Tuesday, October 18, 2016

How to verify that SRV DNS records have been created for a domain controller

The SRV record is a Domain Name System (DNS) resource record that is used to identify computers that host specific services. SRV resource records are used to locate domain controllers for Active Directory. To verify SRV locator resource records for a domain controller, use one of the following methods.

DNS Manager

After you install Active Directory on a server running the Microsoft DNS service, you can use the DNS Management Console to verify that the appropriate zones and resource records are created for each DNS zone.

Active Directory creates its SRV records in the following folders, where Domain_Name is the name of your domain:
Forward Lookup Zones/Domain_Name/_msdcs/dc/_sites/Default-First-Site-Name/_tcp Forward Lookup Zones/Domain_Name/_msdcs/dc/_tcp

In these locations, an SRV record should appear for the following services:


If you are using non-Microsoft DNS servers to support Active Directory, you can verify SRV locator resource records by viewing Netlogon.dns. Netlogon.dns is located in the %systemroot%\System32\Config folder. You can use a text editor, such as Microsoft Notepad, to view this file.

The first record in the file is the domain controller's Lightweight Directory Access Protocol (LDAP) SRV record. This record should appear similar to the following:


Nslookup is a command-line tool that displays information you can use to diagnose Domain Name System (DNS) infrastructure.
To use Nslookup to verify the SRV records, follow these steps:
  1. On your DNS, click Start, and then click Run.
  2. In the Open box, type cmd.
  3. Type nslookup, and then press ENTER.
  4. Type set type=all, and then press ENTER.
  5. Type _ldap._tcp.dc._msdcs.Domain_Name, where Domain_Name is the name of your domain, and then press ENTER.
Nslookup returns one or more SRV service location records that appear in the following format, where Server_Name is the host name of a domain controller, and where Domain_Name is the domain the domain controller belongs to, and Server_IP_Address is the domain controller's Internet Protocol (IP) address:
Server: localhost
SRV service location:
 priority = 0
 weight  = 100
 port  = 389
 srv hostname = Server_Name.Domain_NameServer_Name.Domain_Name  internet address = Server_IP_Address