Systems Administrator

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We’re London’s largest and fastest 100% full fibre broadband provider, bringing better internet to Londoners since 2013. Unlike most providers, we build, own and operate our dedicated fibre optic network and install it directly into the home, meaning we can deliver a super-fast connection at prices the national providers find hard to beat. We’re a relatively new company to the market, but since establishment:

• We’re the only provider in London offering residential broadband speeds of up to 5Gbps.

• Our network covers 1.3 million properties in London, which is more than one third of homes in the UK’s capital city.

• We have over 800,000 properties under wayleave agreement and are currently working in partnership with more than 200 of London’s biggest landlords.

• We have connected 720 community spaces in 24 boroughs, giving more Londoners free access to fast, reliable broadband.

We’re proud of our achievements so far, but we are not complacent and definitely not stopping here. To help us get to our future, we’re looking for forward thinkers, people with big ideas, people passionate about technology and most importantly hard working team players to join us and be a part of our growing business.

Job purpose:

• The Systems Administrator will be responsible for the day-to-day management, security, maintenance and compliance of the organisation's internal infrastructure platforms.

• Be part of project teams as required to renew current systems and deploy new solutions.

• Ensure that all internal infrastructure remains secure, supported, patched and compliant with the organisation's security policies and UK Telecommunications Security Act (TSA) requirements. See Regulation 12 / Chapter 11 – Patching & Updates of the TSA supporting the o organisation's ongoing external security and TSA audits as required.

• Diagnose, troubleshoot and resolve software, hardware and infrastructure-related network issues, working with Network Engineering and Network Operations teams as appropriate.

• Ensure that operating systems, applications, infrastructure platforms and supporting services are maintained with current security patches, vendor bug fixes and security updates.

• This is a proactive, hands-on role focused on preventing security and compliance issues rather than simply responding to them.

What you’ll be doing:

Proactive Systems Administration

• Install, configure and maintain software, hardware and operating system features and policies in support of the Network Engineering and Operations function.

• Ensure proper and secure storage, backup and retrieval of systems and data.

• Identify areas for improvement, end-of-life notifications and other systems issues.

• Assist the Network Operations Centre on complex/pervasive problems.

• Replacement of failed components on-site as required.

• Ensure that documentation is updated according to company requirements.

TSA, Security & Compliance

• Own the operational infrastructure activities required to maintain compliance with UK Telecommunications Security Act (TSA) requirements and associated security obligations.

• Ensure operating systems, applications and infrastructure platforms receive security patches, vendor bug fixes and firmware/software updates within agreed timescales and defined security and hardening standards.

• Monitor vendor security advisories and vulnerability notifications and assess their relevance and impact.

• Identify and remediate vulnerabilities across the infrastructure estate based on risk and defined remediation SLAs.

• Ensure infrastructure remains within supported vendor versions and identify end-of-life or unsupported systems.

• Work closely with the Security, Network Technology and IT teams to identify and address security risks.

• Support security incident investigations and remediation where infrastructure is involved.

• Ensure appropriate logging, monitoring and alerting is implemented across managed infrastructure.

• Maintain secure configuration baselines and ensure systems remain aligned with them.

• Comply with all external audit and assurance requirements as required in TSA regulations.

The experience we’re looking for you to bring:

The Engineer should have a minimum of 5 years of experience working in a server, storage and a networking environment.

Must have:

Strong hands-on experience maintaining, troubleshooting, securing and patching:

• DNS – strong understanding of DNS architecture, zones, records, recursion, authoritative DNS, DNS security and DNS troubleshooting. Experience with BIND or equivalent DNS platforms.

• DHCP – administration, configuration, troubleshooting and patching of DHCP services, including high-availability configurations.

• NTP – administration and maintenance of NTP services, including secure time synchronisation and troubleshooting of time drift and synchronisation issues.

• NetBox / IPAM / DCIM – administration, maintenance, upgrades and integration with network automation and source-of-truth processes.

• Ability to assess vendor security advisories and determine the appropriate patch, software upgrade or mitigation required for these platforms.

• Experience planning, testing and implementing infrastructure upgrades while minimising service disruption.

Security & Patch Management

• Strong understanding of infrastructure vulnerability and patch management.

• Proven experience maintaining systems against defined security patching SLAs including via automation.

• Ability to identify, assess and remediate security vulnerabilities and software defects.

• Experience applying vendor security patches, bug fixes, maintenance releases and major software upgrades.

• Ability to manage emergency security updates for critical vulnerabilities.

• Experience maintaining evidence of patching and remediation for TSA, security and external audit compliance.

• Understanding of security hardening and secure configuration baselines.

• Experience using vulnerability management/scanning platforms such as Tenable, Qualys or equivalent.

• Understanding of CVEs, CVSS scoring and vulnerability risk assessment.

• Ability to document and manage patching exceptions where immediate remediation is not possible.

Nice to have:

• Familiarity with logging platforms and event correlation.

• Experience with data replication, backup, and recovery strategies.

• Next generation firewall experience

• Scripting Languages – e.g. Bash and Python

Tech stack:

• DNS (ISC BIND)

• DHCP (ISC Kea, FreeRadius)

• Palo Alto

• Dell PowerEdge and PowerVault, HPE ProLiant, Supermicro

• Elasticsearch/OpenSearch, Logstash, Filebeat

• NetBox

• Ansible

• Virtualisation

• AWS

• Puppet

• Terraform

• Linux Operating Systems

• Databases – e.g. NoSQL, MySQL, PostgreSQL

Why join us:

• You get to work with some of the best technology in the market

• Be part of an exciting scale up business where you can bring your ideas, bring your knowledge, we value your contribution

• We all love time off whether that’s going on an exotic holiday or a staycation, you’ll get 25 days holiday to enjoy, increasing by 1 day for each year of service up to 28 days

• Birthday leave, our treat to you

• Keen cyclist, join our cycle to work scheme

• Flexible WFH policy

• Enjoy the perks of Private Health Cover

• You get to work with an amazing bunch of people

What happens next:

You’ve done your bit so sit back and relax, we will review your application and come back to you.

If we think you’re not quite right for the role you have applied for but may be a better fit for another, we’ll definitely let you know.

Want to know more about a career at CFL, check out our careers page:

We are an Armed Forces friendly organisation.

We are an equal opportunities employer that values diversity in our team, we welcome applications from all backgrounds.