Linux System Administrator (f/m/d) Defense Products

About IONOS

At IONOS, we don't just manage servers; with our solutions, we shape the digital future for over 6.2 million customers worldwide. As Europe's leading hosting provider and a pioneer for independent cloud solutions, we are building a next-generation infrastructure: from sovereign cloud architectures and high-performance GPU clusters to integrated AI automation tools.

What drives us: Digital freedom of choice for Europe and real impact for small and medium-sized enterprises (SMEs) as well as large corporations. We work in agile teams, rely on transparent structures, and believe that excellence and innovation only arise through true team spirit.

Ready for your next step? Become a part of IONOS and grow with us.

We live a culture of open structures and friendly cooperation, characterized by an unconditional team spirit. Our Defense team operates across locations and agily: our expert team is steadily growing in Berlin and Karlsruhe. To further strengthen this digital shield, we are looking for a personality who is ready to take on responsibility and actively help shape the mission of our Defense Platform Services.

In this position, you are not a classic administrator in the background – you are the guarantor of availability for millions of customers and form our digital shield. The Defense Platform Services team bears the responsibility for ensuring the existence of the digital infrastructure of the entire group.

Your mission is "Active Defense". You operate in a high-stakes environment and manage an infrastructure of around 800 components to neutralize threats in real time. As part of an elite unit of Site Reliability Engineers and Network Engineers, you engage in a dynamic cat-and-mouse game against highly professional attackers. Where others capitulate in the face of massive attack scenarios, you are just getting started – because your work decides on the availability of the European web.

Responsibilities

Your daily work is the precise response to the permanent threat situation: you balance the highly available operation of our scrubbing platforms with the constant further development of our defense strategies.

Platform Design: You administer and optimize complex, Linux-based proxy and defense infrastructures at the highest level.

DDoS Mitigation: You actively analyze attack patterns and implement precise countermeasures before outages can occur.

Innovation as a Weapon: You use state-of-the-art technologies such as AI for log analysis and pattern detection to always stay one step ahead of attackers and implement new mitigation ideas within the team.

Lifecycle Management: You actively help shape the operating architecture in an agile DevOps environment and ensure the steady evolution of our defense systems.

Response Phase: You participate in the essential on-call duty (one week per month). This is not a mere obligation, but the phase in which you, as the primary defender, intervene immediately to prevent massive outages.

Qualifications

We are looking for a Linux expert with the "security gene" – a professional who pairs deep technical knowledge with the vigilance of a defender. You understand complex platforms as fortresses that tolerate no vulnerability.

Experience & Seniority: You have 3-5 years of sound professional experience in the platform operation of large infrastructures.

Technical Stack: You are an expert in Linux (Debian/CentOS) and Nginx (Reverse Proxy/WAF). Ideally, you master networking concepts such as BGP, Flowspec, and Anycast and use automation tools such as Ansible, Puppet, or Python as standard tools.

Language Proficiency: In our international environment, you communicate fluently in English; German skills are a valuable advantage.

Benefits

Hybrid working model.

Flexible working hours through trust-based working hours.

At some locations, a subsidized canteen and various free drinks.

Modern office spaces with very good transport connections.

Various employee discounts for activities and products.

Employee events such as summer and winter parties, as well as workshops.

Numerous training and development opportunities.

Various health offers, such as sports and health courses.

Note on Application

We value diversity and welcome all applications – regardless of, e.g., gender, nationality, ethnic and social origin, religion, disability, age, as well as sexual orientation and identity, physical characteristics, marital status, or any other non-relevant criterion under applicable law.