IT Security Senior Engineer

Donnelley Financial Solutions (DFIN); United States; On-site; USD 140,000 - 190,000; Full time

Benefits offered by this job

Competitive compensation

Flexible workplace

Comprehensive benefits

Growth opportunities

Job summary

DFIN is seeking a Senior Network Security Engineer to provide advanced engineering leadership for enterprise network security across cloud and on-prem environments. You will design secure architectures for LAN/WAN, own medium-to-large initiatives such as segmentation and firewall modernization, and drive modernization aligned to Zero Trust.

Mentor engineers, set standards, coordinate incidents, develop runbooks, and partner with vendors to deliver secure, scalable network platforms with

Qualifications

• Bachelor’s degree in Computer Science, IT, or related field (preferred) or equivalent experience.
• 7-10+ years of hands-on experience in network security engineering, including cloud networking and enterprise platforms.

Responsibilities

• Lead the design of secure LAN/WAN architectures and hybrid cloud/SaaS environments.
• Own medium-to-large initiatives (segmentation, SASE expansions, firewall modernization) from design through delivery.
• Lead incident response as Level 3 escalation and drive post-incident analysis and systemic fixes.

Skills

Network security

Cloud networking

Zero Trust

SASE

CI/CD

Education

Bachelor’s degree or equivalent

Tools

Azure

SIEM

NDR

PowerShell

Job description

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Join a dynamic team at the pulse of global markets, where we deliver innovative software and service solutions for essential financial reporting and capital markets transactions. At DFIN, we are a values-driven organization that empowers you to build a fulfilling career while bringing your authentic self to work every day.Our "Win as One" mentality ensures that our team's success is directly linked to Client, Shareholder and Employee Satisfaction.

In 2026, DFIN was named #1 on the 2026 Top 100 Global Most Loved Workplaces® by Best Practice Institute. We have also been recognized as one of America's Most Loved Workplaces® for five consecutive years and a Built In Best Place to Work for six years, reflecting our continued commitment to supporting employees' total well-being. Bring your passion and talents to DFIN - because being YOU thrives here.

• competitive compensation
• a flexible workplace
• comprehensive benefits
• opportunities for professional growth

Summary:

The Senior Network Security Engineer provides advanced engineering expertise and technical leadership for enterprise network security across cloud and on-prem environments. This role leads complex designs and implementations, serves as a senior escalation point for major incidents, and drives modernization initiatives aligned to DFIN's Zero Trust strategy. The senior engineer mentors other engineers, shapes standards, and partners with stakeholders to deliver secure, scalable, and resilient network security platforms.

Responsibilities:

• Lead the design of secure architectures for LAN/WAN, hybrid cloud, and SaaS environments; define reference patterns.
• Own medium-to-large initiatives (e.g., segmentation, SASE expansions, firewall modernization) from design through delivery.
• Contribute to multi-year roadmaps by identifying gaps, reducing technical debt, and aligning to Zero Trust outcomes.

Advanced Network Security Engineering

• Engineer and optimize advanced firewall/WAF capabilities, DDoS protections, API security patterns, and load balancing controls.
• Design Azure connectivity and security controls at scale (hub/spoke, shared services, private connectivity, routing strategy).
• Implement and operationalize microsegmentation strategies and integrate with identity and endpoint signals.
• Lead integrations with telemetry and NDR tools to improve detection fidelity and end-to-end visibility.

Operational Excellence & Incident Leadership

• Act as Level 3 escalation for high-severity incidents; coordinate technical response and ensure timely mitigation.
• Lead root-cause analysis, author post-incident reports, and drive systemic fixes and resilience improvements.
• Establish and improve runbooks, operational metrics, and reliability practices for owned platforms; guide on-call readiness.

Additional Responsibilities

DevSecOps & Automation (Technical Lead)

• Define automation standards for network/security workflows; build reusable modules and guardrails for safe changes.
• Partner with platform engineering to embed secure connectivity controls into CI/CD and infrastructure-as-code pipelines.

Mentorship & Cross-Functional Leadership

• Mentor engineers in architecture, troubleshooting, and secure design; provide technical reviews and guidance.
• Influence stakeholders by presenting options, risks, and recommendations; partner with vendors to resolve complex issues.
• Enterprise firewalls (on-prem and cloud), WAF, DDoS protection, API security, and load balancing
• Microsegmentation/segmentation design and enforcement; Zero Trust access patterns (ZTNA)
• SASE/SSE and SD-WAN architectures; identity-integrated access and policy strategies
• Azure network architecture at scale (hub/spoke, routing, private endpoints, shared services, resiliency patterns)
• Telemetry, logging, SIEM integrations, and NDR tool integrations to improve detection and response
• Advanced automation/scripting (Python/PowerShell), CI/CD, and infrastructure-as-code practices

Qualifications:

Education & Experience

• Bachelor’s degree in Computer Science, IT, or related field (preferred) or equivalent experience.
• 7-10+ years of hands-on experience in network security engineering, including cloud networking and enterprise platforms.

Certifications (Preferred/Highly Desired)

• CCNP/CCIE (Security or Enterprise) or equivalent experience.
• Cloud networking/security certifications (Azure preferred; AWS/GCP a plus).
• SASE/SD-WAN certifications (e.g., Zscaler) are a plus.

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