WAN as LAN (Legacy Firmware)

Introduction

To find out how to set up your router's WAN port to function as LAN on RUTX devices, follow this guide.

WAN ports on RUT2xx, RUT850 and RUT9xx routers can also function as LAN ports. However, this is not the default setting and must be set manually by following the steps described below.

RUT2xx and RUT9xx

Steps to follow

1. Login to the router's WebUI and navigate to the LAN section (Network → LAN):
2. Under the Configuration section, click "Advanced Settings" and place a check mark next to the "Use WAN port as LAN" field and don't forget to save your settings:

RUT850

RUT850 has the possibility to act as a WLAN access point and WLAN station same time. The WLAN station interface usually is dedicated to be one of the WAN interfaces. But it can also be used as LAN interface and allow a second network to be routed to the internet.

The network architecture after the change would look as follows:

Steps to follow

1. Add the RUT850 WLAN as a backup WAN to an existing WLAN access point as written in manual
2. Login to RUT850 via SSH
3. edit /etc/config files to move the interface wan2 to the LAN security zone

After the change of the security zone to LAN incoming packets are forwarded to internet. They are treated the same as the packets coming in from access point interface br-lan of RUT850.

/etc/config/network

Search for the station interface and change it from dhcp to a static IP in order to be able to use it as the gateway in the LAN segment it belongs to. I.e.:

config interface 'wan2'
       option proto 'static'
       option backup '0'
       option ifname 'wlan0'
       option ipaddr '192.168.2.254'
       option netmask '255.255.255.0'
       option enabled '1'     
       option disabled '0'  
       option metric '10'

/etc/config/firewall

Remove the interface wan2 from the WAN zone and add it to the LAN zone. Take care that option forward is on ACCEPT for LAN zone:

config zone
       option name 'lan'
       option network 'lan wan2'
       option input 'ACCEPT'
       option output 'ACCEPT'
       option forward 'ACCEPT'

config zone
       option name 'wan'
       option input 'REJECT'
       option output 'ACCEPT'
       option forward 'REJECT'
       option masq '1'
       option mtu_fix '1'
       option network 'ppp wan'

/etc/config/wireless

No changes needed here. Just to show how the station mode wifi interface looks like

config wifi-iface
       option network 'wan2'
       option encryption 'psk2'
       option device 'radio0'
       option key '>your password<'
       option user_enable '1'
       option mode 'sta'
       option scan_sleep '10'
       option ssid 'Maltron1-2.4'