In this guide, we will walk you through the process of fixing the 'The target principal name is incorrect' SQL error. This error can occur when trying to establish a connection to a SQL Server instance, and it is related to the Kerberos authentication protocol. We will provide step-by-step instructions on how to resolve this issue, as well as an FAQ section to address common questions.
Table of Contents
Understanding the Error
Before we dive into the solution, it's essential to understand the root cause of the error. The 'target principal name is incorrect' error typically occurs when the Service Principal Name (SPN) for the SQL Server instance is not registered correctly, or there are duplicate SPNs in the Active Directory.
An SPN is a unique identifier that is associated with a service running on a server. The Kerberos authentication protocol uses SPNs to authenticate a service and establish a secure connection.
For more information on SPNs and Kerberos authentication, refer to the following Microsoft documentation:
Step-by-Step Solution
Here's a step-by-step guide on how to fix the 'The target principal name is incorrect' SQL error:
Step 1: Identify the SQL Server Instance SPN
First, you need to identify the SPN for the SQL Server instance you're trying to connect to. You can do this by running the following command in the command prompt:
setspn -L <SQL Server Service Account>
Replace <SQL Server Service Account> with the actual service account that the SQL Server instance is running under.
Step 2: Check for Duplicate SPNs
Next, you need to check if there are any duplicate SPNs in the Active Directory. You can do this by running the following command in the command prompt:
setspn -X
This command will display a list of all duplicate SPNs, if any are present.
Step 3: Remove Duplicate SPNs
If there are any duplicate SPNs, you need to remove them. To do this, run the following command in the command prompt:
setspn -D <Duplicate SPN> <Service Account>
Replace <Duplicate SPN> with the actual duplicate SPN and <Service Account> with the associated service account.
Step 4: Register the Correct SPN
If the SPN for the SQL Server instance is not registered correctly, you need to register it. To do this, run the following command in the command prompt:
setspn -A MSSQLSvc/<Server Name>:<Port> <SQL Server Service Account>
Replace <Server Name> with the actual server name, <Port> with the SQL Server instance port number, and <SQL Server Service Account> with the service account that the SQL Server instance is running under.
Step 5: Restart the SQL Server Service
After registering the correct SPN, you need to restart the SQL Server service for the changes to take effect. You can do this by either restarting the service in the SQL Server Configuration Manager or by running the following commands in the command prompt:
net stop MSSQLSERVER
net start MSSQLSERVER
Replace MSSQLSERVER with the actual SQL Server instance name if it's a named instance.
Now, you should be able to establish a connection to the SQL Server instance without encountering the 'The target principal name is incorrect' error.
FAQ
1. What is Kerberos authentication?
Kerberos authentication is a network authentication protocol that uses secret-key cryptography to securely authenticate users and services over a non-secure network.
2. What is an SPN?
A Service Principal Name (SPN) is a unique identifier that is associated with a service running on a server. The Kerberos authentication protocol uses SPNs to authenticate a service and establish a secure connection.
3. How can I find the SQL Server Service Account?
You can find the SQL Server Service Account by checking the SQL Server Configuration Manager, under the "SQL Server Services" section.
4. Can I have multiple SPNs for a single SQL Server instance?
Yes, you can have multiple SPNs for a single SQL Server instance if it's listening on multiple ports or has multiple IP addresses.
5. Do I need to restart the SQL Server service after registering the correct SPN?
Yes, you need to restart the SQL Server service after registering the correct SPN for the changes to take effect.
Related Links
- Microsoft: Register a Service Principal Name for Kerberos Connections
- Troubleshooting Kerberos Delegation
- Using Kerberos with SQL Server
Now you have a comprehensive guide on how to fix the 'The target principal name is incorrect' SQL error. Follow the step-by-step solution provided in this guide to resolve the issue and establish a secure connection to your SQL Server instance.