Network Fundamentals Visualized
This topic explains DNS, TCP, TLS, HTTP/2, HTTP/3, proxies, cache revalidation, and CDN behavior through observable request paths. The goal is not to memorize protocol names. The goal is to understand what happens between a browser action and a response: name resolution, routing, connection setup, encryption, forwarding, caching, and application delivery.
Network issues are often reported as vague symptoms: a site is slow only sometimes, works from one location but not another, or changes behavior after a cache purge. To debug those cases, the layers need to be separated. The articles in this hub use headers, status codes, RTTs, cache states, packet-level ideas, and small scripts to make that separation visible.
Recommended Order
Start with DNS TTL caching and CIDR/MTU calculations to build the addressing and routing base. Then move through TCP reliability, TLS 1.3 handshakes, and HTTP CONNECT tunnels to understand connection state and encryption boundaries. After that, the reverse proxy, cache revalidation, HTTP/3, and CDN waterfall articles connect the fundamentals to real website operations.
When following the examples, keep notes about request headers, response headers, status codes, certificate details, cache hits, and timing phases. The same page load can involve the browser cache, Cloudflare, Nginx, an upstream application, and a DNS resolver. Seeing which layer made a decision is the core skill.
Responsible Use
All experiments are intended for local labs, owned infrastructure, or public resources that allow this kind of testing. Do not use the proxy, TLS, traffic analysis, or caching examples against systems you are not authorized to test. Real networks also vary by ISP, browser version, firewall policy, CDN configuration, and server settings, so article output should be treated as a reproducible learning reference rather than a universal guarantee.
Topic hub
Network Fundamentals Visualized
A reproducible route through DNS, TCP, TLS, HTTP/3, proxy tunnels, load balancing, and shared caching.
For engineers investigating protocol latency, HTTPS proxy boundaries, SOCKS DNS, reverse-proxy queues, and cache correctness.
Editorial notes
Why these articles belong in one route
Networking articles can easily become configuration snippets, so this hub breaks each protocol layer into reproducible observations: DNS cache hits, CIDR matching, TCP congestion windows, TLS key phases, HTTP cache revalidation, and proxy boundaries.
Each article answers an engineering question: where latency comes from, which fields affect routing or caching, what a proxy can see, and which optimization simply moves the bottleneck elsewhere.
The labs use local models or deterministic scripts by default and do not provide an external proxy service for bypassing controls. The focus is protocol behavior, security boundaries, and operational observability.
What you will build
You will calculate protocol and proxy boundaries, run Python/C labs, inspect figures and animation, and separate performance gains from trust risks.
Recommended reading order
Start with concepts, then move into runnable projects
DNS Resolution Explained: Build a TTL Cache and Packet Parser in Python
A runnable DNS guide covering resolution paths, response headers, TTL cache latency, and deterministic Python/C experiments.
CIDR, Longest Prefix Match, and MTU: Calculate IP Routing Step by Step
Calculate CIDR ranges, longest-prefix route choice, and MTU/MSS payload segmentation with runnable Python and C examples.
TCP Reliability and Congestion Window: A Runnable Sequence Number Experiment
Track TCP sequence numbers, cumulative ACKs, loss, retransmission, and congestion-window changes with safe local experiments.
HTTPS and TLS 1.3 Handshake: Keys, Certificates, and RTT in Practice
Understand TLS 1.3 message flights, certificate authentication, ephemeral key agreement, and handshake latency with a safe teaching model.
HTTP/2, HTTP/3, and CDN Caching: Read Page Speed from a Waterfall
A deterministic browser-waterfall model for HTTP/2, HTTP/3, QUIC streams, and CDN cache hits or misses.
Forward Proxy vs Reverse Proxy: Connection Paths, Trust Boundaries, and Latency
A reproducible guide to forward proxies, reverse proxies, tunnels, TLS boundaries, and latency segments.
HTTP CONNECT and HTTPS Proxy Tunnels: TLS Boundaries and Handshake Latency
An RFC-based explanation of CONNECT tunnels, encrypted HTTPS payloads, and modeled first-request latency.
SOCKS5 Proxy Explained: Protocol Bytes, DNS Resolution Boundaries, and Leakage Risk
Decode safe SOCKS5 CONNECT bytes and compare local-DNS and proxy-side hostname resolution boundaries.
Reverse Proxy Load Balancing: Queues, Health Checks, and a Reproducible Scheduler
Compare round robin and load-aware queue selection while reasoning about health checks and retry boundaries.
Proxy Cache Revalidation: Cache-Control, ETag, and Observable Correctness
Use an RFC 9111 shared-cache model to calculate MISS, HIT, and 304 revalidation latency and correctness boundaries.
Resources and distribution assets
Code, data, diagrams, and share assets in one place
Network Fundamentals / GUIDE
Network Fundamentals Lab README
Setup, no-privilege safety boundary, ten Python experiments, and three C examples.
Network Fundamentals / ARCHIVE
Network fundamentals full lab bundle
Bundles Python/C source, fixed scenarios, ten result CSVs, and protocol/proxy figures.
Network Fundamentals / DATASET
DNS TTL results CSV
HIT/MISS state, expiry, and latency for four fixed lookups.
Network Fundamentals / DATASET
CIDR and MTU results CSV
Longest-prefix route and 3600-byte payload segmentation results.
Network Fundamentals / DATASET
TCP cwnd events CSV
Per-round ACK, window, and deterministic retransmission events.
Network Fundamentals / DATASET
TLS 1.3 flight results CSV
Message direction, timing, and teaching shared value in a fixed RTT model.
Network Fundamentals / DATASET
HTTP/CDN waterfall results CSV
Phase timing for HTTP/2 and HTTP/3 in cold and warm cache models.
Network Fundamentals / DATASET
Proxy path latency results CSV
Phase timing for direct access, forward-proxy tunneling, and reverse-proxy cache paths.
Network Fundamentals / DATASET
CONNECT/TLS timeline CSV
Records CONNECT authority, tunnel establishment, and the encrypted HTTPS-request boundary.
Network Fundamentals / DATASET
SOCKS5 DNS boundary CSV
Stores ATYP, destination bytes, request length, and modeled local DNS counts.
Network Fundamentals / DATASET
Proxy load-balancing queue CSV
Compares backend selection and queue waiting for round robin and least queue.
Network Fundamentals / DATASET
Proxy cache revalidation CSV
Records MISS, HIT, 304 revalidation, object age, and response latency.
Network Fundamentals / TOOL
Network request path visualizer
Adjust TTL, prefixes, loss, handshake RTT, and cache paths in the browser.
Network Fundamentals / SOCIAL
Network fundamentals topic share card
A 1200x630 SVG card for the DNS, TLS, HTTP/3, proxy tunnel, and caching topic hub.
FAQ
Direct answers to common search questions
Do the labs require packet capture or administrator rights?
No. The labs use fixed scenarios and localhost; live commands are optional observation only.
Do these models represent actual network performance directly?
No. They isolate protocol factors; production decisions still require real-user metrics, cache headers, and network observation.
Do the proxy labs create a proxy suitable for bypassing access controls?
No. The new labs encode protocol bytes or execute deterministic local models; they configure no external proxy and forward no real target traffic.