How to setup pfSense with a Cellular Data (4G/LTE) Modem as affordable Failover using Google Fi

This guide is directed at small or medium offices utilizing pfSense to employ Google Fi as an affordable failover internet connection.

Before you read on: As Google Fi’s data-only SIMs only use T-Mobile’s network, we highly recommend you make sure your area has quality 4G or LTE coverage with T-Mobile before investing in this setup.

Hardware Requirements:

  1. pfSense capable device with at least 3 ethernet ports
  2. LTE Modem with ethernet interface
  3. Google Fi SIM Card (data-only SIM being used in this guide)
  4. SIM Card Adapter (if applicable, the modem used in this guide requires an adapter)

As our pfSense device, we’re using the FW1 from ProtectLi, an Intel 4-port firewall/router device.

For our 4G/LTE Modem, we’re using a NETGEAR LB1120 with a data-only SIM from Google Fi. This provides for a setup cost of roughly $120 in hardware and a monthly data cost between <$10 and a maximum of $60 (+$20 charge for the account line, calls and texts). Google Fi charges for the first 6 GB used at $10/GB, after 6 GB / $60 data is free and data after 15 GB is still free but throttled.

This guide assumes you already have a pfSense device configured with at least one functional WAN connection and gateway and a Google Fi account with active service.

Initial LTE Modem Setup

Modem Hardware Setup

  1. Activate your Google Fi SIM by visiting fi.google.com/data and entering the activation code that came with your Google Fi data-only SIM.
  2. The LB1120 has a small panel for inserting your Google Fi SIM. Pop the panel open and put in your SIM by flipping open the locking piece and placing the SIM in the slot using a micro-to-nano SIM adapter.
  3. Place the modem somewhere outside of metal boxes, racks or otherwise for signal through
  4. Connect your modem’s ethernet port to an unused port in pfSense with a patch cable.
  5. Power-on the modem.


Modem Configuration

  1. Login to your pfSense device and visit Interfaces > Assignments. On the Interface Assignments screen, look for the Available network ports dropdown and select the interface your LTE Modem’s ethernet port is connected to. Click Add.
  2. Click the name of the newly assigned interface (should be at the bottom of the list) to start configuring it.
  3. Check ☑ Enable Interface.
  4. Give your interface a descriptive name in the Description field (i.e. ‘FI’).
  5. Set your IPv4 Configuration Type to DHCP. Your IPv6 Configuration Type can remain set to None.
  6. Click Save.
  7. Your interface should come up and pull a DHCP lease from your LTE Modem. The LB1120 comes out of the box with a default setting to act as a router with a default IP address of 192.168.5.1. Automatic outbound NAT should make your modem accessible at http://192.168.5.1
  8. Login to your LB1120 at http://192.168.5.1 with the default password, password
  9. Go to Settings > General > Device and change your Admin login value to a new password.
  10. Go to Mobile > Preferences and make sure Auto Connect is set to Always except when roaming
  11. Go to Mobile > APN and edit the active APN profile. Change the Name to something descriptive like ‘Fi’.
  12. Change the APN to h2g2 (this step is
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