Because of the need for increased security, many businesses use a form of network protection called a firewall to prevent unauthorized access to or from their private networks. Firewalls can be software or hardware based, or they can be comprised of a combination of both. Part of this protection can include the use of a device or application called NAT.
NAT, or Network Address Translation, is an Internet standard that enables a local-area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations. Additionally, NAT provides a type of firewall by hiding internal IP addresses, and it enables a company to use more internal IP addresses. Since they are used internally only, there is no possibility of conflict with IP addresses used by other companies and organizations.