Network Security Lead

Randstad; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Job summary

Randstad NV in London seeks a Senior Network Security Lead with 8+ years’ experience to own escalation for complex network and security incidents. You will drive high-availability operations, lead major RCAs, and enforce security posture in BPSS-governed environments.

You will manage lifecycle upgrades, patching, and configuration hardening across edge, campus, and core, including PAN-OS, Fortinet, Cisco FTD, and Meraki. A hands-on leader with cloud networking experience is essential.

Qualifications

• 8+ years of enterprise network and security operations experience.
• Hands-on with next-generation firewalls (Palo Alto, Fortinet or Cisco FTD) and enterprise VPNs.
• Experience with 802.1X/NAC deployments (Cisco ISE or equivalent).
• Active BPSS clearance or eligibility for BPSS screening.
• Cloud networking experience across AWS/Azure/GCP and SDN.
• Certs preferred: CCNP/CCIE, PCNSE.

Responsibilities

• Act as senior L3 escalation authority for network and security incidents.
• Lead incident, change, and problem management with SLA governance.
• Oversee hardware/software lifecycle upgrades and hardening across edge, campus, core.
• Provide 24/7 escalation coverage and participate in on-call rotations.
• Configure and harden perimeters and internal firewalls (PAN-OS, Fortinet, Cisco FTD, Meraki).
• Design and support NAC solutions (802.1X, MFA integrations).
• Mentor engineers and maintain SOPs, topology docs, and knowledge bases.

Skills

Network engineering

Incident management

Security engineering

L3 escalation

Scripting (Python, PowerShell, Ansible

Tools

Palo Alto

Fortinet FortiGate

Cisco FTD

Cisco ISE

NAC

Job description

• Location: London, UK (Hybrid – 2 days on-site/week)

We are seeking a senior, hands-on Network Security Lead with 8+ years of expertise spanning enterprise routing/switching, multi-vendor firewalls, Software-Defined Networking (SDN), and hybrid cloud connectivity.

In this role, you will act as the principal L3 technical escalation authority and operational lead across our secure network estate. You will drive high-availability network operations, lead major incident resolution, enforce rigorous security posture, and champion compliance within BPSS-governed and enterprise-scale environments.

• Serve as the senior Subject Matter Expert (SME) and primary escalation point for L3 network and security incidents, troubleshooting complex multi-technology outages through to root cause analysis (RCA).
• Oversee enterprise incident, change, and problem management processes, ensuring strict alignment with SLAs, operational resilience, and Change Advisory Board (CAB) governance.
• Lead scheduled hardware/software lifecycle upgrades, firmware patching, and configuration hardening across all edge, campus, and core infrastructure.
• Provide escalation coverage within a 24/7 operational framework, participating in on-call rotations and critical response scenarios.
• Administer, tune, and harden enterprise perimeter and internal firewalls across Palo Alto (PAN-OS), Fortinet (FortiGate), Cisco FTD, and Cisco Meraki.
• Design, deploy, and support enterprise Network Access Control (NAC) via Cisco ISE, covering 802.1X policy enforcement, posture assessment, guest access, and multi-factor authentication (MFA) integrations.
• Monitor vulnerability advisories, evaluate threat profiles, execute remediation programs, and maintain adherence to audit baselines and BPSS (Baseline Personnel Security Standard) standards.

Core Routing, Switching & Infrastructure Operations

• Configure, optimize, and troubleshoot large-scale data center and enterprise campus fabrics, including Cisco Nexus, Aruba, Dell, and HP hardware estates.
• Maintain advanced routing and data center protocols, including BGP, OSPF, EIGRP, VXLAN/EVPN, DMVPN, HSRP/GLBP, and VPC.
• Manage enterprise wireless infrastructures across Cisco, Aruba, and Meraki controllers and access points, ensuring optimized RF coverage and guest/corporate network isolation.
• Identify and build operational automation scripts using Python, PowerShell, or Ansible to streamline routine configurations, backups, and health checks.
• Maintain clear operational documentation, Standard Operating Procedures (SOPs), network topologies, and knowledge-transfer repositories.
• Mentor, train, and guide mid-level network and security engineers, promoting best practices in technical governance and customer stakeholder communication.

Qualifications & Experience

Essential

• Experience: Minimum 8 years of dedicated experience delivering and supporting enterprise-grade network and security operations.
• Routing & Switching: Proven mastery of Cisco data center and campus platforms (Catalyst, Nexus) and industry routing protocols (BGP, OSPF, VXLAN).
• Network Security: Deep hands-on engineering background with next-generation firewalls (Palo Alto, Fortinet, or Cisco FTD) and enterprise VPN architectures (IPsec, SSL).
• Identity & NAC: Practical deployment and troubleshooting experience with Cisco ISE or comparable 802.1X authentication systems.
• Security Clearance: Must hold active BPSS clearance or be fully eligible to undergo BPSS pre-employment screening.
• Prior experience in high-level or low-level Network Architecture & Design.
• Enterprise Cloud Networking experience across AWS, Azure, or GCP (e.g., Transit Gateways, DirectConnect/ExpressRoute, Virtual Appliances).
• Scripting capability for network automation (Python, REST APIs, Ansible).
• Professional certifications: CCNP / CCIE (Enterprise or Security), PCNSE, or equivalent vendor accreditation.