Zyxel Firewall [USG/USGFLEX/ATP/VPN] - Zyxel Firewall crash logging procedure

In case your USG/ZyWall/ATP/VPN/USGFLEX or any other professional firewall or router is crashing, please upgrade to the latest firmware version and collect console logs via the following procedure:

Disclaimer!  This article offers a general overview of the series and may not apply uniformly to every model, software/firmware version. Prior to purchasing or using the device, please consult the model/version-specific documentation or reach out to technical support for accurate information.

Upgrade the firmware

• Upgrade the firmware to the latest known firmware

Firewall [USG/ATP/VPN] - How to Update/Upgrade Firmware on USG/ATP/VPN

• Please also check our weekly firmware build. It's possible, that your issue was already fixed in it

Weekly Firmware / Support Version / Lab Version

• If you failed to install updates on your firewall, check out this article:

Zyxel security advisory for multiple buffer overflow vulnerabilities of firewalls - Unstable VPN Connection and web interface Login Issues

If the update did not help, please use the console cable to collect console logs for further investigation by tech support.

Connect to the console

CLI Commands [USG Series] - Overview of Helpful CLI Commands for USG Series

Connect to the console port of the USG using terminal software (in this case, we are using Putty)

Once you are in the CLI, use the following command to enhance the logging output:

Router> debug kernel console-level 8

Debug in CLI - Using Console to Access the Serial Port & Use Debug level 8 [Putty & TeraTerm]

Send the console logs to the Zyxel Support Team for analysis if the device still reboots and you clearly see messages about this in the logs.