Technical Tip: Understanding LDAP error codes

LDAP (Lightweight Directory Access Protocol) is a crucial component in network authentication, and FortiGates often utilize LDAP for user authentication and user group integration. However, LDAP operations can encounter errors, each represented by a specific error code.

1. LDAP Error 49 - Invalid Credentials.

• Meaning: The provided username and/or password for the LDAP authentication are incorrect.
• Solution: Verify the accuracy of the credentials entered. Ensure that the username and password are correctly typed and match the LDAP directory. The other reason is that the user account has expired.

2.  LDAP Error 50 - Insufficient Access Rights.

• Meaning: The authenticated user does not have the necessary permissions to perform the requested operation.
• Solution: Ensure that the user account used for LDAP authentication has the required access rights within the LDAP directory.

3.  LDAP Error 32 - No Such Object.

• Meaning: The specified object (usually a user or group) does not exist in the LDAP directory.
• Solution: Double-check the object's distinguished name (DN) or the filter criteria used to search for the object.

4. LDAP Error 53 - Unwilling to Perform.

• Meaning: The LDAP server refuses to operate.
• Solution: This error can have multiple causes, such as server misconfiguration or limitations. Investigate the server logs for more details.

5. LDAP Error 81 - Server Down.

• Meaning: The LDAP server is unavailable.
• Solution: Ensure that the LDAP server is operational and reachable from the FortiGate firewall. Check network connectivity and server status.

6. LDAP Error 82 - Local Error.

• Meaning: An error occurred on the LDAP client side, possibly due to client configuration.
• Solution: Review the LDAP client settings on the FortiGate and verify the correctness of the configuration.

7. LDAP Error 85 - Timeout.

• Meaning: The LDAP operation timed out while waiting for a response from the server.
• Solution: Check the network connectivity between the FortiGate and the LDAP server. Ensure that there are no network-related issues causing delays.

8.  LDAP Error 91 - Connect Error.

• Meaning: The FortiGate firewall was unable to establish a connection to the LDAP server.
• Solution: Verify the LDAP server address, port, and firewall rules to ensure proper connectivity.

9. LDAP Error 4 - Size Limit Exceeded.

• Meaning: The LDAP query results exceed the configured size limit.
• Solution: Adjust the LDAP query or search settings to limit the number of returned results.

10.  LDAP Error 95 - Compare False.

• Meaning: A comparison operation resulted in a 'false' response.
• Solution: Review the comparison operation and the attributes being compared for correctness.

11. LDAP Error 2 - Protocol Error.

• Meaning: A malformed LDAP request from the client.
• Solution: Ensure the client uses a supported LDAP version that the server supports.

12. LDAP Error 52 - LDAP Unavailable.

• Meaning: Indicates that the LDAP server cannot process the client's bind request.
• Solution: Ensure that the LDAP service is in a running state.

13. LDAP Error 7 - Authentication method not supported.

• Meaning: The authentication method requested by the FortiGate unit is not supported by the LDAP server.
• Solution: Ensure that Secure Connection is enabled in the FortiGate LDAP server configuration and the protocol is set to LDAPS. The CA certificate from the LDAP server must be exported and imported into the FortiGate. 

14. LDAP Error 33 - Alias Problems.

• Meaning: Indicates that it has a problem resolving an alias (e.g. alias chain too long, misconfigured alias).
• Solution: Avoid using the alias in the operation. Use the “real” DN instead of the alias DN

15. LDAP Error 34 - Invalid DN Syntax.

• Meaning: The provided DN is not grammatically valid.
• Solution: Ensure that there are no missing commas, special characters, or extra spaces between RDN components.

It is important to note that these error codes are not exclusive to FortiGate and can be encountered with other LDAP implementations as well. Always consult the FortiGate documentation and the LDAP server documentation for specific troubleshooting steps tailored to the environment.

Remember to consider security best practices while configuring LDAP authentication, such as using secure connections (LDAPS) and appropriate access controls.

Do not hesitate to reach out to Fortinet Support for assistance.