NAT Editor
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8/28/2008
A device that runs Network Address Translation (NAT) is a gateway between the Internet and a home network. In order for the gateway to provide devices on the home network with full access to the resources of the public network, packets need to move fluidly across the gateway that runs NAT. A gateway that runs NAT translates information in packets that move across the gateway, converting an IP address and port for a device on the home network to an IP address and port for the public side of the gateway machine. These port mappings allow devices on the home network to share one public-side IP address.
The NAT driver is responsible for translating address and port information for Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) traffic. Certain kinds of protocol traffic, however, cannot be translated by the NAT without further information. The following kinds of protocols cannot be translated without further information:
- Protocols that involve unsolicited connection requests, or UDP data channels, from the public network.
- Protocols that embed network address or port information in the data stream.
Examples of protocols that have these characteristics include File Transfer Protocol (FTP) and Point-to-Point Tunneling Protocol (PPTP). The NAT driver handles these two protocols internally. To handle other protocols that have the previously listed characteristics, OEMs can create a specialized NAT editor that examines network packets to obtain the information needed to translate the protocol traffic.
See Also
Concepts
Network Address Translation
NAT Editor Operation
NAT Editor Initialization and Registration
NAT Editor Functions
Packet Data Handling and Editing