# Networking

> How the internet really works, and how to design networks that hold up - from your home router to the enterprise.

9 guides.

- [How the Internet Actually Works](https://themissingmanual.dev/guides/how-the-internet-works) _(beginner)_ - The absolute basics of networking: what happens when you open a web page - how your request travels to a server and back, how machines find each other by address and name, and how they agree on a shared language.
- [IP Addresses, DNS & Ports, Explained](https://themissingmanual.dev/guides/ip-dns-and-ports) _(beginner)_ - The address book of the internet: what an IP address really is, how DNS turns names like example.com into numbers, and how ports let one machine run many services at once.
- [HTTP, Explained - the language the web speaks](https://themissingmanual.dev/guides/http-explained) _(beginner)_ - What HTTP actually is: every time you load a page, your browser sends a request and a server sends a response. This guide makes that conversation - methods, status codes, headers, cookies, and the S in HTTPS - finally make sense.
- [Your Home Network, Explained](https://themissingmanual.dev/guides/your-home-network) _(beginner)_ - What that box on your shelf actually is - the modem connects you to your ISP, the router shares that connection with all your devices, NAT lets them share one public IP, and a few settings keep the whole thing safe.
- [The TCP/IP Model Without the Acronym Soup](https://themissingmanual.dev/guides/tcp-ip-model) _(intermediate)_ - The layered model, finally intuitive: each layer does one job and trusts the layer below, like nesting envelopes - Link, Internet, Transport, Application, plus TCP vs UDP and a packet's round trip.
- [Troubleshooting Networks](https://themissingmanual.dev/guides/troubleshooting-networks) _(intermediate)_ - A calm, methodical way to debug 'the internet is broken' - work up the layers (link, IP, gateway, DNS, destination), then use ping, traceroute, dig, and a packet capture to read exactly where the conversation died.
- [Designing an Enterprise Network](https://themissingmanual.dev/guides/designing-an-enterprise-network) _(advanced)_ - How to grow from a single home router into a network that holds up: segmentation to limit blast radius, scaling and redundancy to survive load and failure, and a security edge - firewalls, DMZ, VPN, zero-trust - that keeps the inside safe.
- [What a VPN Actually Does](https://themissingmanual.dev/guides/what-a-vpn-does) _(beginner)_ - What a VPN really routes and hides, and what it does not: the encrypted-tunnel model, who can see what, and when a VPN is mostly theater.
- [Email, Demystified (SPF, DKIM, DMARC)](https://themissingmanual.dev/guides/email-demystified) _(intermediate)_ - How email really travels and why yours lands in spam: SMTP, plus the three DNS records that prove a message is truly from your domain.