http://ciisqbg45nggykdl6rjdrq3wc64csga4vkphu66qsi65mypeitqedoad.onion/pfsense
And if you're doing IPv6 too, go to Firewall -> Rules, select the LAN tab, then click the first Add button. On this page, interface should be set to LAN, and Address Family to IPv6, but change Protocol to any. In the Source section, choose Network and set it to your LAN's network (fd00:20:20::/64 in the above example).