Network Security Engineer
Confirmed on the employer's own hiring board on Oct 27, 2026. First seen by Alion on Sep 2, 2026. Cloudflare scores B on the Alion truth index.
About Us
At Cloudflare, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies. Cloudflare protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by Cloudflare all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. Cloudflare was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company.
At Cloudflare, we’re not looking for people who wait for a polished roadmap; we’re looking for the builders who see the cracks in the Internet that everyone else has simply learned to live with. We value candidates who have the instinct to spot a "normalized" problem and the AI-native curiosity to create a solution using the latest tools. Our culture is built on iteration, leveraging AI to ship faster today to make it better tomorrow, while ensuring that every improvement, no matter how small, is shared across the team to lift everyone up. If you’re the type of person who values curiosity over bureaucracy, and that AI is a partner in solving tough problems to keep the Internet moving forward, you’ll fit right in.
Available Locations: Lisbon, Portugal
About the role
Do you love solving complex technical issues and interacting with people? Are you passionate about providing premium-level support to customers and are a standout colleague? Cloudflare is seeking an experienced Network Security Engineer to join our team and support our largest and most technically sophisticated customers in resolving technical problems, threats or attacks on their infrastructure at OSI Layers 3, 4, and 7. This will span the range of Cloudflare products from Magic Transit Infrastructure Protection, Argo Smart Routing, DDoS mitigation and Network Firewall, to using the Web Application firewall (WAF), Spectrum and Rate Limiting to help customers.
Responsibilities
- Communicate with customers via chat, email, and phone
- Compare traffic signatures and attributes including IP addresses, cookie variations, HTTP headers, and JavaScript footprints to determine what is good traffic and what is malicious
- DDoS mitigation for OSI layers 3,4, & 7: advise customers on how to filter malicious traffic using Cloudflare tools like Magic Transit, Network Firewall, WAF, IP reputation lists, packet inspection, blocklisting, allowlisting, and rate limiting
- Work with Engineering and Operations teams to mitigate attacks, suggest steps to mitigate, and apply the appropriate mitigation, when applicable
- Work with Engineering and Product teams to improve the products and tools
Desirable Skills, Knowledge, and Experience:
- Self-driven and capable of learning new technologies / systems / features with little guidance
- Fundamental understanding how the Internet works (OSI Model)
- Advanced understanding of modern internet protocols like TCP and UDP
- Computer Networking fundamentals, experience with iptables and looking glass
- Experience troubleshooting network connectivity issues, BGP routing, and GRE tunnels
- Packet capture analysis
- Experience in command line and tools, including curl, dig, traceroute, openssl, git
- Experience troubleshooting DNS, SSL / TLS, HTTP
- Experience in a web development and / or hosting environment such as installing and configuring web servers like Apache, Nginx, Caddy and IIS
- Experience writing scripts in Bash, Python, JavaScript or other scripting language
- Experience in working as part of a team in a customer-facing role
Bonus Points
- You are fluent in German, Japanese, French, Spanish, Portuguese, or Mandarin
- You have worked with PostgreSQL, MySQL, MS SQL, and other database servers
- You are familiar with Cloudflare and are actively using our platform
Compensation
Compensation may be adjusted depending on work location.
- For Lisbon based hires: Estimated annual salary of €38,000-52,000.
Equity
This role is eligible to participate in Cloudflare’s equity plan.
What Makes Cloudflare Special?
We’re not just a highly ambitious, large-scale technology company. We’re a highly ambitious, large-scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.
Project Galileo: Since 2014, we've equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by Cloudflare’s enterprise customers--at no cost.
Athenian Project: In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection and reliability for free, so that their constituents have access to election information and voter registration. Since the project, we've provided services to more than 425 local government election websites in 33 states.
1.1.1.1: We released1.1.1.1 to help fix the foundation of the Internet by building a faster, more secure and privacy-centric public DNS resolver. This is available publicly for everyone to use - it is the first consumer-focused service Cloudflare has ever released. Here’s the deal - we don’t store client IP addresses never, ever. We will continue to abide by our privacy commitment and ensure that no user data is sold to advertisers or used to target consumers.
Sound like something you’d like to be a part of? We’d love to hear from you!
Please note that applicants who progress to the offer stage of the interview process may be asked to attend an in-person interview within one of the Cloudflare Offices or Cloudflare Hubs. More details about this will be available at that stage of the interview process.
This position may require access to information protected under U.S. export control laws, including the U.S. Export Administration Regulations. Please note that any offer of employment may be conditioned on your authorization to receive software or technology controlled under these U.S. export laws without sponsorship for an export license.
Cloudflare is proud to be an equal opportunity employer. We are committed to providing equal employment opportunity for all people and place great value in both diversity and inclusiveness. All qualified applicants will be considered for employment without regard to their, or any other person's, perceived or actualrace, color, religion, sex, gender, gender identity, gender expression, sexual orientation, national origin, ancestry, citizenship, age, physical or mental disability, medical condition, family care status, or any other basis protected by law. We are an AA/Veterans/Disabled Employer.
Cloudflare provides reasonable accommodations to qualified individuals with disabilities. Please tell us if you require a reasonable accommodation to apply for a job. Examples of reasonable accommodations include, but are not limited to, changing the application process, providing documents in an alternate format, using a sign language interpreter, or using specialized equipment. If you require a reasonable accommodation to apply for a job, please contact us via e-mail at [email protected] via mail at 101 Townsend St. San Francisco, CA 94107.