Senior Network Security Engineer

NorthMark Strategies•Dallas, TX

About The Position

The Network Security Engineer is a hands-on technical role within NMC²’s centralized Security Engineering organization, responsible for designing and maintaining the network security infrastructure that protects our hyperscale HPC and cloud compute environment. This role plays a direct part in building the controls, automation, and operational practices that keep NMC²’s infrastructure secure at scale. You would contribute to the design, development, and delivery of critical network security components within complex, enterprise-scale systems and projects. This role brings strong technical depth in network security architecture and controls, applying sound judgment to resolve complex problems and balance technical integrity with delivery speed. Working closely with the Manager of Network and Infrastructure Security and cross-functional peers, the Senior Security Engineer drives meaningful improvements to the organization's security posture while serving as a subject matter expert and mentor within the team.

Requirements

7+ years of experience in network security engineering, with hands-on experience across trusted, untrusted, and DMZ environments
Strong understanding of network protocols and the OSI model, with practical experience in TCP/UDP-based applications, routing, switching, and load balancing
Experience securing both on-premises and cloud network environments (AWS, Azure, or GCP)
Experience designing and securing network environments across both on-premises and cloud platforms (AWS, Azure, or GCP)
Proven ability to identify and deliver process improvements, automation opportunities, and tool enhancements within a security engineering function
Experience with security monitoring tools and SIEM platforms, with the ability to investigate and respond to network-based threats
Strong understanding of security frameworks and hardening standards such as NIST, CIS Benchmarks, or ISO 27001
Effective communicator with the ability to articulate technical decisions and trade-offs clearly to both technical peers and leadership
Must be legally authorized to work in the United States without the need for employer sponsorship, now or at any time in the future.

Nice To Haves

Relevant certifications preferred, such as CCNP Security, PCNSE, CISSP, or equivalent
Experience with VxLAN EVPN data center architecture
Background in SOC operations or working with MSSPs
Firewall automation experience

Responsibilities

Contribute to the design, implementation, and delivery of scalable network security architecture and controls including firewalls, IDS/IPS, and VPNs across on-premises and cloud environments
Serve as the team's primary subject matter expert for network security technologies, providing guidance and technical direction on complex security challenges
Apply technical depth and sound judgment to resolve complex network security challenges, making trade-offs that balance security requirements with operational and delivery needs
Collaborate effectively with cross-functional peers across infrastructure, cloud, and IT operations, communicating technical decisions and progress with clarity and ensuring alignment across teams
Develop and maintain network security standards, policies, and technical documentation
Support network segmentation and micro-segmentation efforts by providing technical expertise on traffic flows, access controls, and policy enforcement
Participate in security architecture reviews for new projects, systems, and third-party integrations to ensure network security requirements are addressed
Mentor junior security engineers and contribute to the overall growth and development of the network security team