NAPT translates a private source IP address to an external sourceaddress and port. Multiple private IP addresses can be mapped to thesame external address because each private address is mapped to adifferent port of the external address.
With NAPT, you can configure up to 32 external address ranges,and map up to 65,536 private addresses to each external address.
NAPT supports the following:
Round-robin port and address allocation (see Round-Robin Port Allocation).
Address pooling and endpoint independent mapping (see Address Pooling and Endpoint Independent Mappingfor Port Translation).
Secured port block allocation (see Secured Port Block Allocation for Port Translation
Benefits of NAPT
Allows hosts in the private network to connect with theexternal domain, while hiding the private network.
Minimizes the number of public IP addresses that are allocatedfor NAT.