IP NAT Registry Settings

The following table shows the named values for the HKEY_LOCAL_MACHINE\Comm\IPNAT registry key that you can use to configure IPNAT.

Note   The default registry values vary depending on which features are included in your platform. For more information, see Default Registry Settings.

Value : type Description
ReservedPortsEnd : REG_DWORD Default setting is 0x0BB8 (3000).

Specifies the end of the reserved range of TCP of UDP ports used by NAT in port translation. The valid range for this value is 0 to 0xFFFF, and must be greater than or equal to the value of the ReservedPortsStart subkey.

This registry value is interpreted as a hexadecimal number. NAT reads port numbers and converts the port numbers to host byte order, instead of using network byte order. Host byte order means that the bytes are stored with the same byte ordering that the host uses. Network byte order means that the bytes are stored in big-endian order. Windows CE–based computers are currently all little-endian, so host byte order stores the bytes in reverse order. For example, you would specify the bytes for port 42045 (0xA43D) in the order A4, 3D when using network byte order, and in the order 3D, A4 when using host byte order. You can change a value from network byte order to host byte order by calling the ntohs function, and you can change a value from host byte order to network byte order by calling the htons function.

ReservedPortsStart : REG_DWORD Default setting is 0x0401 (1025).

Specifies the start of the reserved range of TCP of UDP ports used by NAT in port translation. The valid range for this value is 0 to 0xFFFF, and must be less than or equal to the value of the ReservedPortsEnd subkey.

This registry value is interpreted as a hexadecimal number. NAT reads port numbers and converts the port numbers to host byte order, instead of using network byte order. Host byte order means that the bytes are stored with the same byte ordering that the host uses. Network byte order means that the bytes are stored in big-endian order. Windows CE–based computers are currently all little-endian, so host byte order stores the bytes in reverse order. For example, you would specify the bytes for port 42045 (0xA43D) in the order A4, 3D when using network byte order, and in the order 3D, A4 when using host byte order. You can change a value from network byte order to host byte order by calling the ntohs function, and you can change a value from host byte order to network byte order by calling the htons function.

TcpTimeoutSeconds : REG_DWORD Default set to 0x15180, or 86400 seconds (24 hours).

Specifies the amount of time in seconds before TCP mappings expire in the NAT. The valid range for this value is 0 to 0xFFFFFFFF.

The internal timer in the NAT runs once per minute to delete expired mappings.

UdpTimeoutSeconds : REG_DWORD Default set to 0x3C, or 60 seconds.

Specifies the amount of time, in seconds, before UDP mappings expire in the NAT. The valid range for this value is 0 to 0xFFFFFFFF.

See Also

Internet Connection Sharing Registry Settings

 Last updated on Thursday, April 08, 2004

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