Module 10: Troubleshooting AD DS,

DNS, and Replication Issues

Module Overview

• Troubleshooting Active Directory Domain Services

• Troubleshooting DNS Integration with AD DS

• Troubleshooting AD DS Replication

Lesson 1: Troubleshooting Active Directory Domain Services

• Introduction to AD DS Troubleshooting

• Discussion: How to Troubleshoot AD DS Issues

• Troubleshooting User Access Errors

• Demonstration: Tools for Troubleshooting User Access Errors

• Troubleshooting Domain Controller Performance Issues

Introduction to AD DS Troubleshooting

AD DS troubleshooting begins when:

• Users report authentication or authorization errors

• AD DS related events appear in the Event Viewer

• Domain controller performance is degraded

• An alert is generated by a monitoring system

• Data is not being replicated between domain controllers

Discussion: How to Troubleshoot AD DS Issues

• What tools would you use?

• How would you verify that your solution worked?

Troubleshooting User Access Errors

User access errors may be the result of:

• Network access errors

• Authentication errors

• Authorization errors

To address user access errors, verify:

• Network connectivity

• Time synchronization

• Domain controller availability

• User account and user lockout settings

• Group memberships

Demonstration: Tools for Troubleshooting User Access Errors

In this demonstration, you will see how to troubleshoot user access errors using Windows tools

Troubleshooting Domain Controller Performance Issues

Most common performance issues include:

• High CPU utilization

• High network utilization

To resolve performance issues:

Identify the processes with high CPU utilization

Move applications or services to another server

Monitor application-specific network traffic

Distribute AD DS and DNS roles across multiple servers

Review and modify the replication topology

Deploy domain controllers with 64-bit hardware

Lesson 2: Troubleshooting DNS Integration with AD DS

• Overview of DNS and AD DS Troubleshooting

• Troubleshooting DNS Name Resolution

• Troubleshooting DNS Name Registration

• Troubleshooting DNS Zone Replication

Overview of DNS and AD DS Troubleshooting

Troubleshoot DNS and AD DS integration when:

• Users cannot log on to AD DS

• AD DS replication is failing

• AD DS installation fails

To troubleshoot DNS and AD DS integration, verify:

• DNS client and server configurations

• DNS name registration

• DNS zone replication

Troubleshooting DNS Name Resolution

DNS name resolution may fail due to:

• Network connectivity issues

• Client configuration errors

• DNS server availability

• Name registration or DNS replication issues

To troubleshoot DNS name resolution:

• Test network connectivity by pinging the DNS server by IP address

• Use IPconfig to examine the client configuration

• Use NSlookup to verify server availability

• Flush the DNS cache

• Use NSlookup to verify SRV records

Troubleshooting DNS Name Registration

DNS name registration may fail due to:

• Client configuration errors

• DNS server availability

• DNS zone configuration

To troubleshoot DNS name registration:

• Verify that the client is configured to register in DNS

• Test DNS server availability

• Verify that the DNS zone is configured fordynamic updates

• Test DNS by using the DCDiag /Test:DNS command

• Register the SRV records by restarting the Netlogon service

Troubleshooting DNS Zone Replication

Investigate DNS zone replication issues when:

• DNS-related issues are specific to certain DNS server clients

• Zone information is not consistent on different DNS servers

• DNS server availability is not consistent

• There are DNS replication or name registration issues

Troubleshoot AD DS replication for AD DS integrated zones

To troubleshoot standard zone transfer issues:

• Verify network connectivity

• Verify primary server and secondary server configuration

• Verify Start of Authority record

• Verify zone transfer configuration

Lesson 3: Troubleshooting AD DS Replication

• AD DS Replication Requirements

• Common Replication Issues

• What Is the Repadmin Tool?

• What Is the DCDiag Tool?

• Identifying the Cause of Replication Errors

• Discussion: Troubleshooting Inter-Site AD DS Replication Issues

• Troubleshooting Distributed File Replication Issues

AD DS Replication Requirements

AD DS replication requires:

• Routable IP infrastructure

• DNS name resolution

• RPC or Simple Mail Transfer Protocol (SMTP) connectivity between domain controllers

• Kerberos v5 authentication

• Lightweight Directory Access Protocol (LDAP)connectivity to install new domain controllers

• File Replication Service or Distributed File System Replication

Common Replication Issues

Replication greatly increases network traffic

Possible causes

Replication does not finish or occur

Replication is slow

Client computersreceive a slow response

Symptom

• Sites not connected by site links• No bridgehead server in the site group

• No domain controller online in client site

• Not enough domain controllers

• Inefficient site topology and schedule

• Insufficient bandwidth• Incorrect site topology

What Is the Repadmin Tool?

Use the Repadmin command-line tool to:

• View and manually create the replication topology

• Force replication events between domain controllers

• View the replication metadata

Syntax: repadmin command arguments [/u:[domain\]user pw:{password|*}]

What Is the DCDiag Tool?

Use the Dcdiag command-line tool to:

• Analyze the state of a domain controller, and report any problems

• Perform a series of tests to verify different system areas

Syntax: dcdiag command arguments [/v /f:LogFile /ferr:ErrLog ]

Identifying the Cause of Replication Errors

• System monitor NTDS counters

Testing method

Sites are notconnected bysite links

No bridgehead server in the site

Inefficient site topology and schedule

Possible causes

• Dcdiag /test:Topology

• Repadmin /bridgeheads

• Repadmin /latency

No domain controlleronline in the site

• Dcdiag /test:Replication• Dcdiag /test:Connectivity

Not enough domain controllers

Incorrect site topology

• AD DS Sites and Services• Repadmin /latency• V Dcdiag /test:Intersite

Discussion: Troubleshooting Inter-Site AD DS Replication Issues

• What steps would you take to troubleshoot an AD DS replication issue?

• How would you verify that your solution worked?

Troubleshooting Distributed File Replication Issues

• Windows Server 2008 uses FRS or DFSR to replicate the SYSVOL directory between domain controllers

• Both FRS and DFSR require LDAP and RPC connectivity between domain controllers

• Use Ntfrsutl and FRSDiag to troubleshoot FRS replication

• Use DFSRAdmin to troubleshoot DFRS replication

Lab: Troubleshooting AD DS, DNS, and Replication Issues

• Exercise 1: Troubleshooting Authentication and Authorization Errors

• Exercise 2: Troubleshooting the Integration of DNS and AD DS

• Exercise 3: Troubleshooting AD DS Replication

Logon information

Virtual machine NYC-DC1, NYC-CL1

User name Administrator

Password Pa$$w0rd

Estimated time: 60 minutes

Lab Review

• If the Los Angeles office was configured as a separate site, what additional steps would you need to take to troubleshoot Trouble Ticket #5?

• What AD DS troubleshooting issues do you think you will need to deal with most often in your organization?

Module Review and Takeaways

• Considerations

• Tools

• Review questions