In large NATTED networks, where the number of LAN devices create more connections than there are available ports, connections will stop working, and internet access will be intermittent due to port exhaustion.

Example: In a standard NAT setup on Mikrotik, NATTED connections each get one src port. By default Mikrotik NATS using the port range (1024–65535) – If the total amount of active connections out number ~64 thousand (ignoring any static ports), then the network will have exhausted all available ports, and subsequently new connections will not be possible until used ports become available again after connection timeouts.

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