Senior Software Engineer - C/C++
First seen by Alion on Aug 10, 2026.
Job Description :
We are looking for a skilled Senior Software Engineer with strong expertise in C programming, Linux Kernel, networking protocols, VPN, and IPSec. The candidate will be responsible for designing, developing, enhancing, and troubleshooting high-performance networking and security products involving IPSec tunnels, packet processing, VPN technologies, and Linux-based systems.
Key Responsibilities :
- Design, develop, and maintain VPN and network security features using C/C++ on Linux platforms.
- Develop and enhance IPSec VPN tunnels, including tunnel establishment, packet encapsulation/decapsulation, and secure packet transmission.
- Work extensively with Linux Kernel networking and packet-processing components.
- Develop and troubleshoot networking modules, services, and components for high-throughput and low-latency environments.
- Analyze and debug IP packet flows, tunnel traffic, routing, and network connectivity issues.
- Implement and troubleshoot IPSec protocols, including IKE, ESP, and AH.
- Work with IKEv1/IKEv2 for secure VPN tunnel establishment and key negotiation.
- Analyze packet captures using tools such as Wireshark/tcpdump to identify protocol and connectivity issues.
- Develop kernel-level and user-space components for networking and security applications.
- Troubleshoot issues related to TCP/IP, UDP, IP routing, NAT, DNS, ARP, ICMP, and other networking protocols.
- Optimize packet-processing performance and memory/CPU utilization.
- Debug complex issues using GDB, core dumps, kernel logs, and Linux debugging tools.
- Collaborate with QA, product, and system teams to analyze defects and deliver production-quality networking features.
- Participate in design reviews, code reviews, unit testing, integration testing, and performance testing.
- Investigate customer-reported VPN/networking issues and provide root-cause analysis.
- Develop tools and utilities to monitor and measure network throughput, latency, packet loss, and tunnel performance.
Technical Skills :
- Strong programming experience in C/C++.
- Strong hands-on experience with Linux/Unix systems.
- Good understanding of Linux Kernel and Linux networking stack.
- Strong knowledge of VPN technologies, IPSec, IKE/IKEv1/IKEv2, ESP, AH.
- Strong knowledge of TCP/IP networking protocols (IPv4/IPv6, ICMP, ARP, DHCP, DNS, NAT, Routing, GRE).
- Strong debugging skills using GDB, tcpdump, Wireshark, strace, and Linux logs.
Preferred Skills :
- Strong understanding of StrongSwan or similar IPSec implementations.
- Experience with DPDK or other high-performance packet-processing frameworks.
- Knowledge of XFRM/IPSec implementation in Linux.
- Experience with firewall/security products, SASE/SD-WAN/SSE technologies.
- Knowledge of cryptographic libraries such as OpenSSL.
Education & Experience :
- Bachelor's/Master's degree in Computer Science, Information Technology, Electronics, Electrical Engineering, or a related field.
- Typically 5 to 10+ years of experience in networking/security software development.
- Relevant experience in VPN/IPSec/network security products preferred.
Skills
C, Linux Kernel, C++, VPN, IPsec, Troubleshooting, TCP/IP, TCP/UDP, Network Protocols