Masquerading an address dynamically is NAT (situations where public\external IP address can change, such as those provided by service providers using DHCP)
When masquerading address is STATIC it is called SNAT
Some Tech Stuff
Masquerading an address dynamically is NAT (situations where public\external IP address can change, such as those provided by service providers using DHCP)
When masquerading address is STATIC it is called SNAT