Technical Tip: How to Troubleshoot FortiDDoS-B boot loop issue

Description

This article describes how to troubleshoot a FortiDDoS-B boot loop and provides a step-by-step guide to resolve it.

Scope

FortiDDoS-B.

Solution

1. Connect via serial console:

• Verify whether the system is completing the boot process or continuously restarting.

• Capture the complete console output, including any error messages or error codes displayed during the boot loop.

If possible, take clear screenshots or record the serial console session, as this information will be required for further troubleshooting and TAC analysis.

2. Review console output.

• Monitor the console output during boot.

• Look for kernel panics, filesystem errors, hardware failures, RAM activation or any other messages that may indicate the root cause of the boot loop.

3. Verify software version.

• Check the currently installed FortiDDoS software version.

• If the appliance is running an older release, consider upgrading to a supported version to benefit from the latest bug fixes, security patches, and stability improvements.

4. Perform a power cycle (workaround to recover system access).

• As a temporary workaround to recover system access, power off the FortiDDoS appliance completely.

• Wait approximately 30 seconds, then power the appliance back on.

• Verify whether the system completes the boot process successfully or continues to experience the boot loop.

• If the appliance becomes accessible after the power cycle, collect the necessary logs and diagnostic information before performing any additional changes or rebooting the system again.

5. Collect diagnostic information (if the appliance becomes accessible):

• Enable reboot on graceful recovery under global settings to allow the device to recover from certain failures automatically.

• Review the event logs for crashes, configuration issues, or other abnormal events.

• Configure a remote syslog server to collect logs for further analysis if possible.

Additional information about troubleshooting tools can be found in the FortiDDoS Handbook: tools.

6. Open a Fortinet TAC Case (if the issue persists).

• If the appliance continues to experience a boot loop after completing the steps above, open a Fortinet TAC support case. See Fortinet Support.

Include the following information:

• Current FortiDDoS version.

• Console boot logs (serial console output).

• Event logs (if available).

• Description of the issue and when it started.

• Any recent configuration changes or upgrades performed.

• Backup file.

Note: Additional troubleshooting or hardware diagnostics may be required depending on the console output and the behavior observed during the boot process.