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

Worldwide | Oct. 20, 2026

Report as Closed

Company: IONOS

Country: Worldwide

Type: Remote

Employment: Full-time

Description:

About IONOS

At IONOS we don't just manage servers, we shape the digital future with our solutions for over 6.2 million customers worldwide. As Europe's leading hosting provider and pioneer of independent cloud solutions, we are building 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 companies. We work in agile teams, rely on transparent structures and believe that excellence and innovation can only be achieved with real 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 is agile: our team of experts in Berlin and Karlsruhe is constantly growing. In order to further strengthen this digital protective shield, we are looking for someone who is prepared to take on responsibility and actively shape the mission of our Defense Platform Services.

In this position, you are not a classic administrator in the background - you are the guarantee for the accessibility of millions of customers and form our digital protective shield. The Defense Platform Services team is responsible 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 control 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 will wage a dynamic game of cat and mouse against highly professional attackers. Where others capitulate to massive attack scenarios, you are just getting started - because your work determines 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 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 failures can occur.
• Innovation as a weapon: You use state-of-the-art technologies such as AI for log analysis and pattern detection to always be one step ahead of attackers and to implement new mitigation ideas in the team.
• Lifecycle Management: You will actively shape the operational architecture in an agile DevOps environment and ensure the constant evolution of our defense systems.
• Response phase: You take part in the essential on-call service (one week per month). This is not a mere duty, 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 combines deep technical knowledge with the vigilance of a defender. They see complex platforms as fortresses that do not tolerate any weakness.

• Experience & Seniority: You have 3-5 years of solid professional experience in platform operation of large infrastructures.
• Technical Stack: You are an expert in Linux (Debian/CentOS) and Nginx (Reverse Proxy/WAF). Ideally, you have mastered networking concepts such as BGP, Flowspec and Anycast and use automation tools such as Ansible, Puppet or Python as standard tools.
• Language competence: In our international environment you communicate fluently in English; Knowledge of German is a valuable advantage.

Benefits

• Hybrid working model.
• Flexible working hours through trust-based working hours.
• At some locations there is a subsidized canteen and various free drinks.
• Modern office space with very good transport connections.
• Various employee discounts for activities and products.
• Employee events such as summer and winter celebrations, as well as workshops.
• Numerous further training and development opportunities.
• Various health offers, such as sports and health courses.

Notes on the application

We value diversity and welcome all applications - regardless of e.g. 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 irrelevant criterion under applicable law.

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