Network Engineer - Cisco ASA/Fortinet - Day Rate Contract

Network Engineer – Firewall & Data Centre Modernisation

Telefónica Tech | 6-Month Contract | Inside IR35

Telefónica Tech is seeking an experienced Network Engineer with deep firewall expertise to support a major Data Centre Modernisation programme. This contract role will focus on the migration of existing Cisco ASA firewall environments to FortiGate, delivering a like-for-like transition while identifying opportunities for optimisation and improvement.

You’ll work closely with internal engineering teams, vendors, and programme stakeholders, operating within a structured, ITIL-aligned environment and adhering to robust change and governance processes. This role requires strong hands-on capability, proven migration experience, and the ability to deliver in complex enterprise environments.

Key Responsibilities

• Perform 1-to-1 migrations from Cisco ASA to FortiGate firewalls, including: VPN configurations (site-to-site and remote access) VLAN and network policy migrations
• Analyse existing firewall rules and configurations, providing optimisation and improvement recommendations
• Develop clear, step-by-step migration runbooks and implementation instructions
• Execute firewall, VPN, and VLAN changes within agreed change windows (including out-of-hours where required)
• Ensure all activities align with agreed change management and governance processes
• Provide post-implementation support, including:
• Issue investigation and resolution
• Validation of migrated services
• Early-life / hypercare support
• Collaborate with programme teams, network architects, security teams, and external suppliers to ensure successful delivery of DC modernisation objectives