Senior Network Security Engineer F5

Mission Overview: Keystone Solutions is seeking a Senior Network Security Engineer with expertise in F5 to ensure the security of applications and IT environments amidst the challenges of digital transformation. This consultancy mission will take place on-site at our client’s location, where you will represent Keystone Solutions.

Responsibilities:
As a consultant, you will be responsible for managing, securing, and continuously evolving the F5/AWAF infrastructure, while also monitoring and evaluating the security status of IT systems. You will be expected to intervene effectively in crisis situations. Key Deliverables:
• Installed, configured, and managed F5 / Advanced Web Application Firewall infrastructure.
• Developed, documented, and monitored the application of security policies.
• Conducted technical risk analyses on various IT systems.
• Implemented solutions to address identified vulnerabilities.
• Provided recommendations on technical solutions for securing partner connections (intranet/internet).
• Produced technical documentation and incident/crisis reports. Main Tasks:
• Manage the F5 Security infrastructure: F5, Advanced Web Application Firewall.
• Perform installations, configurations, and management of F5
- AWAF.
• Develop, document, and monitor the application of security policies.
• Continuously monitor and evaluate the security status of IT systems against malicious actions.
• Effectively intervene in crisis situations (organized attacks, network intrusions, virus detection, etc.).
• Advise on technical solutions for securing connections with external partners via intranet and internet.
• Conduct technical risk analyses for management purposes on various IT systems.
• Implement solutions to address potential vulnerabilities. Key

Skills:
• Installation, configuration, and management of F5 AWAF infrastructure (APM, ASM, LTM, Identity Provider, SSL VPN).
• Continuous monitoring and evaluation of system security status; crisis management (attacks, intrusions, viruses).
• Technical risk analysis and remediation of vulnerabilities.
• Knowledge of network and application firewalls (Palo Alto, Forcepoint, Panorama) and VPN/proxy solutions.
• Rigorous documentation and clear communication to teams and management. Communication and Collaboration:
• Strong written and verbal communication skills; able to document work clearly (reports, documentation).
• Ability to work in a team; methodical, precise, and client-oriented approach.
• Bilingual preferred (French, Dutch) or sufficient basic knowledge of a second national language; technical English is essential. Level and

Experience:
• Expert and autonomous execution under general direction (SFIA level 4 – Enable), senior technical profile.
• Minimum 5+ years of experience in IT security, autonomy, initiative, and ability to intervene effectively in crisis situations; explicitly not a junior role.

Education:
• Graduated or licensed in computer science or electronics, or equivalent through proven experience. Practical Information:
• Status: Recruitment / external mission.
• Responsibility Level: SFIA level 4 – Enable (senior technical).
• Reports to: Network & Security Team Leader.
• Work Regime: Full-time; remote work possible.
• Team: Network & Security team, in collaboration with systems, operations, and project teams. If you are ready to tackle technical and strategic challenges in a dynamic consultancy environment, apply today at Keystone Solutions Career Portal. Duration: 01/11/2026
- 31/12/2026 2 months
• (full time) Skills required:
• Firewalls et filtrage : routeurs, firewalls stateful packet inspection, firewalls applicatifs (Palo
- Level: Confirmed
- Most recent: Any time
• Outils de monitoring et corrélation de logs (Splunk, Nessus, Elastic SIEM)
- Level: Confirmed
- Most recent: Any time
• Protocoles et sécurité réseau : TCP/IP, HTTP/HTTPS, SSL, SNMP
- Level: Confirmed
- Most recent: Any time
• Sécurisation des réseaux sans fil (WiFi, WEP, WPA, WPA2) et principes de chiffrement (clé publique/p
- Level: Confirmed
- Most recent: Any time
• Solutions VPN (remote access et site-to-site) et Web proxy ; solutions terminal-serveur (Citrix)
- Level: Confirmed
- Most recent: Any time Language

requirements:
Dutch Level Active knowledge English Level Active knowledge French Level Active knowledge