OpenWrt Network Configuration

OpenWrt completely replaces the conventional Linux distribution methods of network configuration. The various config files are replaced with the Unified Configuration Interface or ​UCI.

OpenWrt manages its own 'virtual' network interface names in /etc/config/network.

See Also:

• ​OpenWrt Wiki for Wireless
• ​OpenWrt UCI
• OpenWrt Wireless

UCI and config files

You can use the uci command-line utility to get/set configuration or edit the files directly under /system/config (if you know what your doing). Often we will provide uci command-line examples because these can be easily cut-n-pasted into a shell.

UCI configuration can be edited in the files in /etc/config directly or by using uci commands. Often we will provide uci command-line examples because these can be easily cut-n-pasted into a shell.

Network configuration is contained in /etc/config/network.

Example configuration for a single ENET interface:

• looking at /etc/config/network

  root@OpenWrt:/# cat /etc/config/network
  config interface 'loopback'
          option ifname 'lo'
          option proto 'static'
          option ipaddr '127.0.0.1'
          option netmask '255.0.0.0'
  
  config interface 'lan'
          option ifname 'eth0'
          option type 'bridge'
          option proto 'static'
          option ipaddr '192.168.1.1'
          option netmask '255.255.255.0'
          option ip6assign '60'
  
  config interface 'wan6'
          option ifname '@wan'
          option proto 'dhcpv6'
  
  config globals 'globals'
          option ula_prefix 'fda7:b97b:37b2::/48'
  
  

• using UCI:

  root@OpenWrt:/# uci show network
  network.loopback=interface
  network.loopback.ifname=lo
  network.loopback.proto=static
  network.loopback.ipaddr=127.0.0.1
  network.loopback.netmask=255.0.0.0
  network.lan=interface
  network.lan.ifname=eth0
  network.lan.type=bridge
  network.lan.proto=static
  network.lan.ipaddr=192.168.1.1
  network.lan.netmask=255.255.255.0
  network.lan.ip6assign=60
  network.wan6=interface
  network.wan6.ifname=@wan
  network.wan6.proto=dhcpv6
  network.globals=globals
  network.globals.ula_prefix=fda7:b97b:37b2::/48
  

To change the IP address of the lan network which is configured as a bridge containing the eth0 interface using UCI:

uci set network.lan.ipaddr 192.168.1.2
uci commit

You can restart the networking by typing the following command:

/etc/init.d/network restart

Spanning Tree Protocol - STP

The Spanning Tree Protocol (STP) is a network protocol that builds a logical loop-free topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.

By default bridges are configured without STP thus if you connected multiple ports in a bridge to a LAN you would create a bridge loop.

You can enable STP to avoid bridge loops if you do want to connect multiple ports in a bridge to a LAN for redundancy purposes. To do so, edit /etc/config/network and add an option stp 1 to the interface.

For example:

config interface 'lan'
        option ifname 'eth0'
        option force_link '1'
        option type 'bridge'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option stp      1

Verify with the brctl show command:

root@OpenWrt:/# brctl show
bridge name     bridge id               STP enabled     interfaces
br-lan          7fff.00d0127af035       yes             eth0