pfSense

Add a host alias, in the IP Address or FQDN box of the 1st entry put:

1:2:3:::4:5:6:8 or 1:2:3:4:5:6:::8 or similar stuff with a triple colon in the middle somewhere.

It validates, but then when the ruleset is written causes "error loading the rules".

Net_IPv6::checkIPv6("1:2:3:::4:5:6:8");
returns true,
so it's a bug in the Net_IPv6 code.

I am happy to have a look tomorrow and sort out what is going wrong with the Net_IPv6 code when faced with more than 2 ":" in a row.