IT Systems & Infrastructure Engineer - Security

Job Title – IT Systems and Infrastructure Engineer

Job Location – London (Piccadilly Circus)

Job ID – 39208

About this opportunity and L3Harris UK

Operating at 11 sites in the United Kingdom, L3Harris supports Britain's mission to secure and strengthen the country by delivering sovereign innovation across the space, air, land, sea and cyber domains.

L3Harris Trenchant is an elite global team of engineers and security researchers charged with building world-class computer security products. Trenchant’s expertise is the by-product of the L3Harris acquisition of two highly-regarded information security businesses – Azimuth Security and Linchpin Labs. United under Trenchant, we are a key component of L3Harris’ Intelligence & Cyber Division. We are a trusted, discrete partner furnishing security products, consultancy, training and integration services to allied security, defence, and law enforcement agencies.

A few of our employee benefits are:

• Hybrid working where possible, three days onsite per week


• 9/80 working schedule


• 25 days holiday per year (plus bank holidays), increasing with long service and with the opportunity to buy/sell up to 5 days


• Private medical insurance with optional family cover


• Pension scheme of up to 8% employer contribution


• Life Assurance 4x salary (flexible up to 10x)


• Group income protection


• Flexible opt-in extras such as a health care cash plan, dental insurance, gym membership, critical illness cover, cycle to work scheme, travel insurance and electric car scheme


• Employee Family Assistance Program providing mental health and wellbeing support


• Professional membership reimbursement (discretionary)

What the role will involve

The responsibilities of your role will include the following:

• Design, implement and support and improve a hybrid global network infrastructure, including routing, switching, firewalls, VPNs, and site-to-site connectivity.


• Automate infrastructure provisioning and management using tools such as Ansible, Terraform, Python, and Bash.


• Participate in incident response and serve as an escalation point for complex issues.


• Monitor system health and performance, using tools such as Prometheus, Grafana, and SNMP.


• Enhance infrastructure security through hardening, patching, and vulnerability remediation.


• Align IT services with global standards, and ensure stable, reliable infrastructure.


• Take ownership of problems and improve systems, processes, and service quality.


• Collaborate effectively with colleagues across regions and share knowledge.

What you’ll bring

The role requires the following experience and skills:

• Experiencing architecting, deploying and supporting global network solutions that support a wide variety of users.


• Experiencing building and support AWS networks.


• Experience with Infrastructure as Code (IaC) tools (Ansible, Terraform, Python, and Bash).


• Excellent communication and organizational abilities.


• Eligible to obtain a security clearance (current clearance highly regarded).


• Bachelor’s degree in a relevant field and 10+ years of experience in systems, network, or infrastructure engineering.

Preferred Additional Skills

• Experience with Juniper JunOS, Cisco IOS, and pfSense firewalls.


• Hands-on experience supporting linux, containerization and cloud platforms.


• Mentoring engineers and providing peer technical oversight.


• Ability to lead infrastructure projects.


• Experience supporting technical or engineering teams.


• Flexibility for occasional travel

Important to know

Due to the nature of our work many our roles require a UK nationality and the ability to obtain a security clearance. Applicants who accept a conditional offer of employment must meet the requirement of right to work in the UK and must meet eligibility requirements for access to classified information and will be subject to government security checks.

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