Mission freelance Senior Network Security Engineer(h/f)

We are looking for an experienced Senior Network Security Engineer to join a team responsible for securing and maintaining critical enterprise network infrastructures. This role focuses on firewall administration, network traffic filtering, security policy enforcement, incident management, and cloud network segmentation. The successful candidate will contribute to both operational activities and strategic security initiatives while ensuring compliance with security standards and regulatory requirements.Main Responsibilities

• Review, validate, and implement network access and firewall requests in accordance with security policies.

• Configure, maintain, and optimize firewall rules across complex enterprise environments.

• Investigate and resolve network security incidents, connectivity issues, and policy-related disruptions.

• Provide technical expertise and guidance for infrastructure, security, and transformation projects.

• Ensure security controls and firewall configurations remain aligned with organizational security standards and industry best practices.

• Maintain accurate documentation of security configurations, network flows, and operational procedures.

• Conduct detailed traffic-flow analysis and support audit, compliance, and recertification activities.

• Contribute to continuous improvement initiatives aimed at strengthening security posture and operational efficiency.

• Collaborate with cross-functional teams operating in Agile environments.

• Minimum 5 years of hands-on experience in network security and firewall administration.

• Strong experience implementing and managing firewall policies and access controls.

• Proven track record in troubleshooting and incident resolution within enterprise environments.

• Experience with leading firewall technologies such as Palo Alto Networks and/or Fortinet.

• Familiarity with IT Service Management platforms, including ServiceNow or equivalent solutions.

• Solid understanding of networking, security architecture, and enterprise infrastructure principles.

• Experience with reporting automation, scripting, or data analysis using Python, VBA, or similar tools.

• Firewall administration and policy optimization.

• Intrusion Detection and Prevention Systems (IDS/IPS).

• Cloud security and micro-segmentation technologies.

• Network security architecture and traffic-flow analysis.

• Incident, problem, and change management processes.

• Security compliance, governance, and audit support.

• Automation and reporting solutions.

Participation in an on-call rotation may be required. Experience in large-scale, highly regulated, or mission-critical environments is considered an advantage.