I understand this part :) I use a fairly complex firewall at work though I only know bits and pieces from reading different manuals. I think the part I didn’t understand was how exactly the routing worked differently in IPv4 vs v6. I get that because NAT happens in IPv4, packets can’t be routed at all without the firewall/router but I wasn’t sure what was the mechanism by which v6 made sure that packets went through the router, especially when you have stuff like v6 DHCP relays.
Yeah. Like the character in memento I suppose, albeit in a subtler way.