The IP_NAT_DIRECTION enumeration contains Network Address Translator (NAT) directions.

 typedef enum _IP_NAT_DIRECTION
 {
   NatInboundDirection = 0,
   NatOutboundDirection
 } IP_NAT_DIRECTION,
  *PIP_NAT_DIRECTION;

NatInboundDirection: The packet was received from a public address and is to be sent to private address.

NatOutboundDirection: The packet was received from a private address and is to be sent to public address.