Providing Reverse Lookup

Applies To: Windows Server 2008

In most Domain Name System (DNS) lookups, clients typically perform a forward lookup, which is a search based on the DNS name of another computer as the name is stored in a host (A or AAAA) resource record. This type of query expects an IP address as the resource data for the answered response.

DNS also provides a reverse lookup process, in which clients use a known IP address during a name query and look up a computer name based on its address. A reverse lookup takes the form of a question, such as "Can you tell me the DNS name of the computer that uses the IP address"

To provide this answer, two special domains, and, are defined in the DNS standards and reserved in the Internet DNS namespace to support reverse queries. The domain provides reverse-lookup support for IP version 4 (IPv4)-based IP addresses, while the domain provides reverse lookup for IP version 6 (IPv6)-based IP addresses.

To make it possible for DNS clients to perform a reverse lookup for a host, you perform two steps:

  1. Create a reverse lookup zone that corresponds to the subnet network address of the host.

  2. In the reverse lookup zone, add a pointer (PTR) resource record that maps the host IP address to the host name.

After you create the zone, you manage it much as you would a forward lookup zone. Also, like a forward lookup zone, a reverse lookup zone can be integrated with Active Directory Domain Services (AD DS), and it can be mirrored by secondary and stub zones. You can also delegate a reverse lookup zone, and you can configure a reverse lookup zone to accept dynamic updates, which reduces the need to add and manage pointer (PTR) resource records directly.

This section includes the following tasks for providing reverse lookup: