> Nothing is stopping an ISP from implementing it by taking one ip and assigning ports 1-10.000 to customer A, 10.001 - 20.000 to customer B, and so on. Similarly, nothing is stopping an ISP from adding long-lived mappings to an otherwise-random pool which outlive the initial connection.
I’m pretty sure that the scarcity of Legacy IP addresses and port numbers (!) is exactly what stops providers from doing that, at least by default. I’ve seen NAT running out of ports way too many times, and shortening of connection tracking lifetime comes with a whole set of hard to spot bugs.
I’m pretty sure that the scarcity of Legacy IP addresses and port numbers (!) is exactly what stops providers from doing that, at least by default. I’ve seen NAT running out of ports way too many times, and shortening of connection tracking lifetime comes with a whole set of hard to spot bugs.