If your device has some ports labeled LAN and at least a port labeled WAN and you want it to operate as a router (a connection between two different networks). Depending on actual hardware support, it may be possible to create a WAN port on a device with only LAN ports, see your device’s page for more info about this.
the default IP of the LAN ports of a OpenWrt device is 192.168.1.1, if the addresses of the devices in the network you connect to the WAN port are 192.168.1.X (X=any number), you need to change the IP address of the LAN interfaces your OpenWrt router to 192.168.2.1 (or to something that isn’t 192.168.1.X, anyway), or change the addressing of the other network you are connecting to.
The LAN and WAN ports MUST have at least different subnets for routing to work.

This means:

• OpenWrt will be mostly in its default factory configuration
  • firewall on
  • DHCP is on
• The following steps are optional:
  • you can customize the router address and the address of the subnet that OpenWrt manages, but you don’t have to (you preferably want to do this, if the addresses 192.168.1.* are already in use on the WAN side)
  • you can change the WAN side IP address to no longer obtain a dynamic address: if your ISP wants you to set a fixed address then set it to a fixed address instead
• If you are confused now or don’t know, simply start by leaving both config parts in its default configuration. If you experience problems with these defaults, then adapt them accordingly later.

Luci instructions:

1. Click on Network → Interfaces, then click on the Edit button of the LAN Network.
2. In General Setup tab, in IPv4 address write the static address of this device, if your router’s address is 192.168.1.1 (most common) you can usually choose any address from 192.168.1.2 to 192.168.1.250. Once you have chosen and written the IP address, write it down in the same sticker with the user/password above, it will be used to connect to your device in the future.
3. By default the WAN interface/port is set as DHCP client, this will allow it to work with networks where there is another router giving addresses without further configuration. If you need to set static address please see the instructions for Client device, and change the WAN interface settings accordingly.

Command line instructions:

1. type uci set network.lan.ipaddr='new-ip-address‘ (“new-ip-address” is the new IP address you want for the LEDE device in your network) and press Return,
2. if needed, type uci set network.wan.proto='static‘ to switch to static protocol on WAN interface, then change wan settings by using the same procedure detailed for Client device, settings for wan interface are network.wan.ipaddr, network.wan.gateway, network.wan.dns, and so on, so change the commands accordingly.
3. You might want to basic OpenWrt documentation too, as these setups are usually very specific to your own network setup and it makes no sense to try to cover all possible cases here.
4. type uci commit && service network restart and press Return
5. then connect again to your device at its new IP address and continue