Re-post from LYN forum. Credit to ansonlos.

After much try and error and research, I’ve managed to get pfSense to work with UniFi’s IPv6 allocation. For a bit of a background, I’m running the latest release of pfSense i.e. 2.2.1 and also I got this to work with my office’s UniFi which is on Biz 10.

I’d just like to share my settings here to benefit those who might want to get IPv6 to work for their pfSense box.

1. Under “System -> Advanced -> Networking”, make sure “Allow IPv6” is checked. Then go to “Interfaces”, click on “WAN”. Under IPv6 Configuration Type, choose “DHCP6”. MTU should be 1492.

2. Under DHCP6 client configuration section, put a tick mark on “Request a IPv6 prefix/information through the IPv4 connectivity link”. In the drop down list for DHCPv6 Prefix Delegation size, choose “56”. (I have no idea why this is the case, but the allocated subnet for both the PPPoE and LAN are actually 64. I’ve tried choosing 64 here, but it doesn’t work. Maybe 56 is for a Biz account. If 56 doesn’t work for you, try choosing 64 especially if you’re on home UniFi account.)

Also, put a tick mark for “Send an IPv6 prefix hint to indicate the desired prefix size for delegation”. Click on “Save”.

3. Now, go to “Interfaces”, click on “LAN”. Under IPv6 Configuration Type, choose “Track Interface”. Type 1492 for MTU.

4. Under Track IPv6 Interface section, ensure IPv6 Interface “WAN” is selected and as for IPv6 Prefix ID, just type 0 (zero) here.

5. Under Private networks section, ensure “Block Bogons networks” is unchecked. Then, click “Save”.


6. Finally, I’ve read that IPv6 requires ICMP to work. So under Firewall -> Rules, I’ve also created a rule to allow ICMP IPv6 traffic for both WAN and LAN.

I’m not entirely certain what the security implications are with the above settings to the firewall, so please be forewarned.

With the above settings, I’m able to get IPv6 addresses for PPPoE and LAN interfaces for pfSense and also devices connected to the LAN. Hope this helps those who are using pfSense.

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