NAT Port Table 2D: 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 2D companion renders that table as a flat schematic diagram: internal hosts on the left fire connections along straight lines through a NAT router, which allocates external ports from a finite pool drawn as a grid of cells, and a rolling strip chart tracks the measured connection-loss ratio against the Erlang-B theoretical prediction in real time. Push the connection rate and hold time up and the pool runs out — exactly as the two curves on the chart predict — 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.