How to Fix: Why does Installation of new domain controller throws an error about used ports (88)?

When installing a new domain controller in Windows Server 2016, you may encounter an error message indicating that TCP ports required by Active Directory Domain Services are already in use on the computer. This can be frustrating, especially when only one port is in use, which is port 88. In this guide, we will walk you through the troubleshooting steps to resolve this issue.

The good news is that resolving this error does not require any complex technical expertise or extensive knowledge of Active Directory configuration. By following these simple steps, you should be able to release the used port and successfully install your new domain controller.

⚠️ Common Causes

• The primary reason for this error is that the System process is using port 88, which is required by Active Directory Domain Services. This can happen when the System process is running an outdated version of Windows or has not been properly configured.
• Another possible cause could be a misconfigured DNS server on your network, causing it to redirect requests for domain controller installation to use port 88 instead of one of the other available ports.

✅ Best Solutions to Fix It

💡 Conclusion

By following these simple steps, you should be able to resolve the error and successfully install your new domain controller. Remember to regularly check and update your DNS server configuration to avoid similar issues in the future.