Note: Our stock USB 4G modem configuration already has IPv6 enabled by default, and these directions are only applicable if you have followed the directions we have for turning off the VPN service (where your using a 4G modem + PenguinVPN configuration, directions to turn off the VPN are here and should be followed first).
The below directions were last vetted under libreCMC 6.4.
Enabling IPv6
0. Turn off the VPN
1. Back in the luci web user interface for the router Under Network > Interface click the Edit button for the LAN
2. Go to the Advanced Settings tab and change IPv6 assignment length from disabled to 60
3. Check the box Delegate IPv6 prefixes
4. Under the DHCP Sever section go to the IPv6 Settings and select server mode in the drop down for RA-Service and server mode for DHCPv6-Service
5. Click the Save button and Save & Apply button
6. Go to System > Reboot and click the Perform reboot button
7. After the router reboots go to Network > Interfaces > LAN > DHCP Server > Advanced Settings > "Force DHCP on this network even if another server is detected" (uncheck). Click the Save button. Click the Save & Apply button.
8. System > Reboot and click Perform reboot button
9. Click on your network applet and disconnect from the network, then click the applet again and reconnect to the network
Open up a terminal window on your computer and run ping6 google.com and you should get output similar to below where it says 0% packet loss and it shows an IPv6 address:
think@penguin:~$ ping6 -c 4 google.com
PING google.com (2a00:1450:4009:819::200e) 56 data bytes
64 bytes from lhr48s09-in-x0e.1e100.net (2a00:1450:4009:819::200e): icmp_seq=1 ttl=113 time=118 ms
64 bytes from lhr48s09-in-x0e.1e100.net (2a00:1450:4009:819::200e): icmp_seq=2 ttl=113 time=126 ms
64 bytes from lhr48s09-in-x0e.1e100.net (2a00:1450:4009:819::200e): icmp_seq=3 ttl=113 time=132 ms
64 bytes from lhr48s09-in-x0e.1e100.net (2a00:1450:4009:819::200e): icmp_seq=4 ttl=113 time=123 ms
--- google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3005ms
rtt min/avg/max/mdev = 117.701/124.580/131.923/5.150 ms
You can also open a web browser and go to infosniper.net and it should show you a IPv6 address.