Network Address Translation
External/
Internal/
OVERLOADING
In Overloading, each computer on the private network istranslated to the same IP address; that of the NAT externalinterface, but with a different port number assigned.
1.Private host generates an IPpacket that gets sent to the NATrouter. NAT removes the privateIP address from the packet andputs the public IP address intothe packet.
2.NAT appends a randomlyassigned port number to thepublic IP Address.
3.NAT stores the private IPaddress and the port assigned ina table for future reference.
4.NAT forwards the packet to thepublic network.
5.When the host on the publicnetwork responds, NAT uses thetable to see which privateaddress the packet should go to.
6.NAT replaces the public addresswith the private IP address of thehost that originated thecommunication and forwards thepacket to the private network.
7.When the session is completed,the port is returned to the pool tobe reassigned as needed.
STATIC
In Static NAT the computer with an IP address of 10.0.0.2will always translate to 209.5.1.2.
DYNAMIC
In dynamic NAT, any computer on the private network willtranslate to an available address in the range from 209.5.1.2to 209.5.1.50
209.5.1.2to209.5.1.50
