Network Engineer

Falconsmartit; Guildford; On-site; GBP 85,000 - 120,000; Full time

Job summary

Falconsmartit is seeking a Senior Network Security Engineer (L4) to design, implement, and optimize enterprise security across multi-site data centers in the UK. You will work with Cisco security technologies, Check Point firewalls and F5 APM to deliver secure, scalable network solutions.

The role involves hands-on installations, upgrades, migrations and decommissioning, plus cross-team collaboration. You will produce high level designs, SOPs, incident RCA reports, and mentor junior engineers

Qualifications

• 6–10+ years of strong experience in enterprise Network Security.
• Experience in large, distributed, high-availability environments.
• Proven track record leading install, upgrade, migration, and decommission projects.
• Experience handling major incidents and RCA documentation.

Responsibilities

• Design, implement, and optimize enterprise security across multi-site data centers.
• Install, configure and deploy Cisco/Check Point/F5 devices; manage refresh and migrations.
• Lead L4 investigations; troubleshoot VPN, ASA/FTD, and firewall issues; perform RCA.
• Ensure compliance with ISO 27001, NIST, PCI-DSS and maintain SOPs.
• Collaborate with cross-functional/global teams to review security requirements.

Skills

Communication

Troubleshooting

Documentation

Mentoring

Leadership

Tools

Cisco ASA/FTD

FMC

Check Point Firewall

F5 APM

Cisco ISE

Nexus switching

Wireshark

VPN

Automation Scripting

Job description

Job Location: Guildford OR Bournemouth, UK

Job Description: Senior Network Security Engineer (L4)

Role Overview

We are seeking a highly skilled L4 Network Security Engineer with deep expertise in Cisco security technologies, Check Point firewalls, and F5 APM. The ideal candidate will be responsible for designing, implementing, optimizing, and troubleshooting enterprise security solutions across multi-site and data center environments. This role requires hands-on experience in platform installations, upgrades, migrations, and decommissioning activities, along with strong troubleshooting and cross-team collaboration skills.

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Key Responsibilities

1. Security Infrastructure Operations & Engineering

Manage, configure, and troubleshoot Cisco ISE (TACACS+, RADIUS, Dot1X, CoA, Profiling).

Administer and support Cisco ASA/FTD firewalls including ACLs, NAT, VPN, failover, clustering, and upgrades.

Manage Check Point firewalls (R80.x) policy management, clustering, VPN, logging, and health checks.

Handle F5 APM for remote access VPN, SSO, authentication policies, and application access.

Support data center network security architecture (firewalls, segmentation, VRF, routing, switching security).

2. Implementation, Installations & Decommissioning

Perform installation, configuration, and deployment of security devices (ASA/FTD, Check Point, ISE nodes, F5 APM).

Lead hardware refresh, firewall replacement, and migration projects.

Execute device decommissioning, ensuring proper cleanup of configs, rule removal, rack removal, and documentation.

Conduct cutover activities, change execution, and post-implementation validation.

Participate in designing secure network architectures for enterprise and data center environments.

Work with cross-functional teams to review network and security requirements.

Create and maintain HLDs/LLDs, network diagrams, migration plans, and SOPs.

4. Security Operations & Troubleshooting

Act as L4 SME for escalations related to network security issues.

Troubleshoot identity/authentication failures, VPN issues, firewall packet drops, routing conflicts.

Perform root-cause analysis (RCA), remediation plans, and long-term fixes.

Monitor system health, logs, and alerts across multiple platforms.

5. Governance, Compliance & Best Practices

Ensure compliance with security standards (ISO 27001, NIST, PCI-DSS, CIS benchmarks).

Conduct periodic rule/policy optimization, cleanup, and audits.

Maintain device firmware/software to secure and supported versions.

Document operational procedures and provide knowledge transfer to L1/L2 teams.

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Required Skills & Experience

Technical Skills

Cisco ASA/FTD VPN, NAT, ACL, clustering, routing, packet tracer, Firepower Management Center (FMC).

F5 APM Access policy creation, VPN configuration, SAML/OAuth integration.

Cisco Switching/Routing in DC environment Nexus (5k/7k/9k), VLANs, VPC, OSPF/BGP basics.

Packet capture tools: Wireshark, tcpdump.

cloud networking (AWS/Azure) is a plus.

Automation/Scripting knowledge (Python, Ansible) preferred but not mandatory.

Experience

6 10+ years of strong experience in enterprise Network Security.

Experience working in large, distributed, high-availability environments.

Proven track record of leading install, upgrade, migration, and decommission projects.

Experience in handling major Incidents and RCA documentation.

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Soft Skills

Excellent communication and documentation skills.

Strong analytical and troubleshooting capability.

Ability to lead changes independently and collaborate with global teams.

Ability to mentor junior engineers.

Regards.

Rachana