TCP Checksum Coverage

Understanding TCP header checksum coverage in networking interviews

This is a straightforward easy conceptual question about the TCP/IP stack that tests whether you understand what data the checksum actually protects. It's the kind of foundational question that firms ask to ensure you can reason clearly about protocol design and data integrity.

To answer it correctly, you need to identify which parts of a TCP packet are included in the checksum calculation and which are not. The question probes your grasp of how TCP ensures reliability: what gets verified, what scope of the packet is covered, and why that scope was chosen. Interviewers use this to gauge whether you can read and interpret protocol specifications accurately.

• TCP header structure and fields
• Payload vs. metadata protection
• Pseudoheader and its role in checksum computation
• Contrast with other transport-layer checksums