Firewall Engineer – Level 2

About Proximus Luxembourg Proximus Luxembourg is a leading historical player in the ICT & Telecoms markets. Proximus Luxembourg addresses both residential and business markets through its commercial brands Tango, Proximus NXT and more recently Codit. With PSF support status, the company has almost 800 employees. All these experts share a passion for digital technology, a spirit of openness and innovation, and a desire to simplify, connect and make their customers' personal and professional activities ever more secure. Proximus Luxembourg is actively contributing to the acceleration of Luxembourg's digitalisation and its economic influence through the development of connectivity, resilient infrastructures and 5G, as well as innovative technologies such as Blockchain, Artificial Intelligence, Machine Learning and IoT. Proximus Luxembourg is a subsidiary of the Proximus group (Euronext Brussels: PROX), provider of digital services and communication solutions operating in the Belgian and international markets. About Proximus NXT Proximus NXT Luxembourg supports all organizations in their digital transformation, by providing holistic ICT & Telecommunication solutions, as well as tailored managed services. With our partners and customers, we co-create opportunities and enable growth in a secure and sustainable manner. As a result of our unique expertise in next-gen IT services, mobile and advanced connectivity, we help our customers achieve their ambitions and realize their vision. Together with them and our partners we implement sovereign and trusted solutions that make people work smarter.– www.proximusnxt.lu Your mission: Domain: Network Security / Firewall Services On-Call: Yes (Level 2 rotation) The Level 2 Firewall Engineer ensures the stability, security, automation, and continuous improvement of the enterprise firewall infrastructure. The engineer handles complex incidents and problems, designs and maintains automation for firewall lifecycle operations, and ensures all configurations align with the CMDB as the authoritative Source of Truth. The role bridges operational excellence and infrastructure engineering, applying DevOps principles to security infrastructure.

Key Responsibilities
Incident & Problem Management (Level 2 Scope)
- Handle escalated incidents from Level 1
- Troubleshoot complex firewall issues (routing, NAT, clustering, performance)
- Perform deep packet analysis when required
- Conduct root cause analysis (RCA)
- Identify recurring issues and open Problem records
- Participate in post-mortem analysis and improvement plans
- Participate in Level 2 on-call rotation Firewall Engineering & Automation
- Design and maintain automation for:
- Software upgrades (CheckPoint, Fortinet, Open-Source)
- Cluster upgrades and failover validation
- Policy deployment pipelines
- Backup & restore procedures
- Implement infrastructure changes through:
- Ansible / AWX
- Git-based workflows
- CI/CD pipelines
- Ensure infrastructure changes are reproducible and version-controlled
- Contribute to Git repositories and review pull requests
- Maintain configuration as code principles Configuration Governance & CMDB Integrity
- Ensure all firewall objects and rules align with CMDB data
- Enforce Source of Truth model (e.g., NetBox or equivalent)
- Avoid manual configuration drift
- Implement validation checks before deployment
- Contribute to compliance reporting Firewall Platform Expertise Check Point Software Technologies
- R8x architecture
- Management Server / MDS
- SmartConsole
- ClusterXL
- Policy installation & troubleshooting Fortinet
- FortiGate
- FortiManager
- HA clusters
- Security Fabric integration Open-Source Firewalls
- nftables / iptables
- pfSense
- OPNsense
- Strong understanding of Linux networking stack DevOps & Engineering Practices
- Infrastructure as Code mindset
- CI/CD pipeline integration
- Unit testing for automation scripts
- Use of Git branching strategies
- Observability integration (logs, metrics, alerts)
- Secure coding practices for automation Upgrade & Lifecycle Management
- Plan and execute:
- Major version upgrades
- Hotfix deployment
- Security patching
- Automate pre-checks and post-checks
- Maintain upgrade playbooks
- Document rollback strategies Security & Compliance
- Ensure firewall configurations align with security policies
- Support audit evidence collection
- Support vulnerability remediation
- Ensure secure configuration standards, and best practices
- Participate in security hardening initiatives

Your profile
Technical Skills Required Mandatory
- 5+ years in enterprise firewall engineering
- Strong knowledge of:
- CheckPoint R8x
- FortiGate
- Solid understanding of:
- TCP/IP
- Routing (BGP, OSPF basics)
- NAT
- VPN technologies
- Experience with Linux networking
- Experience with automation (Ansible preferred)
- Git proficiency
- Strong troubleshooting skills Nice to Have
- Experience with containerized firewall deployment
- API-driven firewall configuration
- Experience with CI/CD tools (GitLab CI, etc.)
- Experience integrating firewalls with cloud (AWS)
- Experience in high-availability architectures Soft Skills
- Analytical mindset
- Ability to perform structured RCA
- Autonomous and proactive
- Strong documentation discipline
- Ability to mentor Level 1 engineers
- Clear communication during incident bridges Our offer:
- A professional, stimulating and innovative working environment: Joining Proximus Luxembourg means becoming part of a human-sized company while benefiting from the strength, expertise and opportunities offered by the Proximus Group. You will work within dynamic, supportive and collaborative teams, where team spirit, knowledge sharing and innovation play a central role.
- Genuine career opportunities within the Proximus Group: You will have the opportunity to develop your career within Proximus Luxembourg and the Proximus Group, both nationally and internationally. Thanks to the diversity of our activities, internal mobility opportunities and an environment that encourages continuous learning, you will be able to strengthen your skills and grow your expertise in innovative fields such as cloud, data, artificial intelligence, telecommunications and emerging technologies. You will benefit from personalized support and tailored training programs to support your professional development.
- An attractive remuneration package and benefits that support your work-life balance: Your salary is defined according to a clear salary framework, taking into account your professional experience, skills and seniority. The recruiter will share the applicable salary range with you before the first interview. You will also benefit from flexible

working hours
with the possibility of teleworking, as well as numerous

benefits:
meal vouchers, the possibility of a company car, “quality time” dedicated to supporting your work-life balance (4 hours per month), additional days of leave linked to our collective agreement, sports and well-being activities, and much more.
- A company committed to diversity and inclusion: Proximus Luxembourg promotes equal opportunities and provides an inclusive environment where everyone can thrive and develop their full potential. Our multicultural teams, representing 34 nationalities, reflect the richness of our company culture. As part of the recruitment process, a criminal record extract may be requested. Your personal data is processed in accordance with applicable data protection regulations.