Senior Network Security Engineer at Bounteous, London Area, £Contract Rate

Job Title: Senior Firewall & Network Security Engineer

Location: London

Position Type: Contract

Overview

We are seeking an experienced Senior Firewall & Network Security Engineer with deep expertise in the Fortinet ecosystem to join our infrastructure security team. In this role, you will design, manage, and continuously improve enterprise-grade firewall infrastructure, lead firmware upgrade cycles, drive automation initiatives, and serve as the subject-matter expert on FortiGate platforms — including the 1500D and 1800F series. You will work cross-functionally with network, cloud, and compliance teams, operating within ITIL-aligned change management processes.

Key responsibilities:

Own end-to-end management of enterprise FortiGate firewalls (1000-series and above) across production and non-production environments, including VDOM configuration, HA setup, and policy routing.

Plan and execute FortiOS major-version upgrade paths (e.g., 6.x → 7.x) in production, including firmware validation, compatibility matrix review, pre/post checklists, and rollback procedures.

Lead hardware migration and refresh projects for Fortinet infrastructure — from staging through production cutover — with full documentation and stakeholder communication.

Administer and tune the FortiGate 1800F platform, leveraging the NP7 network processor architecture for high-performance traffic inspection and security policy enforcement.

Manage the Fortinet centralised management stack: FortiManager (policy and configuration management), FortiAnalyzer (logging and reporting), and FortiClient EMS (endpoint visibility).

Develop and maintain network automation workflows using Ansible, Python, or the Fortinet REST API to reduce manual toil and enforce configuration consistency.

Author change requests, risk assessments, and runbooks aligned to ITIL practices, managing approvals and execution through ServiceNow or Jira.

Perform advanced CLI-level troubleshooting and debug command analysis to resolve complex network and security incidents within SLA.

Collaborate with security operations and architecture teams to continuously harden firewall policies, reduce attack surface, and meet compliance requirements.

Required experience

5–7 years in firewall engineering, network security operations, or infrastructure security roles.

Demonstrated experience managing FortiGate firewalls in enterprise environments (1000-series or higher strongly preferred).

Proven track record executing at least one large-scale Fortinet hardware migration or refresh project.

Hands-on FortiOS major-version upgrades in production environments.

Working knowledge of ITIL practices, change management, and ticketing platforms (ServiceNow, Jira).

Preferred qualifications

Fortinet NSE 4, NSE 7, or NSE 8 certification.

Experience with the FortiGate 1800F hardware platform and NP7 processor architecture.

Proficiency in Python or Ansible for network automation at scale.

Exposure to SD-WAN, zero-trust segmentation, or cloud security gateway architectures.

Familiarity with multi-VDOM designs in large enterprise or service provider environments.

Regards

Anita