DNS Registry Entries
Applies To: Windows Server 2008
The following registry entries are associated with DNS.
The information here is provided as a reference for use in troubleshooting or verifying that the required settings are applied. We do not recommend that you directly edit the registry unless there is no other alternative. Modifications to the registry are not validated by the registry editor or by Windows before they are applied, and as a result, incorrect values can be stored. This can result in unrecoverable errors in the system. When possible, modify settings though the use of policy settings or through dedicated management tools, such as the DNS snap-in for the Microsoft Management Console (MMC), to accomplish tasks, rather than editing the registry directly. If you must edit the registry, use extreme caution.
Note
In Windows Server 2003 and Windows Server 2008, the location in the registry of the settings relating to DNS zones is different from the location used in Windows 2000 Server.
In Windows 2000 Server, the location is:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Zones
In Windows Server 2003 and Windows Server 2008, the location is:
HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\CurrentVersion\DNS Server\Zones
DNS\Parameters
The following registry entries are located under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters.
EDNSCacheTimeout
Registry path
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters
Version
Windows Server 2003 and Windows Server 2008
By default, the DNS server includes option (OPT) resource records indicating its User Datagram Protocol (UDP) maximum in responses to queries containing OPT resource records. The value of the registry key EDNSCacheTimeout determines how long the DNS server will keep information about the Extension Mechanisms for DNS (EDNS) versions supported by other DNS servers that have responded to a query with a OPT resource record. The value for the registry key is specified in seconds between 3,600 (1 hour) and 15,724,800 (182 days).
EnableDirectoryPartitions
Registry path
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters
Version
Windows Server 2003 and Windows Server 2008
If you do not want the default DNS application directory partitions to be created automatically, you must disable the EnableDirectoryPartitions registry key. The values for this key are 0x0 (disable) and 0x1 (enable).
EnableEDNSProbes
Registry path
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters
Version
Windows Server 2003 and Windows Server 2008
The registry entry EnableEDNSProbes enables or disables the EDNS0 response for the DNS Server service. To configure the DNS server to include an OPT resource record only in response to EDNS0 requests containing OPT resource records, set the registry entry to a value of 0x1 (DWORD). In Windows Server 2003 and Windows Server 2008, this setting is enabled by default. Setting the value to 0x0 (DWORD) will disable the feature.
MaximumUdpPacketSize
Registry path
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters
Version
Windows Server 2003 and Windows Server 2008
The registry entry MaximumUdpPacketSize specifies the maximum UDP packet size advertised by the DNS server. The default value is 1,280 bytes. The value must be between 512 and 16,384 in decimal format (200 and 4,000 in hexadecimal format). UDP packets must travel through devices other than UDP hosts, such as routers, and some of these devices might not support UDP packets larger than 512 bytes. Determine the maximum UDP packet length that is supported by all network devices, along with the path’s Maximum Transmission Unit (MTU), before you configure this registry setting.
RoundRobin
Registry path
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters
Version
Windows Server 2003 and Windows Server 2008
By default, DNS will perform round-robin rotation for all resource record types. The default setting for round-robin rotation is contained in the registry entry RoundRobin (REG_DWORD). By default, this entry’s value is 1, rotating all RR types except those listed in the DoNotRoundRobinTypes registry entry. If the value of RoundRobin is set to 0, then no resource record types will be round-robin rotated.
DoNotRoundRobinTypes
Registry path
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Parameters
Version
Windows Server 2003 and Windows Server 2008
By default, DNS will perform round-robin rotation for all resource record types. You can specify that certain resource record types are not to be round-robin rotated in the registry. The registry entry DoNotRoundRobinTypes (REG_SZ) allows a string value to be entered containing a list of resource record types. By modifying this entry, you turn off round-robin rotation for specified resource record types. For example, to prevent round-robin rotation for A, PTR, SRV, and NS record types, you would enter the following value for the registry entry: a ptr srv ns.
DNSCache\Parameters
The following registry entries are located under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters.
AlternateComputerNames
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters
Version
Windows Server 2003 and Windows Server 2008
The AlternateComputerNames registry entry specifies a list of alternate fully qualified domain names (FQDNs) for the computer. When the DNS Client service registers the host address (A) and pointer (PTR) resource records for the computer, it will also register the FQDNs specified in this key. This key is used by the Netdom.exe utility and is not typically modified by administrators.
RegistrationRefreshInterval
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters
Version
Windows Server 2003 and Windows Server 2008
The RegistrationRefreshInterval registry entry specifies how often the DNS Client service will register the A DNS resource records for its host computer. The value for this registry key is specified in seconds.
UpdateTopLevelDomainZones
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters
Version
Windows Server 2003 and Windows Server 2008
Computers running Windows Vista, Windows XP, Windows 2000 with Service Pack 4 (SP4), Windows Server 2003, and Windows Server 2008 never try to dynamically update the root,“ ”., zone.
The domain members and domain controllers in a domain with a single-label DNS name usually need to dynamically register DNS records in a single-label DNS zone that matches the DNS name of the domain. If an Active Directory forest root has a single-label DNS name, all domain controllers in the forest usually need to dynamically register DNS records in a single-label DNS zone that matches the DNS name of the forest root.
By default, DNS clients running Windows Vista, Windows XP, Windows 2000 Service Pack 4 (SP4), and Windows Server 2003 do not attempt dynamic updates of any single-label DNS zone (.com, .net, .org, corp, for example). To enable these clients to attempt dynamic updates of a single-label DNS zones, set the UpdateTopLevelDomainZones (REG_DWORD) registry value to 0x1.
These configuration changes should be applied to all domain controllers and members of an Active Directory domain with single-label DNS names. If a domain with a single-level domain name is a forest root, these configuration changes should be applied to all of the domain controllers in the forest, unless the separate zones _msdcs. forest name, _sites. forest name, _tcp. forest name and _udp. forest name are delegated from the forest name zone. You must restart the computer for the UpdateTopLevelDomainZones registry edit to take effect.
Tcpip\Parameters
The following registry entries are located under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters.
RegistrationEnabled
(This registry entry is a global setting.)
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version
Windows Server 2003 and Windows Server 2008
The RegistrationEnabled registry entry specifies that the DNS Client service should register all of the network connections of a computer in DNS. This is a global setting that is applied to all interfaces on a computer. If you need to apply this setting to an individual interface, see the registry entry for HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters \interfaces\[interfaceGUID}.
SearchList
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Version
Windows Server 2003 and Windows Server 2008
The SearchList registry entry specifies the DNS suffix search list for the network connection used by the computer. For DNS clients, the DNS suffix search list extends or revises their DNS search capabilities. By adding additional suffixes to the list, the DNS client searches for short, unqualified computer names in more than one specified DNS domain. Then, if a DNS query fails, the DNS Client service can use this list to append other name suffix endings to the original name query and then repeat DNS queries to the DNS server for these alternate FQDNs. When the suffix search list is empty or unspecified, the primary DNS suffix of the computer is appended to short unqualified names, and a DNS query is used to resolve the resultant FQDN. If this query fails, the computer can try additional queries for alternate FQDNs by appending any connection-specific DNS suffix configured for network connections.
Interfaces\{interfaceGUID}
The following registry entries are located under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{interfaceGUID}.
NameServer
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{interfaceGUID}
Version
Windows Server 2003 and Windows Server 2008
The NameServer registry entry specifies the IP address of the DNS server that is used by the network connection of the computer.
RegistrationEnabled
(This is an interface-specific registry setting.)
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{interfaceGUID}
Version
Windows Server 2003 and Windows Server 2008
The RegistrationEnabled registry entry specifies that the DNS Client service should register the computer’s network connection in DNS. This entry is interface-specific and can be set on any interfaces on a computer. The {interfaceGUID} portion of the registry path determines to which interface the setting is applied.
There is a global version of this setting that is applied to all interfaces. Information about this setting can be found under the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\RegistrationEnabled.