I did these last night, it's happening, first I disconnect the WAN, and link LAN to my computer, and then link my phone through wifi, both my computer and my phone's ip addr is within 192.168.99.x, I checked it, but when I link WAN to the Internet, all ipaddr changes to 192.168.0.x, and I found my situation is the same as this: [solved] Lose router's gateway when wan is connected