Your employer has several thousand internal users all who need to access the internet on a daily basis to complete their work. What technology should be used to mask the internal IP addresses of these users and allow access to the internet through shared public IP addresses?
Answer Description
Network Address Translation (NAT) allows many devices to share an IP when accessing another network. Most commonly it is used to allow internal devices to share public IP addresses when accessing the internet. Benefits of NAT include minimizing the number of public IP addresses required (they cost money and for IPv4 there is a limited number available) as well as masking the origin of the request which provides security benefits. Generally NAT is used on a router or firewall.
Wikipedia
Network address translation (NAT) is a method of remapping one IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device. The technique was originally used as a shortcut to avoid the need to readdress every host when a network was moved. It has become a popular and essential tool in conserving global address space in the face of …
Network address translation - Wikipedia, the free encyclopedia