Static Source NAT Overview
Static source NAT performs a one-to-one static mapping of the original private domain host source address to a public source address. A block of external addresses is set aside for this mapping, and source addresses are translated as hosts in a private domain originate sessions to the external domain. Static source NAT does not perform port mapping. For packets outbound from the private network, static source NAT translates source IP addresses and related fields such as IP, TCP, UDP, and ICMP header checksums. For inbound packets, static source NAT translates the destination IP address and the checksums.
Benefits
Allows hosts in the private network to connect with the external domain, while hiding the private network.