Computer Networking for Developers: IP, TCP, DNS, HTTP and TLS

Contents

Every lesson has the same steps: what it is, how it works, a real example, common mistakes, then interview questions with answers you can say out loud.

1. Lesson 00How the Internet Works: Layers, Packets and AddressesThe layer models, what a packet is, MAC, IP and ports, and following one request from your laptop to a server.13 min
2. Lesson 01IP Addresses, Subnets, NAT and RoutingIPv4 and IPv6, CIDR notation worked by hand, private ranges, NAT, routing tables and how a packet finds its way.14 min
3. Lesson 02TCP and UDP: Connections, Reliability and CongestionThe three-way handshake, sequence numbers, retransmission, flow and congestion control, UDP, and when each is used. Captured with real packet tools.16 min
4. Lesson 03DNS: How Names Become AddressesResolvers, root and authoritative servers, record types, TTL and caching, and debugging DNS with dig.14 min
5. Lesson 04HTTP/1.1, HTTP/2 and HTTP/3Requests and responses on the wire, keep-alive, head-of-line blocking, multiplexing, QUIC, and what changes for you as a developer.15 min
6. Lesson 05TLS and Certificates: How HTTPS Really WorksThe handshake in plain words, certificates and chains, Let's Encrypt, mTLS, and the errors you will meet.15 min
7. Lesson 06Load Balancers, Proxies, CDNs and FirewallsLayer 4 and layer 7 balancing, reverse and forward proxies, CDNs, caching at the edge, and firewalls and security groups.14 min
8. Lesson 07WebSockets, Server-Sent Events and Real-Time NetworkingPolling versus long polling, WebSockets, SSE, scaling real-time connections, and a working example of each.14 min
9. Lesson 08Debugging Network Problems and Networking Interview Questionscurl, dig, ss, tcpdump and Wireshark basics, a troubleshooting checklist, and interview questions with model answers.16 min