Deep Packet Inspection of Secure Socket Layer (DPI-SSL) extends SonicWall's Deep Packet Inspection technology to the inspection of encrypted HTTPS traffic and other SSL-based traffic. The SSL traffic is decrypted (intercepted) transparently, scanned for threats, and then re-encrypted and, if no threats or vulnerabilities are found, sent along to its destination.
After performing DPI-SSL inspection, the appliance re-writes the certificate sent by the remote server and signs this newly generated certificate with the certificate specified in the Client DPI-SSL configuration. By default, this is the firewall certificate authority (CA) certificate, but a different certificate can be specified. Users should be instructed to add the certificate to their browser's trusted list to avoid certificate trust errors.
TIP: It is always recommended to create your own DPI SSL Certificate For The Purpose Of DPI-SSL Certificate Resigning. You can refer to How Can I Create A DPI-SSL Certificate For The Purpose Of DPI-SSL Certificate Resigning? for the same.
For more details on DPI SSL, please check Where Can I Learn More About DPI-SSL?