NAT Port Table: Address Translation & Exhaustion

Behind almost every home and office firewall sits a Network Address Translation router quietly rewriting outbound packets and keeping a table of who is talking to whom. This simulator renders that table as a live 3D scene: internal hosts on the left fire connections through a NAT router, which allocates external ports from a finite pool and tracks each session until it expires. Push the connection rate and hold time up and the pool runs out — exactly as predicted by the Erlang-B loss formula — while a stream of unsolicited inbound packets shows the flip side: without a matching table entry, the router drops them before they ever reach a host, the mechanism that makes NAT double as an implicit firewall.