Practical Networking: IPs, Subnets, and Routing Demystified

Networking can feel intimidating, but the core ideas are simple: IP addresses identify devices, subnets group addresses for efficient routing, and routing moves packets from one network to another. This short guide uses clear examples you can reuse at home or in a small office.

What is an IP address?

An IP address acts like a postal address for a device on a network. It can be IPv4, written as four numbers separated by dots, or IPv6, a longer hex format. In practice, you see both kinds, but most home networks still rely on IPv4 for everyday tasks.

  • IPv4 private addresses, such as 192.168.1.10, stay inside your local network and are not directly reachable from the internet.
  • Public IPv4 addresses, like 203.0.113.42, are reachable on the wider web.
  • IPv6 examples, such as 2001:db8:85a3::8a2e:370:7334, are common as more devices join networks.

Subnets and CIDR notation

An IP address alone doesn’t define a network. A subnet mask or CIDR block tells you how large the local network is. For example, 192.168.1.0/24 means all addresses from 192.168.1.0 to 192.168.1.255 belong to the same network. The /24 block holds 256 addresses, with several reserved for network services.

  • 192.168.1.0/24 contains 256 addresses, and 192.168.1.1 is a typical gateway.
  • Smaller blocks, like /25 or /26, carve out half or quarter sizes of a network.

CIDR notation makes planning easier, because you can see how many devices fit in a network and how routes should be organized.

Routing in everyday networks

Routing is the job of moving a packet from your device to its destination. Your router is the gateway for your LAN and it knows how to reach the internet. A routing table lists paths: direct connections and next-hop addresses. When you reach for a web page, your device forwards the request to the gateway, which passes it along until the response returns along the same path.

Static routing is fixed, while dynamic routing adapts to changes in the network. For most homes, the router handles everything automatically, which keeps things simple and reliable.

A simple home network example

Picture a small setup: a laptop at 192.168.1.20, a printer at 192.168.1.50, and the router at 192.168.1.1. When you visit a site, the laptop sends the request to 192.168.1.1. The router forwards it to your ISP, out to the internet, and the data returns the same way. Devices behind the router share the same gateway, keeping traffic organized and secure.

Practical tips

  • Plan your private addressing in one block, such as 192.168.1.0/24, to avoid overlaps.
  • Use the router as the default gateway and let DHCP assign end devices are simple, predictable addresses.
  • Reserve a few addresses for printers, servers, or network gear to prevent conflicts.
  • Document changes to the network map so you can troubleshoot quickly later.

Key Takeaways

  • An IP address names devices; CIDR notation defines network size.
  • Subnets group addresses to make routing easier and cleaner.
  • The gateway and routing table guide packets from your devices to the internet.