× Some paid Circle Parental controls customers may be showing free options only. Router firmware correcting this issue will be available ASAP. Visit Status.NETGEAR.com for updates.

Discussion stats
  • 1 reply
  • 0 kudos
  • 2 in conversation


Using a Netgear LB2120 4G modem with Netgear D6400 router



Not sure if anyone has any experience with setting up a LB2120 to act as a failover for a D6400.

I have pugged the LB2120 into my PC port directly and the WAN port to the D6400 it is configured in bridge mode with an IP address in the same subnet and fails over if I disconnent the WAN port.

However it doesn't always fail back to the D6400 without resetting it.

I would like this to be a bit more automated and act as a genuine failover for all devices connected to the D6400 rather than just my PC.


The D6400 is connected to the internet via the vDSL port using SKY superfast fibre (which has been very reliable)

I work full time from home and with everything that is is goig on right now, and people being isolated to their homes to work from home, I would like to ensure that I always have a connection so that I can carry on working.

Hence getting a 4G backup solution.


I found this which is close to what I am asking but nothing confirmed to be working/not working



The D6400 has both a WAN port and a DSL port and there is configuraion (WAN Preference) to use either and an auto-detect option. Does the auto detect auto switch between the WAN & DSL and which one will it choose?

Would it be best to plug the LB2120 into the WAN port (WAN port to WAN port) or WAN port on the LB2120 to a LAN port on the D6400?

If LAN then how will it handle DHCP? should I split the DHCP range in two 50/50 between both the D6400 and the LB2120?


Is the configuration I am looking at even possible with these routers?


Perhaps I need a different router? but disinclined to do so as I am really happy with the D6400


Any feedback advice greatly appreciated.








Model: D6400|AC1600 WiFi VDSL/ADSL Modem Router?802.11ac Dual Band Gigabit, LB2120|4G LTE Modem
Message 1 of 2

Re: Using a Netgear LB2120 4G modem with Netgear D6400 router

I don't think the D6400 supports autofailover. The only consumer router I know is the R7100LG

Message 2 of 2