<p>This article describes frequent terms and brief description of the NAT gateway product of Ping An Cloud.</p> <table border="1" cellpadding="0" cellspacing="0" style="width:0px"> <tbody> <tr> <td style="background-color:#ededed; width:171px"> <p><strong>Terms</strong></p> </td> <td style="background-color:#ededed; width:612px"> <p><strong>Description</strong></p> </td> </tr> <tr> <td style="width:171px"> <p>NAT</p> </td> <td style="width:612px"> <p>Network Address Translation, which enables the intranet with Internet access ability by translating the private IP to the public IP address.</p> </td> </tr> <tr> <td style="width:171px"> <p>SNAT</p> </td> <td style="width:612px"> <p>Source NAT is a type of network address translation. It translates the private IP assigned by the cloud server in the VPC into the public IP address and builds the access to the Internet. Thus, multiple cloud server instances in designated subnet of the DMZ in the VPC can access the Internet through one or multiple designated public IP addresses.</p> <p>SNAT is initiated by the private IP to enable shared IP addresses on the intranet to assess the Internet. It provides only active access to the Internet, rather than external services to the Internet.</p> </td> </tr> <tr> <td style="width:171px"> <p>DNAT</p> </td> <td> <p>Destination NAT is a type of network address translation. It maps the private IP of the cloud server in the VPC to the public IP address and allows designated ECS instances to provide services to the Internet or to access the Internet by using designated public IP.</p> <p>DNAT supports two modes, including IP mapping and port mapping.</p> </td> </tr> <tr> <td style="width:171px"> <p>IP mapping</p> </td> <td> <p>IP mapping maps the private IP to the public IP address to allow designated ECS instances to access the Internet through designated public IP address. IP mapping provides active and passive access ability to the Internet. The access request to the Internet can be initiated from both the ECS in the VPC or the Internet client. But this method cannot save the public IP address.</p> </td> </tr> <tr> <td style="width:171px"> <p>Port mapping</p> </td> <td> <p>Port mapping maps a port of the public IP address to the ECS of the intranet and allows the designated port of designated ECS instance to access the Internet through designated public IP address and port. Port mapping can maximize the use of a single public IP. Port mapping connection is initiated by external addresses, and is mainly used for the external release of intranet services.</p> </td> </tr> <tr> <td style="width:171px"> <p>Bandwidth package</p> </td> <td style="width:612px"> <p>Bandwidth package is the Internet bandwidth resource purchased by users. It features bandwidth sharing and multiplexing function.</p> </td> </tr> </tbody> </table>