client to find a domain controller through a normal Host record. AD DNS SRV RRs
DNS with SRV but not dynamic support? • A DNS server that supports SRV records but does not support dynamic update must be updated with the contents of the Netlogon.dns file created by the Active Directory Installation wizard while promoting a Windows 2000 Server to a domain controller. • After running DCPROMO, A text file containing the appropriate DNS resource records for the domain controller is created. The file called Netlogon.dns is created in the %systemroot%\System32\config folder and contains all the records needed to register the resource records of the domain controller. Netlogon.dns is used by the Windows 2000 NetLogon service and to support Active Directory for non-Windows 2000 DNS servers. • If you are using a DNS server that supports the SRV resource record but does not support dynamic updates (such as a UNIX-based DNS server or a Windows NT Server 4.0 DNS server), you can import the records in Netlogon.dns into the appropriate primary zone file to manually configure the primary zone on that server to support Active Directory. AD DNS SRV RRs
Links • Windows 2000 Deployment Planning Guide • Troubleshooting Common Active Directory Setup Issues in Windows 2000 – 260371 • Setting Up the Domain Name System for Active Directory – 237675 • Information About Configuring Windows 2000 for Domains with Single-Label DNS Names - 300684 AD DNS SRV RRs