- Products
- Network Security
Next Generation FirewallNext-generation firewall for SMB, Enterprise, and Government
Security ServicesComprehensive security for your network security solution
Network Security ManagerModern Security Management for today’s security landscape
- Advanced Threat Protection
Capture ATPMulti-engine advanced threat detection
Capture Security applianceAdvanced Threat Protection for modern threat landscape
- Access Security
Cloud Edge Secure AccessDeploy Zero-Trust Security in minutes
Secure Mobile AccessRemote, best-in-class, secure access
Wireless Access PointsEasy to manage, fast and secure Wi-FI
SwitchesHigh-speed network switching for business connectivity
- Email Security
Email SecurityProtect against today’s advanced email threats
- Cloud Security
Cloud App SecurityVisibility and security for Cloud Apps
Cloud Firewall (NSv)Next-generation firewall capabilities in the cloud
- Endpoint Security
Capture ClientStop advanced threats and rollback the damage caused by malware
Content Filtering ClientControl access to unwanted and unsecure web content
- Product Widgets
- Product Menu Right Image
-
- Network Security
- Solutions
- Solutions Widgets
- Solutions Image Widgets
-
- Solutions Widgets
- Partners
- Partner Widgets
- Partners Image Widgets
-
- Partner Widgets
- Support
- Support Widget
- Support Image Widgets
-
- Support Widget
- Products
- Network Security
- Next Generation FirewallNext-generation firewall for SMB, Enterprise, and Government
- Security ServicesComprehensive security for your network security solution
- Network Security ManagerModern Security Management for today’s security landscape
- Advanced Threat Protection
- Capture ATPMulti-engine advanced threat detection
- Capture Security applianceAdvanced Threat Protection for modern threat landscape
- Access Security
- Cloud Edge Secure AccessDeploy Zero-Trust Security in minutes
- Secure Mobile AccessRemote, best-in-class, secure access
- Wireless Access PointsEasy to manage, fast and secure Wi-FI
- SwitchesHigh-speed network switching for business connectivity
- Email Security
- Email SecurityProtect against today’s advanced email threats
- Cloud Security
- Cloud App SecurityVisibility and security for Cloud Apps
- Cloud Firewall (NSv)Next-generation firewall capabilities in the cloud
- Endpoint Security
- Capture ClientStop advanced threats and rollback the damage caused by malware
- Content Filtering ClientControl access to unwanted and unsecure web content
- Product Widgets
- Product Menu Right Image
-
- Network Security
- Solutions
- Solutions Widgets
- Solutions Image Widgets
-
- Solutions Widgets
- Partners
- Partner Widgets
- Partners Image Widgets
-
- Partner Widgets
- Support
- Support Widget
- Support Image Widgets
-
- Support Widget
VPN Decryption Failed Alert
10/14/2021 
122 People found this article helpful
111,967 Views
Description
The firewall displays the log "VPN Decryption Failed" in the Log Monitor or in the packet monitor.
Cause
This error could be related to an encrypted packet which has been fragmented and so the appliance is not able to decrypt it.
Resolution
Resolution for SonicOS 6.5
This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.
NOTE: This error is most likely due to 3rd party connections (i.e. ISP connections) that are fragmenting IPSec packets.
On the SonicWall you will need to make sure the options "Enable Fragmented Packet Handling" is ticked and "Ignore DF Bit" is disabled to ensure the correct handling of those packets by the SonicWall. However, this is only a workaround that might help in garbled environments and does not always fix the issue. If the issue persists, the root cause should be investigated on the ISP or remote side of the VPN as the packets are arriving corrupted on the SonicWall.
You can find the options above under Manage | VPN | Advanced Settings:
Resolution for SonicOS 6.2 and Below
The below resolution is for customers using SonicOS 6.2 and earlier firmware. For firewalls that are generation 6 and newer we suggest to upgrade to the latest general release of SonicOS 6.5 firmware.
NOTE: This error is most likely due to 3rd party connections (i.e. ISP connections) that are fragmenting IPSec packets.
On the SonicWall you will need to make sure the options "Enable Fragmented Packet Handling" is ticked and "Ignore DF Bit" is disabled to ensure the correct handling of those packets by the SonicWall. However, this is only a workaround that might help in garbled environments and does not always fix the issue. If the issue persists, the root cause should be investigated on the ISP or remote side of the VPN as the packets are arriving corrupted on the SonicWall.
You can find the options above under VPN | Advanced:
Related Articles
Categories
- Firewalls > TZ Series
- Firewalls > SonicWall SuperMassive E10000 Series
- Firewalls > SonicWall SuperMassive 9000 Series
- Firewalls > SonicWall NSA Series
YES
NO