---
title: 'Networking: From an HTTPS Request to Independent Troubleshooting'
url: https://doc.liz6.com/en/networking/00-learning-path
locale: en
area: networking
tags:
- Networking
date: 2026-09-12
modified: 2026-09-12
description: For readers who can use the terminal and know how browsers access URLs; no need to memorize the protocol stack beforehand. Track an HTTPS request using a client and test service you can manage, saving the address, time, and actual output at each step.
---

# Networking: From an HTTPS Request to Independent Troubleshooting

For readers who can use the terminal and know how browsers access URLs; no need to memorize the protocol stack beforehand. Track an HTTPS request using a client and test service you can manage, saving the address, time, and actual output at each step.

## What you will build

Explain what problems are solved by names, addresses, routing, connections, encryption, and application requests, and use controlled experiments to locate the layer where "the webpage cannot be opened."

## Required reading and checkpoints

1. [Ethernet and MAC](01-l2-data-link/01-ethernet-and-mac.md) → [ARP and NDP](01-l2-data-link/02-arp-and-ndp.md) → [IPv4 Protocol](02-l3-network-layer/01-ipv4-protocol.md).

   Draw the path from the client to the gateway, and list the local address, subnet, default route, and neighbors. Self-check: What are the destination IP and next-hop MAC when accessing within the same subnet versus across subnets?

2. [DNS Protocol and Resolution](04-DNS/01-dns-protocol-and-resolution.md) → [TCP](03-l4-transport-layer/01-tcp.md) → [TLS 1.3 Handshake](05-tls-and-pki/02-tls-1-3-handshake.md) → [HTTP/1.1](06-HTTP/01-HTTP1.1.md).

   Divide a request into resolution, connection, TLS, and HTTP. Self-check: Successful resolution does not prove port reachability; port reachability does not prove certificate or application correctness. Be able to explain the relationship between domain names, SNI, and certificate hostname verification.

3. [tcpdump and Wireshark](13-network-diagnostics/01-tcpdump-and-wireshark.md) → [Network Troubleshooting Methodology](13-network-diagnostics/02-network-troubleshooting-methodology.md).

   Perform controlled variable comparisons using the same target but different paths. Self-check: Change only one condition among resolution results, proxy, or client, and clearly write down the expected observations versus actual observations, avoiding the mistake of treating a single ping failure as a machine downtime.

## Optional branches

Complete the main track first, then look at [IPv6](02-l3-network-layer/02-ipv6-protocol.md), [HTTP/2](06-HTTP/02-HTTP2.md), [HTTP/3](06-HTTP/03-HTTP3.md), and QUIC. For home gateway arrangements, connect [Transparent Proxy and TUN](07-proxy-protocol/02-transparent-proxy-and-tun.md); for remote access, connect [WireGuard](08-vpn-and-tunnels/01-wireguard-protocol.md). WebRTC, email, OAuth, and protocol design are optional readings based on projects.

## Completion task

Submit a layered timeline of a successful request, and a troubleshooting record for a manually induced failure (e.g., testing domain resolution pointing to an incorrect address); explain which outputs overturned your initial hypothesis. When latency changes with load, refer to [Queueing Theory](../theory/03-queueing-theory/index.md). For actual home network issues, check the [Network Recovery Manual](../homelab/network-recovery.md), where addresses are specific to the environment configuration.

Skipping long proofs and implementation details is allowed during the first read, but you must complete the phase self-checks first. When you find yourself "knowing the terms but unable to explain the results," return to the current example, change one condition, and then proceed to the next section; there is no need to read the entire table of contents beforehand.