Preserve Incoming Interface Answers on OpenWrt Router: A Comprehensive Guide

OpenWrt Router: A Comprehensive Guide

OpenWrt is an open-source router firmware that offers a wide range of features and flexibility. This article focuses on configuring an OpenWrt router with three interfaces: br-lan, eth1, and a third interface.

Understanding OpenWrt Interfaces

OpenWrt interfaces are virtual network devices that allow the router to connect to different networks. The three interfaces in this guide are:

• br-lan: This is the LAN network interface with an IP address of 172.16.21.1 and a subnet mask of 255.255.255.0 (or 24-bit subnet mask).
• eth1: This is the WAN network interface with an IP address of 172.16.22.2 and a subnet mask of 255.255.255.252 (or 30-bit subnet mask). This interface is used for Internet access.

Configuring the LAN Interface (br-lan)

To configure the LAN interface, follow these steps:

1. Log in to the OpenWrt web interface.
2. Go to Network > Interfaces.
3. Find the br-lan interface and click Edit.
4. In the General Settings tab, make sure the Protocol is set to DHCP server.
5. In the DHCP Server tab, set the Start and Max number of DHCP leases according to your network requirements.
6. Click Save & Apply to save the changes.

Configuring the WAN Interface (eth1)

To configure the WAN interface, follow these steps:

1. Log in to the OpenWrt web interface.
2. Go to Network > Interfaces.
3. Find the eth1 interface and click Edit.
4. In the General Settings tab, set the Protocol to DHCP client or Static address, depending on your Internet connection type.
5. If using DHCP client, the interface will automatically obtain an IP address from the Internet service provider. If using Static address, enter the appropriate IP address, subnet mask, and gateway provided by your Internet service provider.
6. Click Save & Apply to save the changes.

Configuring the Third Interface

To configure the third interface, follow these steps:

1. Log in to the OpenWrt web interface.
2. Go to Network > Interfaces.
3. Click Add new interface.
4. In the General Settings tab, enter a name for the interface, set the Protocol to None, and choose the correct Physical Settings for the interface.
5. In the Firewall tab, set the Forwarding to LAN and Allow incoming packets to Yes.
6. Click Save & Apply to save the changes.

• OpenWrt interfaces allow the router to connect to different networks.
• The br-lan interface is the LAN network interface with IP address 172.16.21.1 and subnet mask 255.255.255.0.
• The eth1 interface is the WAN network interface with IP address 172.16.22.2 and subnet mask 255.255.255.252.
• The third interface can be configured with a unique name, the None protocol, and LAN forwarding.

References

• OpenWrt Interfaces Guide
• OpenWrt DHCP Guide
• OpenWrt Firewall Guide