Network Engineer

Forsyth Barnes; Greater London; Hybrid; GBP 60,000 - 90,000; Part time

Job summary

Forsyth Barnes is seeking a Network Engineer/Designer for a 3-month contract to deliver project-based network and security changes. The role covers design, documentation, and implementation across hybrid cloud and on‑prem environments in a large retail setting.

You will work autonomously on deliverables, producing runbooks, migration notes, and verification reports while applying standards for routing, security, and cloud connectivity.

Qualifications

• Proven experience designing enterprise networks with routing and switching.
• Hands-on work implementing BGP in large environments.
• Familiarity with security zoning, VPNs, and cloud connectivity.
• Experience with Cisco ACI and policy-driven designs.
• Knowledge of Juniper Mist wireless and access networking.
• Understanding of Zero Trust and secure access patterns.
• Knowledge of Azure networking deployments.
• Ability to script and automate network tasks.

Responsibilities

• Produce high-quality network documentation: HLDs/LLDs, diagrams, specs.
• Contribute network designs for routing, segmentation, and cloud links.
• Update documentation across hybrid cloud and on‑prem environments.
• Implement configuration changes across firewalls and LTM devices.
• Build and validate IPsec VPNs, tunnels, and Zero Trust access.
• Configure Azure networking components and connectivity artefacts.
• Develop migration/runbooks and post-change records.
• Create runbooks, testing steps, and verification reports.

Skills

Routing & Switching

BGP (enterprise)

OSPF/VLAN/NAT/QoS/IPsec

Cisco ACI experience

Juniper Mist

Zero Trust concepts

Azure networking

Automation concepts

Python scripting

Terraform / IaC

Tools

Cisco ACI

Juniper Mist

Fortinet FortiGate

Palo Alto Networks

Zscaler ZIA/ZPA

Azure networking

F5 LTM

Terraform

Python

GitHub

Job description

Duration: 3 months initially, with potential extensions

Location: Hybrid / Remote

Role Overview

A Network Engineer / Network Designer is required to deliver project-based network and security changes within a large, distributed retail organisation. This role focuses solely on project delivery, with no BAU or operational support responsibilities.

The contractor will work under general direction, taking responsibility for their own deliverables and ensuring that all design output, configuration artefacts, and documentation updates are accurate, consistent, and aligned with established standards. The work will involve contributing to network designs, implementing planned configuration changes, and updating documentation across hybrid cloud and on‑premises environments.

Technologies include Cisco ACI, Juniper Mist, Fortinet FortiGate, Palo Alto Networks, Zscaler (ZIA/ZPA), Azure networking, F5 LTM, and automation tooling such as Python, GitHub, and Terraform.

Key Responsibilities

Network Design & Documentation

• Produce and update high‑quality network documentation, including HLDs, LLDs, diagrams, and configuration specifications.
• Apply established design patterns for routing, segmentation, cloud connectivity, and secure access.
• Document changes clearly and consistently, ensuring traceability across project phases.
• Contribute to designs for Cisco ACI, including application profiles, endpoint groups, and policy models.
• Contribute to documentation for Juniper Mist wireless and access network deployments.
• Prepare clear integration and connectivity documentation for Zscaler ZIA and ZPA.
• Deliver planned configuration changes across Fortinet, Palo Alto, and Juniper SRX firewalls.
• Implement routing changes using BGP and associated enterprise protocols.
• Build IPSec tunnels, VPNs, and Zero Trust access configurations following approved designs.
• Configure F5 LTM for application delivery and traffic management.
• Complete migration tasks, cutovers, and validation steps in line with project plans.
• Produce implementation runbooks, testing steps, and post‑change records.
• Deploy Azure networking components such as VNets, subnets, NSGs, UDRs, Azure Firewall, and Private Endpoints.
• Update cloud network diagrams and documentation to reflect changes and new deployments.
• Support the delivery of hybrid connectivity using VPN Gateway and ExpressRoute.
• Ensure cloud networking aligns with existing enterprise design standards.

Automation & Tooling

• Use Python to support automation of repeatable network configuration or verification tasks.
• Maintain configuration artefacts and documentation using GitHub version control.
• Apply Terraform modules to deliver network and cloud infrastructure builds where required.

Transformation & Migration Delivery

• Contribute to workstreams delivering network modernisation, cloud adoption, and segmentation changes.
• Follow defined procedures when supporting branch, cloud, or data centre migrations.
• Produce migration documentation, implementation notes, and verification reports.
• Identify risks or issues related to network changes and elevate appropriately.

Required Skills & Experience

Core Networking

• Strong understanding of routing and switching technologies.
• Practical experience implementing BGP in enterprise environments.
• Knowledge of OSPF, VLANs, NAT, QoS, and IPsec VPN.
• Experience working with Cisco ACI and policy-driven network designs.
• Familiarity with Juniper Mist wireless and access networking.

Security & Firewalls

Hands‑on experience with:

• Fortinet FortiGate
• Including policy creation, rule updates, segmentation, and configuration deployment.

Secure Access & Zero Trust

• Experience deploying Zscaler ZIA and/or ZPA into enterprise environments.
• Understanding of Zero Trust concepts and secure access patterns.
• Understanding of hybrid connectivity requirements and cloud security controls.
• Automation experience with Python, Terraform, GitHub, and/or Ansible.
• Experience configuring and maintaining F5 LTM.
• Experience working in large distributed or retail organisations.

The contractor will be responsible for delivering:

• Updated network documentation (HLDs, LLDs, diagrams).
• Configuration build documents for firewall, routing, and LTM implementations.
• Azure networking deployment artefacts and connectivity documentation.
• Migration runbooks, test plans, and implementation records.
• Accurate, fully maintained documentation within agreed repositories.
• Clear, complete handover material for operational teams.