Skip to main content

Network basics before routerd

You do not need to know every networking term before trying routerd. This page gives you the small mental model needed for the first tutorial.

The picture to keep in mind​

Internet / school / provider network
                |
               WAN
                |
          [ routerd host ]
                |
               LAN
                |
       PCs, phones, game consoles
  • WAN is the side that faces a provider, school, or upstream router.
  • LAN is the side you control: a room, home, class, or test network.
  • A router moves packets between those two sides. It is not the same thing as a Wi-Fi access point or an Ethernet switch.

Six useful words​

WordPlain-language meaning
IP addressA network address, like a delivery address for a device.
GatewayThe device a computer sends traffic to when the destination is outside its own LAN. In a small network this is usually the router.
DHCPA service that automatically gives a device an IP address, gateway, and often DNS server.
DNSA phone book that turns a name such as example.com into an IP address.
NATA way for many LAN devices to share one IPv4 connection to the outside.
/24A short way to say that addresses such as 192.168.10.1 through 192.168.10.254 belong to one small IPv4 LAN.

routerd writes these choices as YAML. A Router file is a box containing a list of resources. Each resource has a kind (what it is), a metadata.name (a label you choose), and a spec (the details).

apiVersion: routerd.net/v1alpha1
kind: Router
metadata:
  name: my-lab-router
spec:
  resources:
    # Resources such as Interface, DHCPv4Server, and NAT44Rule go here.

You do not need to memorize the resource names. The tutorials introduce one job at a time and link to the reference when you need it.

Start safely​

For a first experiment, use an isolated Ubuntu Server VM or a spare computer. Keep a Proxmox/VM console, serial console, or a separate management NIC. Do not start by changing the only router that carries your home, school, or work connection.

routerd validate and routerd apply --once --dry-run are for checking a file without committing network changes. routerd apply --once and routerd serve can change the host network. Only run those live commands from a console or an independent management path.

Firewall boundary

routerd is pre-release software. Its firewall resources are groundwork, not a security certification. Do not expose an Internet-facing router or rely on a single example as your only security boundary.

Next steps​

  1. Install routerd on an isolated Ubuntu Server VM.
  2. Run the safe first check without changing its network.
  3. Build the first IPv4 lab router only after you have a console path.