I just connected to NBN recently and have Optus WIFI modem received. The first modem I received I found the LAN port does not work. I called Optus technical support and they said I got faulty modem and they send me another new one. I received the new one today but the LAN port still not working. I tried to use my old ADSL router modem connected to NBN and LAN port connect to my desktop, it works fine. I have the same connection but always cannot get Optus WIFI modem's LAN working. Have anyone have the same problem? Please help. Thank you.
Two modems with the lan port not working suggests there is a configuration issue, not a hardward issue.
The modems should have four lan ports.
Try only plugging a single piece of equipment (a PC?) into one port.
I assume you haven't been able to get to the modem setup page in a browser?
Try set your PC network settings to DHCP (auto) and restart this should ensure your equipment connects.