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Gareth Doyle

Senior Network Security Engineer

Professional Summary

Senior Network Security Engineer with 10+ years securing large-scale hybrid cloud and on-premises infrastructure, including 6+ years administering an enterprise environment of 3,500+ firewalls at a Fortune 50 retailer. Led enterprise-wide Zero Trust Network Access (ZTNA/SASE) deployments, and currently driving microsegmentation with Akamai Guardicore, cloud firewall automation in GCP, and identity-based access integration with Entra ID. MS in Cybersecurity and Information Assurance; U.S. Air Force veteran with a proven record of leading teams, authoring documentation, and operating independently in remote, cross-functional settings.

Core Technical Skills

Firewalls & Network Security

Palo Alto NGFW / Panorama, Fortinet FortiGate, Cisco ASA, Check Point, microsegmentation (Akamai Guardicore), firewall policy design, network segmentation, SSL inspection, DLP

Zero Trust / SASE / VPN

FortiSASE, Atmos by Axis (HPE), Zscaler ZPA/ZIA, GlobalProtect, FortiClient, Cisco AnyConnect, clientless ZTNA

Cloud & Automation

GCP, Azure, OCI; cloud-native firewall deployment, Panorama automation, Python (scripting familiarity), Linux

Identity & Access

Microsoft Entra ID, identity-based access control, least-privilege enforcement, IAM collaboration

Security Operations

SIEM analysis (Splunk, OpenSearch), EDR telemetry, incident response support, threat hunting / IOC analysis, vulnerability mitigation

Infrastructure Services

Infoblox DNS/DHCP, DNS sinkholing, F5 LTM/WAF (iRules, VIP management), Cisco routing/switching (NX-OS, Catalyst)

Governance & Frameworks

NIST SP 800-53, NIST SP 800-207 (Zero Trust), ISO 27001, FedRAMP environments, security documentation & runbooks

Professional Experience

Senior Network Security Engineer
Lowe's Companies, Inc. (Fortune 50) — Charlotte, NC (Remote)
06/2020 – Present
  • Administer and maintain enterprise firewall infrastructure of 3,500+ Palo Alto and Fortinet firewalls across centralized and decentralized deployments, including full lifecycle upgrades, patching, and hardware refresh cycles.
  • Led the enterprise rollout of Zero Trust Network Access, deploying Atmos by Axis and later migrating the environment to FortiSASE, integrated with IAM, EDR, and SSE platforms to reduce attack surface.
  • Implementing an enterprise microsegmentation initiative using Akamai Guardicore, designing segmentation policies that restrict lateral movement and reduce attack surface across enterprise workloads.
  • Architected and implemented Atmos Air, a clientless ZTNA web solution built from the ground up to give third-party partners secure access to enterprise systems without endpoint agents.
  • Scaled Palo Alto NGFWs in GCP using cloud-native deployment methods and Panorama integration, enabling automated, consistent policy enforcement across cloud workloads.
  • Evaluate and implement risk-based, non-standard firewall change requests for complex enterprise applications while maintaining compliance with segmentation strategy and NIST SP 800-53-aligned policy governance.
  • Integrate identity-based access controls with Microsoft Entra ID, enforcing least-privilege access in partnership with IAM and security architecture teams.
  • Analyze SIEM (Splunk, OpenSearch) and EDR telemetry to support incident response, APT investigations, IOC identification, and enterprise hardening initiatives.
  • Administer Infoblox DNS/DHCP services, including DNS sinkholing and blocklist enforcement supporting threat containment.
  • Tune F5 WAF rule sets with application teams to reduce false positives; author operational runbooks and lead internal training for security and operations teams.
Senior Network Administrator
BlueCross BlueShield of South Carolina — Columbia, SC
09/2018 – 05/2020
  • Redesigned a FedRAMP-secure network environment, improving segmentation, routing, and overall firewall posture for regulated workloads.
  • Reduced firewall rule complexity by approximately 25%, improving operational efficiency and audit readiness.
  • Administered Infoblox DNS/DHCP and supported F5 WAF rule tuning; escalated and resolved network and vendor issues under strict SLA and change-management processes.
Network Administrator
BlueCross BlueShield of South Carolina — Columbia, SC
11/2016 – 09/2018
  • Maintained LAN/WAN security and availability across enterprise systems, diagnosing and resolving critical performance and security incidents in real time.
  • Performed day-to-day network administration, monitoring, and alert response, including DNS/DHCP operations and DNS sinkhole enforcement.
Network Technician (Contract)
BlueCross BlueShield of South Carolina via TM Floyd & Co. — Columbia, SC
02/2016 – 11/2016
  • Troubleshot and resolved hardware, software, and network issues; supported end users locally and remotely.
Systems and Network Administrator
Receivable Solutions, LLC — Columbia, SC
07/2014 – 02/2016
  • Configured and supported workstations and network infrastructure; assisted with firewall configurations, B2B network integrations, and backup operations.
Aircrew Egress Systems Craftsman (Non-Commissioned Officer)
United States Air Force — Phoenix, AZ
12/2003 – 04/2014
  • Led teams of 4–16 personnel in high-risk operational environments, assigning workloads and priorities under strict safety and quality compliance.
  • Developed process improvements that reduced job completion time while increasing inspection pass rates by 20%.

Certifications

AWS Certified Cloud Practitioner — 2026
CompTIA PenTest+ — 2024
CompTIA CySA+ — 2023
ISC2 Certified in Cybersecurity (CC) — 2023
Cisco CCNP Enterprise — 2019 (expired 2025)
Cisco Certified Specialist — Enterprise Core & Advanced Infrastructure Implementation, 2019

Education

MBA, IT Management (in progress) Western Governors University 2027
MS, Cybersecurity and Information Assurance Western Governors University 2025
BA, Business Information Systems Ashford University — Summa Cum Laude 2014