Whichcast

What this IPv4 addressing question tests

This is a foundational networking question that tests whether you understand IPv4 address space allocation and the purpose of reserved ranges. It is the kind of question that appears in systems and infrastructure interviews, particularly at firms building low-latency trading infrastructure or network-heavy applications where routing and packet delivery semantics matter.

To answer well, you need to recall not just the numeric range, but the functional purpose of a specific IPv4 class and how it differs from unicast addressing. The question rewards precision: knowing the exact use case, the scale of the address space, and why this design choice was made. It often leads to follow-up questions about how these packets are routed, what protocols rely on them, and how they interact with network topology.

• IPv4 address classes and their ranges
• Multicast vs. unicast semantics
• Network scope and TTL (Time To Live)
• Practical deployment in distributed systems