Me too. I’ve always wondered how a NAT knows where to route traffic. I figured it would use a lookup table, but I never know what the “keys” were. For some reason, using different ports for each device behind the NAT never crossed my mind! I knew it couldn’t be done by adding routing data to the packets (which is what IPv6 ended up doing) because that isn’t sustainable over multiple NATs. A port based routing with a table makes so much sense! It also explains why idle sessions are dropped.