These directions have been tested on libreCMC 1.5.13 with a mini wireless router v2 and v3, a Penguin USB 4G LT4120 modem in the United States set to QMI mode, and using an AT&T reseller as the cellular provider. Which provider you go with shouldn't matter. Just make sure the 4G modem is working via the router and the below should work to get VPN working. These directions should also work just fine for those with a Penguin USB 4G EM7455 modem too so long as it again is set to QMI mode.
Note: These are our older directions below. For our newer PenguinVPN 2.0 service that supports Wireguard follow the directions at https://www.thinkpenguin.com/gnu-linux/connecting-penguinvpn-using-wireg... and make sure to utilize the directions farther down the page under the title "These lengthier more complete directions explain how to setup the router from scratch rather than a default VPN configuration archive" (as the default VPN configuration is for those who are using ADSL/Cable WAN connection, not for those using a USB 4G modem). Before you follow those directions though make sure to follow the directions for setting up the router to connect via your USB 4G modem.
Step 1: Setup your router to work with the 4G modem using our standard directions to do that:
https://www.thinkpenguin.com/gnu-linux/usb-4g-lte-advanced-modem-router-...
Step 2: Download the PenguinVPN configuration that is for use with our libreCMC routers which are connecting to the internet via our USB 4G modems:
https://www.thinkpenguin.com/files/tpe-r1200-PenguinVPN-default-vpn-conf...
Step 3: Extract the tpe-r1200-PenguinVPN-default-vpn-configure-for-1.5-onward-parabola-server-for-use-with-4g-modem.tar.gz file and edit the key.txt file in the etc/openvpn folder. You need to enter your PenguinVPN user name and credentials here. Save the file and compress the etc folder. Make sure you save in the tar.gz format/file extention. Otherwise the router can't extract the contents upon upload in the following steps.
Step 4: Make sure you have the SIM card inserted in the 4G modem and it's already been activated, then connect your USB 4G modem to the router's USB port, then connect the ethernet cable from the LAN port on the mini wireless router and the other end to a computer. Connect the power.
Step 5: Login to the routers user interface (default password is the word 'none', you may have to accept a security warning and add an exception too) via opening a browser and going to https://192.168.8.1
Step 6: Go to Network > Interfaces and click the edit button for the WWAN0 interface. In the APN box make sure you have the APN name for your cellular provider entered. Click the Save & Apply button.
If you don't know the APN info for your provider we have directions for specific providers on the networking page. Pull up the page for your provider and write down the APN name found in the directions. Note: you don't need to follow the directions. This is just for reference to obtain the APN name for the provider. If it's not a provider listed use a search engine to find out or contact your cellular provider to find out what the APN name is. After that go to System > Reboot.
Step 7: Give the router a chance to reboot and connect to the internet via the USB 4G modem. Then open a new tab in your browser and go to https://infosniper.net and make sure the internet connection is working via the USB 4G modem before going any further.
Step 8: Once you know the 4G modem is working go to System > Backup / Flash Firmware and under the Restore section click browse and select the compressed tar.gz file containing your edited key.txt file. Click the upload button.
Step 9: Go to Network > Interfaces
Step 10: Click Add new interface... button
Step 11: In the Name of new interface box enter VPN
Step 12: In the Cover the following interface drop down enter tun0 under Custom Interface
Step 13: Click Submit button
Step 14: Go to Network > Firewall
Step 15: Click Add button
Step 16: In the Name box enter VPN
Step 17: In the Input, Output, and Forward box select Accept
Step 18: Make sure the boxes that say Masquerading and MSS clamping are checked. If not give them a check.
Step 19: Under Covered networks select VPN:
Step 20: Under Allow forward from source zones: select lan: lan:
Step 21: Click Save & Apply button
Step 22: Go to Network > Interfaces and Click the Edit button next to VPN
Step 23: Make sure the the box that says Bring up on boot is checked. If it isn't check the box.
Step 24: Under Use custom DNS servers enter 8.8.8.8 and then click the + button
Note: You don't have to use 8.8.8.8 for the DNS. This is Google's DNS and another DNS provider is probably preferable. It's a good DNS to use for testing purposes as it's pretty reliable. Not all DNS providers are super reliable.
Step 25: Go back and make sure you clicked that + button... otherwise the DNS settings won't be saved.
Step 26: Click the Save & Apply button
Step 27: Go to Network > Firewall
Step 28: Under Zones click Edit button next to lan > wan VPN
Step 29: Remove wan: WWAN0: from Allowed forward to destination zones: drop down
Step 30: Click the Save & Apply button
Step 31: Go to System > Reboot and click the Perform Reboot button
Step 32: Give the router a minute or two to reboot and your 4G modem to connect to the internet as well as the VPN connection itself to be established. Then open a new browser tab and go to https://www.infosniper.net and check to see if your cellular provider is shown as the Provider. If it is then your not connected via the VPN. If you are not seeing your cellular provider then chances are you are connecting through the router, the 4G internet, and VPN. If it says some random country that you aren't in that's another good indicator you are connecting through the VPN.