Troubleshooting

Use the troubleshooting techniques described here to respond to errors and performance conditions when using the Network Passive Sensor physical appliance.

• How can I test network connectivity?
• Need the model number or serial number for your appliance?
• Communication Failure message
• Appliance Configuration Errors

How can I test network connectivity?

Use a Laptop 

It is recommended that you test network connectivity to the Qualys Cloud Platform using your laptop (or other device).

Perform the following steps to test network connectivity:

1. Take the laptop to the location where the Network Passive Sensor be installed and connect the laptop to the network, using the same network cable and port that be used for the appliance.
2. Configure the laptop with the same network configuration that the Network Passive Sensor use (IP address, gateway, DNS server, and so on.).
3. If the connection to the Qualys Cloud Platform must pass through a proxy server, configure the laptop’s web browser with proxy information.
4. Open a browser and try to log into your Qualys account. You’ll see the Qualys Log In page after a successful connection is made to the Qualys Cloud Platform.

Test DNS Name Resolution

You can test DNS name resolution from any machine connected to the same network as your Network Passive Sensor. If DNS name resolution is working properly, server information is returned including the server name and IP address (Note that 'nslookup' is not available on all systems).

Need the Model Number or Serial Number for Your Appliance?

You can find this information on a sticker on your appliance. Depending on the model, it is either on the side of the appliance or the bottom.

Communication Failure Message

You get a COMMUNICATION FAILURE message if there is a network communications breakdown between the Network Passive Sensor and the Qualys Cloud Platform.

Why does it happen?

The communication failure may be due to one of these reasons: the network cable was unplugged from the appliance, the local network went down, or any of the network devices between the Network Passive Sensor and the Qualys Cloud Platform went down.

When does the message appear?

If any point of time communication breaks between Network Passive Sensor and Qualys Cloud Platform, then the COMMUNICATION FAILURE message appears.

How do I know the issue is resolved?

After the root cause is resolved, you get the COMMUNICATION FAILURE message until the next time the appliance makes a successful polling request to the Qualys Cloud Platform. Then you can see the appliance’s name and IP address and you can start using your appliance.

The COMMUNICATION FAILURE message may not disappear right away. There may be some lag after the network is restored and before the appliance is back online, depending on when the next polling request is scheduled. Additional time is necessary for communication to be processed by a Proxy server if the appliance has a Proxy configuration.

Appliance Configuration Errors

An appliance configuration error indicates the Network Passive Sensor attempted to connect to the Qualys Cloud Platform and failed.

The Network Passive Sensor is not functional until the error is resolved. Make sure to resolve the error.

You can see an error code and short description to help you with troubleshooting. Please refer to the short description provided to help you resolve the issue. If you still need help with the issue, please identify the error code when you contact Qualys Support.

Related Topic

Appendix A