Networking

Every pipeline is a network program. A Spark job reads from S3 over HTTPS, an Airflow worker opens a TCP connection to PostgreSQL, Kafka clients resolve broker names through DNS, and you reach the production box over SSH through a VPN. When a job “hangs”, the cause is very often a DNS lookup, a firewall rule or a TLS certificate, not your code.

This section teaches the handful of protocols and controls you meet every day, each with a step-by-step animation of what actually goes over the wire.

Protocols

Page What you learn
TCP/IP The layer model, IP addressing and ports, and how TCP’s handshake, acknowledgments and teardown make a reliable byte stream.
UDP Datagrams without a connection, why DNS, video and QUIC use it, and a side-by-side comparison with TCP.
DNS How a name becomes an IP: resolvers, root, TLD and authoritative servers, record types and TTL caching.
HTTP Requests, responses, methods, status codes, headers and caching, plus what changed in HTTP/2 and HTTP/3.
HTTPS TLS 1.3: the one-round-trip handshake, certificates and chains of trust.
SSH Encrypted remote shells, public-key login, known_hosts, and tunnels to private databases.

Concepts

Page What you learn
Firewalls Stateless vs stateful filtering, security groups, default deny and egress rules.
VPN Tunnels and encapsulation, WireGuard and IPsec, site-to-site vs remote access, and zero-trust alternatives.

Learning Resources

Windows Protocols