Where to use IP Passthrough?

I have two Pepwaves connected to each other. A Pepwave MAX BR1 MK2 and a second BR1 MINI connected via Ethernet (LAN of MINI going to WAN of BR1 MK2). I have cellular SIM cards in each unit. I was told to check IP Passthrough and I did that on the Cellular connection on the BR1 MINI. I also see there is an IP Passthrough on the WAN connection on the WAN connection of the BR1 MK2 (which is the 2nd pepwave).

Where exactly am I supposed to be using IP Passthrough? The Cellular connection on the BR1 MINI and/or the WAN connection of the BR1 MK2?

Thanks.

I’m not 100% certain I understand your configuration but a comment or two might help …

If you are using one BR1 essentially as a modem you probably do not want it to be a NAT router. So, the device that is connected to cellular on the WAN side and to another BR1 on the LAN side should probably be set as “IP passthrough” so as to avoid “double-NATIng.” However the BR1 to which your user devices (computers, etc) are connected should NOT have this box checked as we want the NAT firewall to be operational and we want to be able to serve multiple addresses on the LAN side.

Make sense?

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Thanks, yes, that’s how I have it set now. On the secondary Pepwave (BR1 MINI) that’s connected to the primary Pepwave WAN port the cellular has IP Passthrough checked.

I was wondering though if on the WAN connection of the primary Pepwave if that should also have IP Passthrough checked? It is NOT at this time.

Hi. I’m having a bit of difficulty with the terms “primary” and “secondary” but I think I understand the arrangement. If the 'Primary" device is the one to which your user devices are connected on your LAN you probably do NOT want “IP Passthrough” checked. Doing so will defeat the NAT firewall and serve a single IP address to the LAN side.

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it should not be checked. The mk2 is providing DCHP to all of your clients. Enabling IP Forwarding would cause the modem to only offer one public IP and most of your devices would stop working. You seem to have this setup properly.