Network Engineer - Cisco ASA/Fortinet - Day Rate Contract

Telefónica Tech (part of the Telefónica Group) is a leading NextGen Tech solutions provider with a highly diversified team of over 6,000 exceptionally skilled employees and +60 nationalities. 

We serve more than 5.5m customers every day in over 175 countries, with a global ecosystem of market-leading partners. Global strategic hubs: Spain, Brazil, the UK, Germany. 

The Telefónica Tech UK&I hub has an end- to-end portfolio of market leading services and develops integrated technology solutions to accelerate digital transformation through: Cloud, Data & AI, AI Business Solutions, Workplace Services and Cyber Security & Networking. 

Values: Open, Trusted and Bold 

 

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

 

Required Skills & Experience

• Expert, hands-on experience with Cisco ASA and Fortinet (FortiGate) firewalls
• Strong background in firewall architecture and enterprise network design
• Proven expertise in:
• High Availability (HA) firewall configurations
• Physical and virtual firewall deployments
• Advanced understanding of:
• Firewall rule design and optimisation
• VPN technologies (site-to-site and remote access)
• VLANs, routing, and network segmentation
• Experience with Cisco and Fortinet VPN solutions
• Demonstrable experience delivering firewall migrations in enterprise or data centre environments
• Experience working with Cisco ACI networks
• Solid understanding of ITIL processes and change management
• Desirable
• Relevant certifications such as:
• CCNP or CCIE
• Fortinet NSE4 (or higher)
• Experience on large-scale infrastructure or data centre transformation programmes
• Exposure to enterprise security best practices and network hardening

This is an excellent opportunity to play a key role in a high-profile transformation programme within a leading technology organisation. If you’re a hands-on Network Engineer with strong firewall migration experience and thrive in structured, enterprise environments, we’d love to hear from you.

Ready to Make an Impact?

Join us in shaping the future of digital transformation at Telefónica Tech UK&I. Be part of a team that values your expertise, supports your growth, and fosters a positive work environment. Apply now to embark on a rewarding journey!

We encourage applications from a wide range of individuals, irrespective of: age, disability, gender, gender reassignment, marriage and civil partnership, pregnancy and maternity, race, religion or beliefs and sexual orientation.

We look forward to hearing from you!

At Telefónica Tech, we believe inclusion is the bridge that empowers everyone to be their authentic selves. We celebrate and respect our differences because diversity drives innovation and makes us stronger.

 

Be yourself with us, and feel that you belong. 

We welcome applicants from all backgrounds and identities regardless of age, disability, gender reassignment, marital or civil partnership status, pregnancy or maternity, race, religion or belief, sex, and sexual orientation. 

 

We are also committed to equity, accessible hiring practices, and creating an inclusive culture through many means including TogetHer (Women's network) and our Employee Resource Groups which include Diversity and Inclusion, Telefónica Tech Pride, Neurodiversity, ELEVATE (African and Caribbean heritage network), and Sustainability.

 

 We don’t believe hiring is a tick box exercise, so if you feel that you don’t match the job description 100%, but would still be a great fit for role, please get in touch.