Route all traffic over other router in LAN (For RA without WAN connection)

Step 1: Go into the web interface of the Peplink router and login.

Step 2: Go to Network tab and go into the Network Settings.

Step 3: Here you need to configure a Static router with Destination Network 0.0.0.0 (All IP traffic) Subnet Mask 0.0.0.0/0 and as Gateway the IP address of a router with internet that is in the LAN of this Peplink router (192.168.50.100 for example)

Step 4: Click on the blue circle with the question mark and click the option to reveal the Advanced settings for DNS resolvers.

Step 5: Check the Untagged LAN and set the preferred DNS Server.

Step 6: Click on Save at the bottom of the Network settings. When the settings are saved on Apply Changes in the top right.