What is the process for a server selecting the Active Directory domain controller? When a server requires a Domain Controller , what are the steps leading to a Domain Controller decision. I’m interested to understand – to troubleshoot some Clustering setup issues.
These are the steps followed by a server communicating with Domain Controllers
STEP 1 : Execute a Query against the Primary DNS server , returning each Domain Controller (DC) in the domain
nslookup -type=srv _ldap._tcp.mydomain.net
STEP 2 : The server elects the first DC in DNS list using LDAP to connect
STEP 3 : Is the chosen DC in the same AD site site as the member server ? Based on information configured in AD sites
if yes –> server starts using the DC
if no —> DC will communicate to server member its site
–> server will send new DNS query for the DC list for it’s own site
–> Member selects the first DC in the DNS list , using LDAP to connect
__>if no DC on local site – connect to any DC in the domain
Note:cache local site name in registry to speed up future request
Useful commands using the nltest tool . The nltest tool is available if the AD DS or AD LDS server role is installed.
–List trusted domains
nltest /trusted_domains
–List DCs in a specific domain
nltest /dclist:mydomain
–Return the AD site of the current server
nltest /dsgetsite
–List every DC registered the site name
nslookup -type=srv _ldap._tcp.mydomain.net
Author: Rambler
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