How to Understand and Resolve Settings Corruption

03/26/2020 1291 20022

DESCRIPTION:

While SonicOS Settings and Firmware can often be upgraded and Imported to and from various versions, not all Imports and Upgrades are supported. In some instances this is because one version of SonicOS is too old to go into another, or there were incompatibilities between two versions. Other functions, such as a straight downgrade of the SonicWall Firmware, are always unsupported regardless of SonicOS version.

This article will detail which configurations on the SonicWall are unsupported, what unsupported Settings or Firmware means for a SonicWall, and how to resolve it.

CAUSE:

Unsupported Settings and Firmware Configuration

If an attempt to downgrade SonicWall firmware is performed, the lower firmware will be unable to recognize settings created on the higher version of firmware.  As the SonicWall is not designed to perform such a downgrade, it will attempt to cram them into the lower firmware anyway.  This will inevitably force settings for one engine, such as User Authentication, into a completely unrelated section of the configuration, such as the VPN engine, where none of these items make any sense.

Because of this, it is impossible for SonicWall to predict the behavior of the firewall, and therefore to support the device, after the configuration has gone through a direct downgrade of firmware.

TIP: The following procedures ARE supported by SonicWall, as they do not constitute a downgrade of settings:

• Booting the SonicWall from a higher version of Firmware to a lower Firmware version with the Factory Default Settings and rebuilding the settings manually.
• Booting the SonicWall to a lower Firmware with Factory Default Settings and then Importing a supported Settings File taken from an equal or lower version of Firmware.

CAUTION: SonicWall does NOT support any the following procedures:

• A direct downgrade of Firmware on any SonicWall product (I.E. - Booting to 5.8.1.12 firmware with current settings on a SonicWall already running 5.8.1.13 firmware).
• Attempting to resolve a Firmware downgrade issue by importing a known good configuration file to a SonicWall that has gone through an unsupported downgrade without first booting to Factory Default Settings.
• Attempting to support, repair, or use in any way a .exp Settings Configuration file exported from a SonicWall with corrupt settings after a Firmware downgrade was performed on it.
• Importing a Settings File that was taken from a SonicWall running a higher Firmware version and import it into a SonicWall running lower Firmware version, this will then corrupt the configuration.
• Importing Settings or Upgrading Firmware that is not in accordance with the Supported Matrix.
• A SonicWall that is on a Beta Firmware or has ever been on a Beta Firmware. As detailed in the SonicWall Beta Program, all Beta Testers are expected to Factory Default and rebuild the Settings once Beta Testing is concluded.
• A SonicWall that has any Settings File taken from the SonicWall Migration Tool. This tool is in Beta and is not recommended for live environments.

CAUTION: Attempting to upgrade the Firmware after performing an unsupported Firmware Downgrade, Upgrade, or Settings Import does not resolve Settings Corruption!

While issues may not be noticed immediately, they will start to appear as further configuration changes and Firmware updates are applied. Due to this unpredictable behavior, SonicWall cannot provide support for any device using an unsupported Settings File.

RESOLUTION:

Settings corruption only has two supported resolutions, as detailed below:

• Factory Defaulting the SonicWall and rebuilding all Settings. This is the same as doing an out of the box build, the SonicWall must have no remnants of the previous Settings File or the unsupported Settings will longer.
• Factory Defaulting the SonicWall and Importing a supported, uncorrupted Settings File. From here it may be necessary to rebuild some Settings depending on when the supported Settings File was taken.

At this time there is no way to manually clean a Settings File, nor is there a way to mitigate the damage that an unsupported Settings File can do.

As of 6.5.0.0-40n there is another way to resolve settings corruption.  As the .exp configuration file is the source of the corruption, a workaround is in place where the CLI commands can be exported from the firewall (5.9 & Above) and imported into a factory deftaulted firewall running 6.5.0.0-40n or later.  For information on how to complete this the following actions are required:

1. Follow this KB to export the configuration to a list of cli commands into a txt file: Export configuration settings using Enterprise Command Line Interface (E-CLI) 

2. On the Manage tab, access the Firmware & Backups page and click to boot to the current firmware with factory default settings. (Older than 6.5?  This is located on the System | settings page.  To complete you will need to upload 6.5.0.0-40n or later and boot to uploaded configuration with factory default settings)

3. Access the sonicwall via X0 at 192.168.168.168 (tz appliances) or via MGMT port at 192.168.1.254 (NSA or Supermassives)

4. Enable SSH on the port being accessed.  (If NSA/Supermassive device, you will need to configure a port other than MGMT to be able to use the FTP feature.  This will be the interface you log in to and SSH to).

5. Follow the KB here to complete the import process: How to import a cli text file into a firewall