Network Engineer (L3 - 3rd Line)
Confirmed on the employer's own hiring board on Sep 25, 2026. First seen by Alion on Sep 3, 2026. Telefónica Tech scores A on the Alion truth index.
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 everyday 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, Enterprise Applications, Digital Workplace, Cyber Security & Networking.
Values: Open, Bold, Trusted
Trusted Partners:
- Microsoft: Top 3 Service Providers, Azure Expert Status, Fastrack & Inner Circle Partner
- HPE: Platinum Partner - FY23 UK&I Solution Provider of the Year
- Fortinet: Elite VIP Program - one of only 2 in the UK
- Palo Alto & Crowdstrike: part of our NextDefense Cyber Security Portfolio
The L3 Network Engineer is responsible for management, maintenance and support of datacentre network infrastructure, perimeter security systems and management platforms.
Key Responsibilities:
- Supporting datacentre network and security infrastructure (LAN / WAN / WLAN / Firewalls / Application/VPN, Delivery Controllers etc.)
- Troubleshooting complex network issues, identifying network bottlenecks, and implementing solutions to ensure optimal network performance
- Optimizing network infrastructure to ensure maximum performance and scalability.
- Maintain accurate network documentation, including network diagrams, configurations, and inventory records
- Day-to-day patching, maintenance and operation of the above in secure environments
- Continual improvement of the systems based on changing demands
- Liaising with various departments within the business
- Coordinating with 3rd party suppliers and partners to support, maintain and implement these systems
In addition to the above duties and responsibilities the post holder must be prepared to undertake such additional duties which may result from changing circumstances, but which may not of necessity change the general character or level of responsibility to the post.
Essential;
- Extensive experience of enterprise datacentre/LAN/WAN network management
- Extensive experience of Cisco ACI, switching, routing
- Extensive experience of Cisco and/or Fortigate firewalls
- Extensive experience of network monitoring, troubleshooting and management tools
- CCNP certification
Desirable;
- Fortinet certification
- Aruba certification
- Juniper Certification
Interpersonal Skills;
- Articulate and a clear communicator
- Be a customer advocate
- Have the ability to converse technical terms and definitions to non-technical personnel
- Experience in report writing
- Meticulous with excellent attention to detail
- Interested in Continual Service Improvement
- Able to multitask and handle large amounts of complex information
- Must have the right to live and work in the UK.
- Due to our location, access to own transport is essential.
- Must meet Security Clearance vetting requirements as this is a requirement of the role.
- Any offer would be conditional upon the successful candidate passing a full SC and NPPV3 vetting process.
Key Words:
Network Engineer - CCNP - Fortinet - Fortigate - Firewalls - Cisco ACI - Networking - Cisco - Virtual Networking - Data Centre - Data Center - SDN
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.