LB2120 need configuration help

[rramstad]

I have what seems to be a really mysterious configuration issue with LB2120.

I want to use it for failover.  I have it in bridged mode.

When I directly cable the unit (LAN port on the back to my desktop, nothing connected to WAN) I have absolutely no trouble accessing the internet.  All green lights on the front, and the device works great, and I can log into the web interface.

When I put the unit in between my cable modem and my ASUS router, cable modem to WAN, ASUS router to LAN, we end up with no internet connection on the LAN, none whatsoever. When I disconnect the WAN cable, I get SMS alerts saying the WAN is down, but I still have no internet connection on the LAN.

I am therefore completely baffled.  I suspect that I need to change the configuration on other devices, but I am at a loss.  I've spent a lot of time experimenting, and I have to believe that this is trivially simple, and I'm just missing something...  I mean, I'm trying to do exactly what the device is designed to do, and my hardware isn't anything unusual, and I can't get it to work.

So, I'd love it if people could either share the configuration that is working for them OR suggest a couple of things to try in terms of configuration.  Thanks.

[navlrac]

Just a thought, but bridged mode with fail-over may need special support on your upstream router or PC?
In bridge mode, you get the WAN IP address on the LAN side. When fail over happens, the Mobile network becomes bridged which most certainly has a different IP. Unless the LB2120 suddenly started doing NAT during fail over, you would need to get the new IP on the LAN side otherwise you may continue using the WAN's IP.

See whether it works in router mode?

[rramstad]

I did some additional testing with this unit and have been able to get it to work more or less. I cannot get it to work in bridging mode. It will work in routing mode but I had to reconfigure my internal router for that to work. (I had to change the WAN on the internal router to match the range expected by the Netgear device, so they could talk to each other.)

That said, the one strange bit is that inbound VPN traffic -- from the public internet to my LAN though all the devices -- works fine when the system is connected through the cable modem, but if the cable modem is off, even when all the IP addresses update and everything, I cannot VPN in.

It seems to be something either in the configuration on the Netgear device OR possibly some issue with AT&T.

In any case, I'm not thrilled that I have double NAT within my building just to get outside, but conversely, the Netgear device is providing (sort of) failover.

The remaining major issue is that inbound VPN does not work when the broadband modem is down and we're using the cell connection.

Any insight into that (and possibly, any ideas as to how I might get bridging mode to work) would be helpful.

Netgear support has asked a million questions but hasn't provided any answers on any of this... it's all been raw experimentation.

[jlfulcherjr]

I also have the same issue... AT&T says it can't share a connection ..that is why they have their own custom device but I was trying to save some money,,,I Thought.  My be just a design flaw,,In any case it works great as a stand alone Ethernet connection to the web...

[LucianZ]

I have the same issue, in bridge mode as an failover solution is not working. In router mode is working fine, but if you want to use it in bridge mode as a backup internet connection will not work. In order to use it I ended up with buying a Linksys router with 2 WAN and use LB2120 as a simple LTE modem.