ApplySarthiSenior Software Engineer — Embedded C / Firewall Client
SonicWall
Tailor my CV for this job, freeView job and applyYour CV rewritten for this role, from your real experience. Sign in with Google, nothing to install.
Got this interview? Our apps help you get the job.
Skills named in this job
Read from the description itself, not inferred.
This role on the market
14,325 open software roles across 1,179 companies are on ApplySarthi right now, most of them in Bengaluru (901), Hyderabad (292), Pune (179).
- Sr. Software Dev Engineer, AWS OpenSearch ServiceAmazon
- Principal Software Engineer– EDI & IntegrationsGsk · bengaluru
- Software Technologist IPhilips · bengaluru
- Senior Associate - Software EngineerPwc
- Senior Network Security/AI Software EngineeringIntel
What software roles keep asking for: Python (37%), Java (31%), AWS (29%), System design (26%), C++ (25%), CI/CD (23%), Observability (22%), Kubernetes (20%) — counted across their open postings here.
Software Engineer jobs in Bengaluru · Software Engineer jobs in India · Remote Software Engineer jobs · C++ jobs
SonicWall has 47 open roles listed here.
- Distinguished Engineer – Secure Private Access (SPA) / Zero Trustpune
- Senior Collections Analyst
- Senior Manager, Revenue Accounting
- Senior Software Engineer - DPDK experience is a must**pune
- Senior Manager, Test Engineering- Networking background is a mustbengaluru
Counted across 14 company job boards, updated as roles open and close.
Preparing for this interview
Interviews for software roles keep coming back to Python, Java, AWS, System design. Practise those questions before you sit with SonicWall.
Questions you are likely to be asked
- Why do you want to join SonicWall?
- What is your experience with C++? Tell me one thing you learned the hard way.
- Describe a time a deadline forced a trade-off in quality. What did you choose and why?
- How would you design an API for a feature you have worked on?
- What do you do when a production issue happens on your code?
Prep Sarthi gives you a free mock interview: an AI interviewer asks you questions like these out loud, from your own CV and this job, and shows your score and your weakest answer.
Practise the Senior Software Engineer — Embedded C / Firewall Client at SonicWall interview free →SonicWall is a cybersecurity forerunner with more than 30 years of expertise and is recognized as a leading partner-first company, ensuring our partners and their customers are never alone in the fight against cybercrime. With the ability to build, scale and manage security across the cloud, hybrid and traditional environments in real-time, SonicWall provides relentless security against the most evasive cyberattacks across endless exposure points for increasingly remote, mobile and cloud-enabled users. With its own threat research center, SonicWall can quickly and economically provide purpose-built security solutions to enable any organization—enterprise, government agencies and SMBs—around the world. For more information, visit www.sonicwall.com or follow us on Twitter, LinkedIn, Facebook and Instagram.
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-safe, and correctly handle all supported version transitions.
- Improve reliability of inter-blade cache synchronization on multi-blade appliances.
- Collaborate with the server-side on coordinated protocol changes.
- Document the concurrency model, upgrade invariants, and dataplane integration for long-term maintainability.
- Collaborate asynchronously with a US-based team and the India-based server team.
Requirements
- Expert-level C (not C++): disciplined manual memory management, pointer arithmetic, and systems design.
- Multi-core concurrency in C: reader-writer locks, spinlocks, atomic operations, and memory ordering.
- Kernel-level networking: deep understanding of how a packet moves through a firewall dataplane — TCP/UDP processing, flow cache, connection tracking. Userspace socket programming alone is not sufficient.
- Strong IPv4 and IPv6 across all code paths.
- Comfortable navigating and owning a large C codebase with multiple subsystems.
- Experience with network testing and debugging tools: packet capture (Wireshark/tcpdump), traffic generators, GDB.
- Good written English for remote, asynchronous collaboration.
Nice to have:
- Experience with multi-blade or multi-ASIC hardware platforms (Octeon/CVMX or similar).
- Understanding of symmetric encryption (AES-CBC, DES) at the C implementation level.
- Prior experience on a security appliance, network device, or UTM firmware codebase.
- Familiarity with TLV binary protocol design and versioning.
- Experience with C fuzz testing or sanitizers (AFL, AddressSanitizer, ThreadSanitizer).
Education & Experience
At least 8 years of related experience with a Bachelor's degree; or 6 years with a Master's degree; or a PhD with 3 years' experience; or equivalent experience preferred. Degree in Computer Science, Engineering, or related field preferred.
#LI-KB7
#LI-Hybrid
#C
#Firewall
#Networking
SonicWall is an equal opportunity employer.
We are committed to creating a diverse environment and are an equal opportunity employer. All qualified applicants receive consideration for employment without regard to race, color, ethnicity, religion, sex, gender, gender identity and expression, sexual orientation, national origin, disability, age, marital status, veteran status, pregnancy, or any other basis prohibited by applicable law.
At SonicWall, we pride ourselves on recruiting a diverse mix of talented people and providing active security solutions in 100+ countries.
Match this job to your CV
ApplySarthi scores your CV against this role, shows the skills you are missing, and writes a tailored version for the application.
Check my match →Similar open roles
- Distinguished Engineer - Data ArchitectSonicWall · pune
- Inside Territory Manager- Dutch SpeakerSonicWall
- Inside Territory Manager- Dutch SpeakerSonicWall
- Lead AI/ML Engineer – Security AI & LLMsSonicWall · pune
- Principal Frontend Engineer - React and TypeScript experience is required SonicWall · pune
- Product Marketing Senior ManagerSonicWall · bengaluru
- Senior Director, HardwareSonicWall
- Senior Principal Engineer – Wireless Access Points experience is preferred**SonicWall · pune
Need answers during your interview? Try Live Sarthi.
Live Sarthi, an Interview Sarthi app, shows answer suggestions during the call.
- Hidden from supported screen sharingThe overlay stays out of supported Windows screen captures.
- Answers start in about 1.5 secondsResponse time varies with your connection and model.
- From your own CVYour projects and your experience, not a generic script.
- 30 minutes freeThen ₹149 for a 2-day pass with unlimited calls — you pay for the days you are interviewing, not a subscription.
A Windows app, from the same team as ApplySarthi.
Listed on greenhouse · posted 2026-07-09. ApplySarthi collects openings and links to application pages; the role is advertised by SonicWall, not by us.