DNS - SRV records for Active Directory

SRV records are the important elements for Active Directory to function properly. In this session, just a quick share on What SRV records used for Active Directory:

_msdcs
This is a Microsoft-specific subdomain that stores SRV records for domain controllers with roles in AD. These roles include domain controllers, global catalog servers, and primary domain controller emulators.

_sitesThis contains records for domain controllers based on site. Microsoft Clients like Windows 2000/XP/Vista can use this record to locate domain controllers and global catalog servers that are in their site, so that they can avoid using services across the WAN.

_tcp
This contains domain controllers in the AD domain. If windows clients need to find a DC in a specific site, they will look here. The TCP protocol will be used to request the information.

_udp
Kerberos clients can use UDP port 88 to request tickets and port 464 for password changes.

DomainDnsZones
Zone information that should be replicated to all DCs in the domain that have the DNS service installed.

ForestDnsZones
Zone information that should be replicated to all DCs in the forest that have the DNS service installed.

Use nslookup to query for SRV service location records, you should:

NOTE: you will need to have reverse lookup zone setup

Type nslookup and then press Enter.
Type set type=all and then press Enter.
Type ldap.tcp.dc._msdcs.domainname and then press Enter.
Repeat this process for as many SRV records as you want to confirm.