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Senior Security Build Engineer

Date: 26-Mar-2021

Location: SLOUGH, GB

Company: Telefonica S.A.

Location(s):  Slough


We are O2, the commercial brand of Telefonica UK Limited, a leading digital communications company owned by Telefonica S.A. We put our 25 million UK customers at the heart of everything we do, so we can use our technology to connect them to the experiences they live for.


And just like our customers, we open up exciting possibilities for our employees too. Great benefits. Generous rewards. High-quality training. Ongoing career development. These are just some of the reasons to join us.


We’re always on the lookout for great talent, and we’re all about inclusivity. We want to be a true reflection of our customers and their communities, to help us make the best decisions. That’s why everybody’s welcome at O2 – it’s time to get everyone in the room.



About the team?

The IP Network Build Team is part of the Transport Domain which is responsible for connecting our mobile and fixed network equipment. They connect our people to the IT systems that they need to do their jobs. In particular the role of the Security Engineer ensures that this is all done securely and in line with Telefónica Security Policy. The IP Network Build team consists of highly skilled individuals who are responsible for all network and security build activity.


About the role?

The purpose of this role is to support security build activities in partnership with the Security Design Team within Telefónica UK. The role holder will deliver high and detailed level network security implementations for the build design of new security infrastructures which assist with the delivery of new functionality and service improvements.


The holder of this role will have build responsibilities for the security infrastructure; implementing network connections through firewalls and managing security build projects.


This role requires expert knowledge in a wide range of information security domains with a focus on network security technologies such as firewalls, intrusion prevention and remote access.


The holder of this role needs to be self-motivated, take initiative in suggesting improvements, possess excellent technical skills as well has have great leadership characteristics. They will need to be able to represent the team to senior figures within Telefonica. 


 Key Responsibilities:

Work with the Security Design Team and our Front Office Team to implement security projects as directed.

Implement authorised network connections on Firewalls as per the O2 Authority for Network Connection process.

Implementation of security infrastructure in line with the security architecture / framework. This includes:

  • Firewalls (Checkpoint, Juniper, Fortinet)
  • Network experience (Cisco, Juniper)
  • Remote Access Solutions
  • Web/URL Filtering Solutions
  • Intrusion Detection and Prevention Systems
  • Vulnerability Assessment


 What we need from you:


  • Qualified to CCSA
  • At least 3 years’ experience in working in a IP implementation environment
  • At least 1 years’ experience in working with firewalls
  • Good experience with Change Control processes
  • A strong understanding of IP and associated Protocols
  • Hands on experience with Checkpoint



  • Qualified to Fortinet NSE4
  • Hands on experience with Fortinet
  • Hands on experience with Juniper firewalls
  • Basic project management skills



Salary and benefits:

We’re looking to pay a competitive salary (depending on experience) for this position. We also offer plenty of extras to sweeten the deal, which could include things like bonuses, life assurance cover, health care, holiday entitlement and lots of flexible benefits. We also believe a great work-life balance is important, so we’re open to considering part time and flexible approaches to working. Like to know more? Feel free to raise it.


If you have any questions about the role then please email who will be happy to help.