Computer Networking for Developers and DevOps
Understand computer networking the practical way for devs/DevOps: the layered model, IP and subnets, TCP/UDP, DNS, HTTP/HTTPS, TLS, NAT, firewalls, load balancers, and troubleshooting. Goes from 'what happens when you open a web page' to tracing a request end to end.
How Networking Works: What Happens When You Open a Web Page
Series kickoff: trace a request's journey when you type a web address — from DNS resolution, the TCP handshake, TLS encryption, to HTTP and the response. Each leg is its own article ahead, assembled into a complete picture of networking.
The Layered Model: OSI and TCP/IP
The most important mental framework of the whole series: networking is designed as layers, each handling one job and relying on the layer below. Understand the 7 OSI layers, the 4 TCP/IP layers, and how data is encapsulated through each layer.
IP Addresses and Subnets
Every device on a network has an IP address. This article explains IPv4 structure, the network part and host part, the subnet mask and CIDR notation (/24), private (RFC 1918) vs public addresses, and why IPv6 exists.
The Link Layer: MAC, ARP and Switches
Within a local network (LAN), machines find and send data to each other by MAC address, not IP. This article explains MAC, why you need both MAC and IP, the ARP protocol that links the two addresses, and how a switch works.
Routing: Routers, Gateways and the Routing Table
How does a packet travel from your machine to a server on the other side of the world? This article explains routers, the default gateway, the routing table, and how a packet hops across each leg (hop) — observed for real with traceroute.
NAT and Private/Public IPs
Why does a whole household share one public IP out to the Internet? This article explains NAT — the mechanism by which a router translates private IPs into a public IP, tracks them by port, and why incoming connections from outside need port forwarding.
TCP and UDP: Ports and Connections
A deep dive into the transport layer: how a port identifies which service, how TCP's three-way handshake creates a reliable connection, the connection states, and UDP when you need speed over certainty. Observed for real with netstat and nc.
DNS: Resolving Domain Names
A deep dive into DNS — the system that translates domain names into IPs. Understand the root/TLD/authoritative hierarchy, recursive resolvers, the step-by-step resolution flow, record types (A, CNAME, MX, NS, TXT), and the role of TTL/cache. Observed live with dig.
HTTP and HTTPS
The language of the web: the request/response structure, methods (GET/POST...), status code groups (2xx/3xx/4xx/5xx), headers, and the evolution from HTTP/1.1 → 2 → 3. HTTPS is HTTP plus encryption. Observed live with curl -v.
TLS/SSL: Encryption and Certificates
A deep dive into the 'S' in HTTPS: how TLS handshakes and encrypts, what a certificate contains, and how the chain of trust from a server certificate up to a root CA lets the browser trust a website. Observed live with openssl.
Firewalls and Network Security
Controlling who can connect to which port: a firewall filters traffic by IP, port, and direction. Understand the default-deny principle, stateful firewalls, iptables/nftables on Linux, ufw, and cloud security groups.
Load Balancers and Reverse Proxies
One server can't carry all the traffic. A load balancer spreads load across many servers; a reverse proxy sits in front to shield and route. Understand L4 vs L7, load-balancing algorithms, health checks, and TLS termination.