Network Security Specialist

Salary: £61,000 - 91,000 per year

Requirements:

• Solid grasp of networking, security and monitoring.
• Experience and expertise in securing and protecting large ISP networks.
• Familiarity with network hygiene measures such as BCP38/84 anti-spoofing protection, RPKI, BGP routing BCPs, RIRs, Internet Routing Registries, DNS/DNSSEC, and domain registration.
• Strong understanding of network security vulnerabilities and protections, including denial of service attacks and mitigation, BGP hijacking, CoPP, access lists, Tacacs, spam, malware and abuse.
• Experience presenting findings and making recommendations to other operational teams.
• Experience working with multiple collaborators to improve security and incident response in an international environment.
• Demonstrated ability in an ISP environment and Internet security arena.
• Experience with Internet organizations such as RIRs and domain name registries, and tools like whois/RDAP, RIPE RIS, BGP and DNS monitoring.
• RIPE NCC certification in Database/BGP security is a plus.
• Solid understanding of network security, security monitoring and layers of defense principles.
• Fluency in English, both spoken and written.
• Superb communication skills.
• Extensive knowledge or interest in at least four of the following areas: networking, TCP/IP, IPv4/IPv6, BGP, RPKI, CoPP, DNS/DNSSEC, DOS protection and mitigation, security analytics, and monitoring/analytics solutions.
• Basic scripting, programming or database skills.
• Ability to prioritise effectively and work independently under pressure.
• Great teammate who can support internal and external working groups.

Responsibilities:

• Assure that our core and global tier-1 network has sound security protection and that product security is monitored.
• Work closely with our core network architects, engineering and operational teams, and global security teams to identify improvements and drive network hygiene security enhancements.
• Provide specialised skills during investigations.
• Translate security findings or deficiencies into security risks and advise the organization on blocking issues and acceptable risk.
• Identify and drive improvements in network security on the tier-1 core network.
• Advise our ISP networks to implement similar security measures and monitoring.
• Review, generate, translate, create and hand over technical specifications, documentation, monitoring use cases and playbooks to incident response teams.
• Act as a mentor, technical lead and escalation point for other engineers.
• Monitor and respond to incidents.
• Serve as an authority on Internet security topics such as network hygiene, MANRS, DDoS mitigation, BGP routing and traffic analysis.
• Trace and identify sources of BGP hijacks, BGP leaks, DDoS, malware and other abuse traffic.
• Review and improve security requirements in policies and guidelines to align with industry best practice.
• Identify potential areas of improvement and drive implementation.
• Liaise with the Global Security Operations Centre, internal and external operational teams, and other business units to set priorities for maximum effect.
• Work with external bodies such as M3AAWG, CableLabs, RIPE and other security and standards organizations to ensure our networks and services follow industry best practice.

Technologies:

• ARM
• Support
• Mobile
• Network
• RIS
• Security
• TCP/IP
• Grafana
• Splunk

More:

We are Liberty Global, a world leader in converged broadband, video and mobile communications and an active investor in cutting-edge infrastructure, content and technology ventures. Through our fibre-based and 5G investments, we provide over 85 million fixed and mobile connections and are rolling out the next generation of products and services. Our brands include Virgin Media-02 in the UK, VodafoneZiggo in the Netherlands, Telenet in Belgium, Sunrise in Switzerland, Virgin Media in Ireland and UPC in Slovakia. Liberty Global Ventures, our global investment arm, holds more than 75 companies and funds across content, technology and infrastructure. Our scale allows us to share knowledge across our operations and investments, and we are committed to diversity, equity and inclusion, as well as reducing our environmental impact. We offer competitive pay, a bonus, 25 days of annual leave with the option to buy 5 more, learning access through LinkedIn Learning and Coursera, company pension contributions, a Calm subscription in the Netherlands, public transport subscription in the Netherlands, a health insurance premium subsidy, and a company laptop, mobile and phone subscription. This full-time role is based in Amsterdam or London.

last updated 36 week of 2026