interviewed for a software engineer role at Fortinet and wanted to share my experience to help others preparing for the process.

The interview process started with an online application, followed by a recruiter screening call. The recruiter was friendly and provided a clear overview of the role, team, and expectations.

The next step was a technical assessment, which consisted of algorithm and data structure problems. The difficulty was moderate – similar to what you’d find on LeetCode medium level.

After passing the assessment, I was invited to a series of technical interviews with engineers from the team. These rounds focused on system design, problem-solving, and coding in C++ (your primary language may vary).

Some questions were very specific to networking concepts, so it helps to brush up on TCP/IP, firewalls, and general computer networking knowledge.

The interviewers were professional, though some were a bit reserved. One of the interviewers asked questions that seemed pulled directly from textbook definitions rather than focusing on real-world application, which made the conversation slightly rigid. However, they were open to follow-up questions and explanations.

The final round was a managerial interview where we discussed team dynamics, career goals, and how I would fit into their culture. It was more relaxed and gave a good sense of the company’s work environment.

You're given a stream of network packets. Each packet has a source IP, destination IP, and a timestamp.

Design a system to detect if a particular IP address is making more than 1000 requests per minute (i.e., rate limiting).

How would you approach this problem?