Data type Range Default value
REG_DWORD 0 | 1 0


Enables and disables automatic reverse zones, an optimizing feature of DNS. When automatic reverse zones is enabled, DNS automatically creates three reverse lookup zones.

Reverse lookup zones enable the DNS server to be authoritative, that is, to know the answer in advance and to respond immediately to the most common name queries, eliminating unnecessary recursive queries. In accordance with pertinent RFCs, by default, the DNS server is authoritative for three reverse lookup zones:

Value Meaning
0 The automatic reverse zones feature is enabled. The DNS server automatically creates three reverse lookup zones.
1 Disables automatic reverse zones. The DNS server does not create reverse lookup zones automatically.

Change method

To change the value of this entry, use Dnscmd.exe, a tool included with the Windows 2000 Support Tools, and then restart the DNS server. Please note that changing this entry is not recommended.

Activation method

Because the DNS server creates zones only when it starts, you must restart the DNS server to make changes to this entry effective, even when using Dnscmd to make the change.

Note Image Note

DNS does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry, such as Dnscmd.exe.

Caution Image Caution

Do not change the value of this entry unless instructed to by Microsoft Product Support. Using automatic reverse zones improves the performance of the DNS server. The default value is optimal for almost all DNS server configurations.