Active Directory DNS Service (SRV) Resource Records (RR)

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Active Directory DNS Service (SRV) Resource
Records (RR)
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props

• http//www.petri.co.il/active_directory_srv_record
  s.htm

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AD built on DNS

• Windows 2000/2003 domains rely heavily on DNS
  entries

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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.

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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 ???

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Dynamic update on DNS zones W2Kx automatically
creates

• _ldap._tcp.ltDNSDomainNamegt
• _ldap._tcp.ltSiteNamegt._sites.ltDNSDomainNamegt
• _ldap._tcp.pdc._ms-dcs.ltDNSDomainNamegt
• _ldap._tcp.gc._msdcs.ltDNSTreeNamegt
• _ldap._tcp. ._sites.gc._msdcs.ltDNSTreeNamegt
• _ldap._tcp.ltDomainGuidgt.domains._msdcs.ltDNSTreeNam
  egt
• ltDNSDomainNamegt

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_ldap._tcp.ltDNSDomainNamegt

• Enables a client to locate a W2K domain
  controller in the domain named by
  ltDNSDomainNamegt. A client searching for a domain
  controller in the domain dpetri.net would query
  the DNS server for _ldap._tcp.dpetri.net.

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_ldap._tcp.ltSiteNamegt._sites.ltDNSDomainNamegt

• 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).

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_ldap._tcp.pdc._ms-dcs.ltDNSDomainNamegt

• 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.

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_ldap._tcp.gc._msdcs.ltDNSTreeNamegt

• 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.

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_ldap._tcp. ._sites.gc._msdcs.ltDNSTreeNamegt

• Enables a client to find a GC server in the
  specified site (e.g., _ldap._tcp.lab._sites.gc._ms
  dcs.dpetri.net).

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_ldap._tcp.ltDomainGuidgt.domains._msdcs.ltDNSTreeNam
egt

• Enables a client to find a domain controller in a
  domain based on the domain controllers globally
  unique ID. A GUID is a 128-bit (8 byte) number
  that generates automatically for referencing
  Active Directory objects.

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ltDNSDomainNamegt

• Enables a client to find a domain controller
  through a normal Host record.

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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\System
  32\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.

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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