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About the Role
SonicWall is hiring a Senior Software Engineer to develop and maintain the Content Filtering Service client embedded in SonicOS — the firmware running on SonicWall firewall appliances worldwide. This module intercepts live traffic,
queries the CFS rating servers in real time, and enforces URL-based content filtering policies at the packet level. This is security-critical code: a policy bug is a traffic bypass on a deployed security appliance.
The codebase is in C with a split Control Plane / Data Plane architecture, multi-blade cache synchronization, and multiple firmware version upgrade paths.
Responsibilities
Maintain, harden, and extend the CFS client module across both the control plane and data plane.
Own the binary UDP protocol implementation between the firewall and the CFS rating servers, ensuring correctness and compatibility across protocol versions.
Develop and maintain complete IPv4 and IPv6 support across all code paths.
Own the firmware upgrade and migration paths, ensuring they are atomic, failure-secure, and correctly handle all supported version transitions.
Improve reliability of inter-blade cache synchronization on multi-blade applian