Network Address Port Translation (NAPT) Overview
NAPT translates a private source IP address to an external source address and port. Multiple private IP addresses can be mapped to the same external address because each private address is mapped to a different 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 Mapping for 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 the external domain, while hiding the private network.
Minimizes the number of public IP addresses that are allocated for NAT.