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Connecting Netgear 4g LTE modem to tpg router and NBN modem settings

Level 2

Dear community,

The background story:

As you all know a lot of people that can work from home due to COVID19. All works well when your NBN works but when it stops then you are out of work. The solution is failsafe backup using 4G LTE modem.

I purchased Netgear 4G LTE LB2120 and a data sim card loaded data on the sim power on the modem did its round of lights flashing then I connected it’s LAN port to my pc LAN port and it worked I had the internet. 4G router has IP address and has 2 ports one is WAN and the other is LAN

My network the router lets call it (TPG Router TP-Link AC1600) with WIFI, WAN port and 4LAN ports has IP with range from to

I’m good with following detailed instructions and not really a network guy.

Now the Problem:

According to the little booklet that come with 4G router all you need to do is once you know your internet works is disconnect the cable from WAN port on my (TPG Router TP-Link AC1600) and connect it to the WAN port on the 4G Modem. That means that my NBN modem is now connected to the WAN port on the 4G Modem.

Connect another cable to the WAN port on my (TPG Router TP-Link AC1600) and the other end connect to the LAN port on the 4G Modem.

This creates a connection that from NBN modem passes throughout the 4G router and the router then decides if there is no NBN to switch to 4G and send the signal to the WAN port on my (TPG Router TP-Link AC1600)

I connected exactly as it was described in the little booklet and as I described here but I don’t have internet on my WIFI and no Internet on my LAN Ports.

So I guess there must be some sort of config that needs to be done on my (TPG Router TP-Link AC1600) or 4G Modem or both. How does this configuration looks like I Don’t know

Please help hopefully with detailed instructions.




Hi Zoro.

The cables go as follows: NBN box to LTE WAN; LTE LAN to TPLink WAN. (Your description is correct but unclear.)
Reconfigure LTE to bridge mode (ip passthrough-no DHCP, no NAT, no port forwarding). NBN box and TPLink think they are directly connected. I suspect the VOIP function might also work in bridge mode. LTE does nothing except for detecting connection down and switching to 4G. You can connect your computer directly to LTE to reconfigure.
The TPLink wifi router should work with just the standard configuration: PPPoE and TPG username and password and VLANID=2 (if you are not on FTTP apparently).

Level 2

Hi David64,

I have the same issue as Zoro and i have tried what you suggested however still no internet access on my land ports the 4g lte modem cannot detect the broadband wireline.





Hi Tom. Sorry but I can't help you. My suggestion to Zoro was only a guess and I don't know if it worked or he went elsewhere for a solution. (The use of VLANID with TPG connection may not be suitable for the 4G connection he has. Or, there may be a problem with the choice of IP address or subnet mask.)

You could send him a private message; click on his name in this thread, sign in to Community and click "Private Message".