Network Engineer

Overview

As our Senior Network Engineer, you will be responsible for designing, implementing, and securing complex network infrastructures across multiple sites and cloud environments. This role requires deep expertise in Fortinet, Cisco & other network technologies, with a strong focus on network security, SD‑WAN, and cloud networking. The engineer will lead operational activities, manage third‑party vendors, and oversee site setups, including mobile connectivity via 4G/5G and Starlink. A key part of the role involves team leadership, security posturing, and ensuring the resilience and compliance of all network services.

Responsibilities

• Design, deploy, and maintain LAN/WAN infrastructure across corporate offices, data centres and all Dalkia sites.
• Configure, manage, and troubleshoot network security appliances and firewalls, particularly Fortinet FortiGate.
• Maintain and optimise switching and routing environments.
• Support and enhance SD‑WAN solutions, ensuring high availability and performance across remote sites.
• Administer and troubleshoot complex BGP configurations and other routing protocols (OSPF, EIGRP).
• Oversee daily network operations tasks, including monitoring, patching, backups, performance tuning, and documentation.
• Collaborate with 3rd‑party vendors and service providers to ensure timely delivery of services, support, and escalation management.
• Ensure security best practices are applied across all network layers, participating in audits and remediation projects.
• Participate in the planning and execution of network upgrades, migrations, and disaster recovery procedures.
• Provide mentorship and act as a point of escalation for high‑severity incidents.
• Maintain detailed network documentation, including diagrams, IP schemas, and configuration standards.

Core Competencies

• Analytical – able to analyse data, draw out themes / trends to inform data‑driven decisions.
• Commercial Awareness – understands the importance of managing costs and expenses, applying the necessary controls.
• Communication – able to adapt style and approach to enable a diverse audience to connect with the messages and understand the purpose.
• Empathy and compassion – People First always.
• Discretion and ethics – mature attitude to managing confidential and sensitive information.
• Quick decisions – based on well‑reasoned thinking.
• Integrity.
• Risk Management – is aware of the impact on risk to the business and applies the necessary controls.
• Initiative – Proactively takes ownership of tasks while looking for opportunities to improve processes.
• Accountability – Takes responsibility for tasks and ensures accuracy and compliance with established procedures.
• Customer Service Orientation – Shows a customer‑centric approach to delivering services, providing timely and helpful support to Dalkia employees.
• Team Player – Ability to collaborate and work as part of a team and across the organisation.

Skills and Experience

• High degree of attention to detail and numerate.
• Strong experience with:
• Fortinet FortiGate firewalls (VPNs, IPS, UTM, HA)
• Fortinet Switches & Access Points
• Fortinet software and security services
• Cisco routers, switches, and wireless infrastructure (IOS, IOS‑XE, NX‑OS)
• HP Aruba switches
• Deep knowledge of network security principles, firewall rules, VPNs, VLANs, and NAC.
• Advanced configuration and management of FortiGate firewalls, FortiManager, FortiAnalyzer, and FortiSwitch.
• Deep understanding of Fortinet Security Fabric, including integration across endpoints, networks, and cloud.
• Proficient in Fortinet security policies, UTM features, and threat intelligence.
• Practical experience managing and supporting SD‑WAN, site setup, and mobile connectivity solutions.
• Proven experience with BGP, OSPF, and other dynamic routing protocols in complex multi‑site topologies.
• Experience with data centre networking and high‑availability designs.
• Comfortable leading incident response and conducting root cause analysis.
• Demonstrated leadership experience, including team management and vendor coordination.
• Licensing understanding and management.
• Solid understanding of network monitoring tools (e.g., SolarWinds, PRTG, or similar).
• Experience with ITIL processes and change management practices is a plus.
• Excellent organisation and administration skills.
• Good knowledge of Service Desk Management Systems.
• Have the ability to multitask and prioritise workload, while maintaining efficiency and quality of work.

Company Overview

Jointly owned by EDF Customers and Dalkia, we are a leading technical services group operating nationwide in the UK. Housing key expertise under one roof, we provide specialist technical services in technical facilities management, mechanical and electrical engineering, energy performance contracting and systems integration and digital services. We leverage the strength of our Group, without losing the personability of a smaller business. We are a people‑first culture. In fact, our customers tell us that we build the best people and customer relationships in the business. With an annual turnover of over £600 million, c. 5,000 employees and a diverse and inclusive ethos, we are proud to attract great talent, nurturing and inducting our people who embed the Dalkia DNA and apply an innovative mindset across all customer engagements.

Values and Culture

• People First – it starts with health, safety and wellbeing: We look out for each other – not just making sure we’re physically safe but we look after each’s wellbeing too.
• Better Together – a collaborative team: We work together, respecting and listening to each other’s point of view.
• Trusted Partners – dedicated to our client’s success: Our clients have to know they can rely on us, and we should continuously work on building great relationships with them.
• Taking Responsibility – making a positive difference: Being responsible employees, customers and people is also very important, we have the opportunity to make a positive difference for our immediate, and the wider, environment through our action.

Equity, Diversity and Inclusion

At Dalkia, we are committed to equity, diversity, and inclusion. We ensure that every applicant is treated fairly and respectfully throughout our selection process. If you require any adjustments, please inform us in confidence. Our talent acquisition team is here to assist you.

Benefits

• A competitive salary package
• We pay for professional memberships relevant to your role and invest in our people’s professional development
• Pension Scheme
• Life assurance
• 25 Days Holiday PLUS Bank holidays
• Cycle to work scheme
• Salary sacrifices electric vehicle scheme – where we help you lease an electric vehicle for a fixed monthly cost
• Access to our Benefits platform with a wide range of retail discounts.