IP Addressing

This guide covers how to configure static IP addresses on OpenWrt routers and create an IP addressing plan for your community network.

This guide implements the concept introduced in Chapter 2 — IP Addressing.

What You'll Learn

• How to change a router's IP address in OpenWrt LuCI
• When to use static IPs vs DHCP
• How to set up a gateway for traffic routing
• How to document your IP plan for troubleshooting

Prerequisites

• At least one router running OpenWrt with LuCI web interface
• Ethernet cable for initial configuration
• Basic understanding of IP addresses (e.g., 192.168.1.1)

Step-by-Step Implementation

1. Plan your network IP range

Before changing any settings, decide what IP range your network will use.

1. If you don't expect more than 255 devices, a /24 network (e.g., 192.168.70.0/24) is sufficient.
2. Choose a range that doesn't conflict with common defaults. Avoid 192.168.1.x and 192.168.0.x since most routers use these out of the box.
3. Pick a consistent scheme. For example, 192.168.70.x for your entire deployment.

2. Connect to the router

1. Connect your computer to the router using an Ethernet cable.
2. Open a web browser and navigate to the router's current IP address (usually 192.168.1.1).
3. Log in with your OpenWrt credentials.

3. Navigate to the LAN interface settings

1. In LuCI, go to Network → Interfaces → LAN and click Edit.

4. Configure the static IP address

1. In the IPv4 address field, enter the new IP for this router (e.g., 192.168.70.1).
2. Set the IPv4 netmask to 255.255.255.0 (for a /24 network).
3. If this router needs to route traffic through another device (e.g., a main gateway router), enter that device's IP in the IPv4 gateway field.
4. Click Save & Apply.

5. Repeat for additional routers

1. Connect to each additional router.
2. Assign it a unique IP within your chosen range (e.g., 192.168.70.2, 192.168.70.3, etc.).
3. Set the gateway to point to your main internet-connected router if needed.

6. Document your IP addressing plan

Create a simple document or spreadsheet that tracks:

• Device name — what the device is (e.g., "Office Router", "Classroom AP")
• IP address — the assigned static IP
• Location — where the device is physically located
• MAC address (optional) — useful for DHCP reservations

Summary

References

• OpenWrt Documentation — Network Basics — https://openwrt.org/docs/guide-user/base-system/basic-networking
• OpenWrt Documentation — Static IP Configuration — https://openwrt.org/docs/guide-user/network/ipv4.configuration

Revision History