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Salary: EUR 38,000 - 52,000 / annual
Cloudflare is seeking an experienced Network Security Engineer to join their team in Lisbon and support enterprise customers in resolving technical problems, threats, and attacks on their infrastructure across OSI Layers 3, 4, and 7. You will work with Cloudflare's suite of security products including Magic Transit Infrastructure Protection, Argo Smart Routing, DDoS mitigation, Network Firewall, Web Application Firewall (WAF), Spectrum, and Rate Limiting.
Key responsibilities include communicating with customers via chat, email, and phone to diagnose and resolve security issues. You'll analyze traffic signatures and attributes—IP addresses, cookie variations, HTTP headers, and JavaScript footprints—to distinguish legitimate traffic from malicious activity. You'll advise customers on DDoS mitigation strategies using Cloudflare tools, work cross-functionally with Engineering and Operations teams to execute mitigations, and collaborate with Product teams to improve tools and features.
Required skills include a fundamental understanding of how the Internet works (OSI Model), advanced knowledge of TCP/UDP protocols, computer networking fundamentals, and experience troubleshooting network connectivity, BGP routing, and GRE tunnels. You should be comfortable with packet capture analysis, command-line tools (curl, dig, traceroute, openssl, git), and troubleshooting DNS, SSL/TLS, and HTTP. Experience with web servers (Apache, Nginx, Caddy, IIS) and scripting languages (Bash, Python, JavaScript) is expected. You'll thrive in a customer-facing, team-oriented environment and be self-driven to learn new technologies with minimal guidance.
Bonus qualifications include fluency in German, Japanese, French, Spanish, Portuguese, or Mandarin; experience with PostgreSQL, MySQL, or MS SQL; and familiarity with Cloudflare's platform.
