Shared address space (100.64.0.0/10)
termISP & telecomnetworking
The IPv4 range reserved for the middle layer of carrier-grade NAT, between the subscriber's own private network and the provider's public addresses.
It exists because providers were previously borrowing ordinary private ranges for this purpose, which collided with the ranges customers were already using at home and produced faults nobody could diagnose from either end. Treat an address from this range as a signal rather than a destination: it means the customer sits behind provider translation, so inbound connections will not work and the address does not identify a household.
Also known as: 100.64/10, rfc 6598, nat444 middle layer