Host is active, but unable to classify - Discovery Error - CI still updated

[Steven Morse]

Hi

I have a large amount of discovery errors and I am trying to resolve the larger groups with the same error.

I have a huge amount of 'Host is active, but unable to classify' errors. I searched for the effected IPs in the CMDB to see if Discovery was still successful despite the error - in many cases it was. 

Therefore I am receiving this error message despite Discovery finding and populating the CI at the effected IP. 

I am looking to establish 

a) why this happens?

b) how I can remediate/prevent these error moving forward

Thanks

[sachin45]

Hi @Steven Morse ,

Based on your update on the question , I think I can provide some insights into the issue you're encountering with the "Host is active, but unable to classify" errors.

I’ll address both of the questions you raised:

a) Why does this happen?

From your description, it sounds like the Discovery process is successfully detecting the devices and updating the CMDB, even though they aren't classified. This typically occurs under credential-less discovery. Here’s why:

1. Credential-less Discovery:

   • When Discovery is performed without using credentials (i.e., credential-less discovery), it relies on techniques like Reverse DNS and the NMAP protocol to detect devices on the network. This allows Discovery to identify that a host is active and populate the CI in the CMDB. However, it doesn’t have the full access to the device's detailed data, which is necessary for proper classification.
   • In credential-less discovery, no exploration probes are triggered, meaning the system does not perform a deep dive into the device to gather all the required information for classification. As a result, only partial information (like the device's hostname or IP address) is populated in the CMDB, but it lacks detailed attributes like the serial number, manufacturer, or model.

2. Missing or Incorrect Credentials:

   • If credentials are not available or incorrect, Discovery may be able to detect the device but cannot classify it properly. In such cases, the device is detected, but the classification process fails, resulting in the error you're seeing. For classification to succeed, the classifier needs to be active, and the correct credentials need to be available for the device.

3. Classifier Misconfiguration:

   • If the device classifier is not properly configured or is inactive for the specific type of device, it may be unable to classify the device, even though Discovery detects it successfully. The classifier matches devices to specific CI classes based on their attributes, and if there are gaps or issues with the classifier, classification will fail.

4. Device Not Fully Explored:

   • When using credential-less discovery, only basic attributes are captured because no deeper exploration is triggered. For devices with limited exposure (due to missing credentials), they are added to the CMDB, but without the complete set of classification data.

b) How can I remediate/prevent these errors moving forward?

Here are some steps to help prevent and resolve this issue:

1. Enable and Use Credentials for Discovery:

   • To ensure that the device is properly classified, it's essential to use valid credentials for the devices in question. If you're using SNMP, SSH, WMI, or other protocols, ensure that the correct credentials are configured in the Discovery process. This will allow Discovery to gather more comprehensive data and successfully classify the devices.
   • Credentials also allow deeper exploration into the devices (e.g., serial numbers, hardware details, OS version), which is necessary for proper classification.

2. Check Classifier Configuration:

   • Make sure the device classifiers are properly configured and active for the types of devices you're discovering. If you're finding that certain devices are being detected but not classified, review the classification rules to ensure they cover the device types in your network. You may need to update the classifier patterns or add new ones to accommodate specific devices.

3. Use Credential-less Discovery with Caution:

   • If you must use credential-less discovery (for example, when credentials cannot be applied to certain devices), understand that partial information will be captured. To improve classification, you can perform a follow-up discovery using credentials once the device is detected and identified. Alternatively, you can enhance the patterns used in the credential-less discovery to gather more useful data, though this may still not be as comprehensive as credential-based discovery.

4. Review Discovery Logs:

   • Analyze the discovery logs to understand more about why the classification failed. Logs often contain details about missing attributes or errors in the classification process that can help pinpoint the root cause.

5. Handle Duplicates and Conflicts in the CMDB:

   • If devices are being discovered successfully but are not classified properly, it's also a good idea to check the CMDB for duplicate entries or conflicting CIs. Sometimes, the same device might get populated multiple times under different classifications, which can cause confusion in your data and lead to errors.

6. Perform Targeted Discovery Tests:

   • For devices that frequently cause these errors, run targeted discovery tests on them individually. This can help you confirm if there’s an issue with the credentials, classifier, or something else preventing proper classification. Doing this in isolation can help you troubleshoot the root cause without the interference of other devices.

7. Regularly Review and Update Discovery Settings:

   • As your network evolves and new devices are added, regularly update your discovery settings, classifiers, and credential configurations to ensure that the Discovery process is accurate and complete. This is especially important if you’re adding new device types or changing network configurations.

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By following these steps, you should be able to significantly reduce the number of "Host is active, but unable to classify" errors and ensure that devices are classified properly when they are detected by Discovery.

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