Senior Network Engineer

Trellint UK; Portsmouth; Hybrid; GBP 65,000 - 95,000; Full time

Benefits offered by this job

Remote-first flexibility

Hybrid or on-site options

Occasional travel

Job summary

Trellint UK is seeking a Senior Network Engineer to lead the design, deployment, and support of enterprise network infrastructure across our UK data center and office environments. You’ll own network solutions for data center networking, load balancing, and core services to ensure high availability and security.

The role involves mentoring engineers, coordinating with IT leadership, and delivering secure, reliable services.

Qualifications

• Bachelor’s degree in Computer Science, Computer Information Systems, or related field.
• CCNP, CCIE, CISSP or equivalent preferred.
• 7+ years of enterprise network engineering experience.

Responsibilities

• Lead design, implementation, and support of enterprise network infrastructure across UK data centers and offices.
• Architect solutions and mentor team members.
• Ensure high availability, performance, and security of core network services.
• Deploy FortiGate firewalls and FortiADC load balancers with HA configurations.
• Configure Dell L2/L3 switching and routing (OSPF).
• Provide secure VPN access for admin and operational use.
• Participate in incident response and root-cause analysis.
• Align network controls with ISO 27001 and Cyber Essentials Plus.

Skills

Core Networking

TCP/IP

Routing

Switching

VLANs

FortiADC

FortiGate

VPN

Education

Bachelor’s degree

Tools

Dell switches

Job description

As a Senior Network Engineer, you will lead the design, implementation, and support of enterprise network infrastructure across our UK data center and office environments. This role is focused on data center networking, load balancing, and core network services, ensuring high availability, performance, and security across all platforms.

Job Description:

Are you a seasoned network professional ready to lead the design, implementation, and evolution of enterprise network infrastructure? We are seeking a Senior Network Engineer to drive the planning, deployment, and optimization of our critical IT and security platforms. In this role, you’ll architect solutions, mentor team members, and ensure the seamless delivery of secure, reliable services across the organization.

About Us:

Join a forward-thinking company committed to pushing the boundaries of technology and driving innovation. Our team is made up of passionate individuals who thrive in a collaborative environment and are dedicated to shaping the future of our industry.

Your Role:

As a Senior Network Engineer, you will lead the design, implementation, and support of enterprise network infrastructure across our UK data center and office environments. This role is focused on data center networking, load balancing, and core network services, ensuring high availability, performance, and security across all platforms.

What You’ll Do:

• Proactively identify operational risks, performance issues, and security gaps within network and infrastructure environments
• Monitor trends, alerts, and emerging technologies to support continuous improvement of network reliability and security
• Contribute technical input to infrastructure and network strategy under the direction of IT leadership
• Network Design & Implementation
• Design, configure, and support enterprise network infrastructure across UK-based data centers and offices
• Implement and maintain FortiGate firewalls, including policies, NAT, and high-availability configurations
• Deploy and support FortiADC load balancers, including application delivery, traffic distribution, and high-availability designs
• Configure and manage Dell L2/L3 switching environments, including VLANs, trunking, and inter-VLAN routing
• Design and maintain core routing architecture using protocols such as OSPF
• Provide secure VPN access into the data center for administrative and operational access
• Operations & Troubleshooting
• Provide advanced troubleshooting across routing, switching, firewalls, and load balancing platforms
• Support network monitoring, logging, and alerting to ensure high availability and performance
• Participate in incident response and root cause analysis for network-related outages
• Security & Compliance
• Implement and maintain network security controls aligned with ISO 27001 and Cyber Essentials Plus
• Ensure proper segmentation, VLAN design, and access controls across environments
• Support audit activities through documentation, configurations, and evidence collection
• Change Management & Documentation
• Support network connectivity for co-located UK data center environments
• Manage cross-connects, switching infrastructure, and carrier handoffs
• Ensure resilient and redundant network designs aligned to production requirements
• Fortinet Firewalls (FortiGate)
• FortiADC (load balancing and application delivery)
• Dell networking (Layer 2 / Layer 3 switching platforms)
• Routing (OSPF)
• VLAN design and network segmentation
• Layer 2 / Layer 3 switching

What You Bring to the Role:

Education:

• Bachelor’s degree in Computer Science, Computer Information Systems, or related field.
• Relevant certifications such as CCNP, CCIE, CISSP, or equivalent are preferred.

Experience:

• 7+ years of enterprise network engineering experience in data center-centric environments
• Strong hands-on experience with:
• Deep experience with:
• Experience supporting high-availability network architectures
• Experience supporting ISO 27001 and Cyber Essentials Plus compliance environments
• Experience working in 24x7 production environments with on-call responsibilities

Skills:

• Core Networking
• Advanced TCP/IP networking fundamentals
• Routing, switching, VLANs, and segmentation
• Dell switch configuration and troubleshooting
• FortiADC configuration and support
• Traffic distribution, persistence, health checks, and high availability
• Firewall & Security
• FortiGate configuration, NAT, policy management, logging, and high availability
• Network segmentation and access control
• Connectivity
• Secure remote access via VPN for administrative and operational use

This position offers remote-first flexibility, with hybrid or on-site options available. Occasional travel to offices or vendor sites may be required based on project needs.

Why You’ll Love It Here:

• Strategic Impact: Lead mission-critical IT projects with direct visibility to senior leadership.
• Ownership & Autonomy: You’ll own the project plan — and the outcome.
• Collaborative Team: Work closely with experienced IT, business, and R&D professionals who value structure and results.
• Flexibility & Growth: Enjoy a flexible work environment with room for continued professional development.

We are committed to building a diverse and inclusive team where everyone feels empowered to contribute and grow. If you meet most of the qualifications and are excited about the role, we encourage you to apply.