Just fine? NAT at the end of the day is a glorified stateful firewall, but it's even worse because of the overhead of mapping (src, port) pairs to other (src, p

Just fine? NAT at the end of the day is a glorified stateful firewall, but it's even worse because of the overhead of mapping (src, port) pairs to other (src, port) pairs and the mess of rewriting packets (which breaks in really fun way with protocols like SIP). You can get the same protection NAT offers for IPv6 with an incredibly basic set of firewall rules, only allowing devices on the LAN side of the connection to establish connections and punching holes where necessary.