RoundRobin

HKLM\SYSTEM\CurrentControlSet\Services\DNS\Parameters

Data type

Range

Default value

REG_DWORD

0 | 1

1

Description

Determines the order in which the Domain Name System (DNS) server returns A (address) records when it has multiple A records for the same name.

Value

Meaning

0

The DNS server returns the A records in a fixed, file load order.

1

The DNS server rotates among the A records it returns for a given name. Rotating helps to balance the load placed on each connection to the named server.

Change method

To change the value of this entry, use the DNS console. Right-click the server name, click Properties, click the Advanced tab. This entry corresponds to the Enable round robin option. Or, use Dnscmd.exe, a tool included with the Windows 2000 Support Tools. Using either method, your changes are effective immediately; you do not have to restart the DNS server.

Activation method

DNS reads its registry entries only when it starts. If you change the value of this entry by editing the registry, the changes are not effective until you restart the DNS server.

Note Image Note

The order in which A records are returned depends on the value of this entry and of the LocalNetPriority entry, as follows:

  • When both are set to 1 (or when RoundRobin does not appear in the registry), the DNS server rotates among the A records it returns in local net priority order, that is, in order of their similarity to the IP address of the querying client.

  • If the value of RoundRobin is 0 and the value of LocalNetPriority is 1, the DNS server returns the records in local net priority order. It does not rotate among available addresses.

  • If the value of RoundRobin is 1 and the value of LocalNetPriority is 0, the DNS server rotates among the available records in the order in which the records were added to the database.

  • If the values of RoundRobin and LocalNetPriority are 0, the DNS server returns the records in the order in which they were added to the database. It does not attempt to sort them or to rotate among them.

Related Entries

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LocalNetPriority

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ForwardingTimeout

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RecursionRetry

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