Senior Network Security Engineer F5

Keystone Solutions; Brussel Hoofdstad; Hybrid; EUR 90,000 - 130,000; Full time

Job summary

Keystone Solutions in Brussels is seeking a Senior Network Security Engineer with deep F5 expertise to secure applications and IT environments during digital transformation. You will manage the F5 AWAF infrastructure, develop and monitor security policies, perform risk analyses, and intervene in crisis situations.

This on-site consultancy role reports to the Network & Security Team Leader, with the possibility of occasional remote work.

Qualifications

• 10+ years IT security experience; senior, autonomous.
• Experience securing F5/AWAF environments.
• On-site Brussels availability.

Responsibilities

• Manage F5 Security infrastructure (F5 AWAF).
• Install, configure, and manage F5 AWAF.
• Develop, document, and monitor security policies.
• Continuously monitor security status of IT systems.
• Intervene effectively in crisis situations (attacks, intrusions).
• Advise on securing connections with external partners (intranet/internet).
• Conduct technical risk analyses for management.
• Implement solutions addressing vulnerabilities.

Skills

F5 AWAF administration

Security monitoring

Risk analysis

Firewalls & VPN

Documentation & reporting

Education

Bachelor's degree in Computer Science or Electronics

Tools

Splunk

Nessus

Elastic SIEM

Palo Alto

Forcepoint

Panorama

VPN/Proxy solutions

Citrix

Job description

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 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 with 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 10 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 confirmed 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.
• Location: On-site in Brussels.
• Team: Network & Security team, collaborating with systems, operations, and project teams.

Duration

As soon as possible - 31/12/2026 2 months (full time)

Skills required

• Firewalls et filtrage : routeurs, firewalls stateful packet inspection, firewalls applicatifs (Palo - Level: Expert - Most recent: Any time
• Outils de monitoring et corrélation de logs (Splunk, Nessus, Elastic SIEM) - Level: Expert - Most recent: Any time
• Protocoles et sécurité réseau : TCP/IP, HTTP/HTTPS, SSL, SNMP - Level: Expert - Most recent: Any time
• Sécurisation des réseaux sans fil (WiFi, WEP, WPA, WPA2) et principes de chiffrement (clé publique/p - Level: Expert - Most recent: Any time
• Solutions VPN (remote access et site-to-site) et Web proxy ; solutions terminal-serveur (Citrix) - Level: Expert - Most recent: Any time

Language requirements

Dutch
Level Active knowledge
English
Level Active knowledge
French
Level Active knowledge