Question:

I’m seeking expert advice regarding a challenge we’re facing in our domain setup, which includes two Domain Controllers (DCs). We’ve recently added a Read-Only Domain Controller (RODC) with DNS capabilities, but we’ve noticed that the DNS records are not being updated as expected. Our DNS configuration comprises numerous zones, and while the desired DNS zone appears on the RODC post-installation, it lacks the complete set of records found on the DCs. Moreover, any new records added to the DNS do not seem to replicate to the RODC’s DNS at all.

Could you provide any insights or solutions to address this replication issue?”

Answer:

When managing a domain that includes two Domain Controllers (DCs) and a newly added Read-Only Domain Controller (RODC) with DNS capabilities, it’s crucial to ensure that DNS records are accurately replicated. However, it’s not uncommon to encounter challenges where the DNS records on the RODC are not updated as expected, despite the DNS zone being visible post-installation.

The primary function of an RODC is to provide a way to access domain resources while maintaining a higher level of security. It holds a read-only copy of the Active Directory database and DNS zones. However, this read-only nature can lead to replication issues, particularly when there are numerous DNS zones involved. If new records added to the DNS are not replicating to the RODC’s DNS, it could be due to several reasons:

1.

Replication Latency

: Replication between writable DCs and RODCs is not instantaneous and is subject to the replication schedule.

2.

DNS Configuration

: The RODC’s DNS settings might not be configured correctly to allow for proper replication.

3.

Connectivity Issues

: Network problems between the RODC and writable DCs can prevent replication.

4.

Security Permissions

: The RODC might not have the necessary permissions to receive updates from the writable DCs.

Potential Solutions

To address these replication issues, consider the following steps:

1.

Verify Replication Settings

: Ensure that the replication schedule is set appropriately for your environment and that the RODC is included in the replication topology.

2.

Check DNS Settings

: On the DNS console, confirm that the Host (A) records are pointed to the correct IP addresses of the RODC and the writable DCs.

3.

Review Security Settings

: Make sure that the RODC has the necessary permissions to replicate DNS records. This includes checking the security settings on the DNS zones.

4.

Run Diagnostic Commands

: Utilize commands like `dcdiag` and `dcdiag /test:dns /v` on the RODC to check for any issues.

5.

Disable Firewalls Temporarily

: If you have any antivirus programs or firewalls enabled, consider disabling them temporarily to rule out any interference with the replication process.

6.

Synchronize Time Settings

: Ensure that the date and time on the RODC are synchronized with the writable DCs, as incorrect time settings can cause replication failures.

Conclusion

Replication issues with RODCs can be complex and multifaceted. By methodically checking the replication settings, DNS configurations, security permissions, and network connectivity, you can identify and resolve the underlying causes of the replication problems. Remember to always maintain a secure environment by re-enabling any security software after testing and to monitor the system regularly to prevent future issues. If problems persist, consider reaching out to a specialist with experience in Active Directory and DNS configurations for further assistance.