No Dynamic Updates on a Classless Reverse Lookup Zone


Domain Name System (DNS) dynamic updates of Pointer (PTR) records cannot be performed on a classless reverse lookup zone.


To create PTR records in a reverse lookup zone, follow these steps on the parent and child DNS servers:

On the Parent DNS Server

  1. Create a non-subnetted reverse lookup zone. For example, if you have subnetted your network into two subnets, and, and you want to create reverse lookup zones for the first subnet, create a reverse lookup zone for The zone name is
  2. Right-click the new zone, and then click New Delegation.
  3. Click Next. In the Delegated Domain box, type 0/25, where 0 is the subnet address and 25 is the number of bits used for subnetting.
  4. Click Next. Add the child DNS server's name and address when you are prompted, click OK, and then click Finish.
  5. Right-click the parent zone (not the delegated zone), and then click New Alias.
  6. Type the alias (the last octet of the IP address). For example, type 1 for a host with an IP address of
  7. In the Fully Qualified Domain Name box, type the CNAME value. For example, type
    1.0/, and then click OK.
  8. Repeat steps 6 through 8 for every host that needs to be added.

On the Child DNS Server

  1. On the child DNS server, create a subnetted reverse lookup zone. For example, 0/
  2. Create PTR records for every host under the new zone. In the Host IP Number box, type the last octet of the IP address. In the Host Name box, type the fully qualified domain name of the host.
NOTE: This example is for a subnetted class C network. For networks that use other class addresses, make the appropriate changes. For more information about subnetted reverse lookup zones see the following article in the Microsoft Knowledge Base:
174419 How to Configure a Subnetted Reverse Lookup Zone on Windows NT


This behavior is by design. It is not possible to perform dynamic updates of DNS records on a classless reverse lookup zone.


in  Adding a Reverse Lookup Zone

Configuring and Delegating a Classless In-addr .arpa Reverse Lookup Zone


Dynamic update does not work with classless in - zones. If you need to dynamically update PTR resource records, do not use classless zones.

For Windows Server 2008 R2 see article: Adding a resource record to a reverse lookup zone


Artikelnummer: 253575 – Letzte Überarbeitung: 31.03.2014 – Revision: 1