How the facts in this guide were checked
Historical claims, protocol details, and specific numbers were verified against primary sources. Specifically confirmed:
- RFC 9293 (Transmission Control Protocol) was published August 2022 and obsoletes RFC 793 (1981) — a 41-year gap.
- Linux TIME_WAIT is hardcoded at 60 seconds (
TCP_TIMEWAIT_LEN, defined as 2 × MSL) and is not controlled bynet.ipv4.tcp_fin_timeout, which governs theFIN_WAIT_2state instead. (This is widely misreported online; Chapter 23 states it correctly.) - RFC 1918 private ranges:
10.0.0.0/8,172.16.0.0/12,192.168.0.0/16. - Standard Ethernet MTU 1500, giving MSS 1460 after 20-byte IP and 20-byte TCP headers.
- All subnetting answers in Appendix C were computed and independently verified.
- The 1986 NSFNET congestion collapse (throughput falling from 32 kbit/s to 40 bit/s) and Van Jacobson's 1988 congestion-control response.
What changes and should be re-checked before you rely on it: command syntax and flags across OS versions, specific tool availability, cloud provider behaviour, and anything about "current" adoption levels of IPv6 or HTTP/3. The protocol fundamentals in Parts 1–7 are stable and have been for decades.