Outside of the corporate environment, one of the biggest enticements of firewall technology to the end user is the ability to connect several computers through a common external interface, often without the approval, knowledge, or even consent of their service provider. To those familiar with Linux, this concept is called IP Masquerading, but to the rest of the world it is known by the more obscure name of Network Address Translation, or NAT for short.[[dagger]] [[footnote: [[dagger]] To be pedantic, what IPFilter provides is really called NPAT, for Network and Port Address Translation, which means we can change any of the source and destination IP Addresses and their source and destination ports. True NAT only allows one to change the addresses. ]]