How does Dynamic NAT (dynamic NAT) and Overloading NAT work? (Part 3)

In Part 1 and Part 2, Network Administrator introduced you to the operation of NAT (Network Address Translation), some types of basic NAT (4 basic NAT types) and NAT configuration. In the next section, Network Administrator introduces Dynamic NAT ( dynamic NAT ) and Overloading NAT .

Dynamic NAT operation mechanism (dynamic NAT):

1. An Internal network ( on a Stub Domain ) is set up with an invalid IP address issued by I ANA (Internet Assigned Numbers Authority). These addresses are considered non-routable addresses because they are not unique addresses.

See also: Understanding the operation mechanism of NAT (Network Address Translation) (Part 1)

1. Set up a NAT - enable the router . Routers are assigned a unique IP address range issued by IANA .

1. A computer on the Stub Domain will connect to an external network computer (Outsie the Network) as a web serve r (Web server).

1. The router receives data packets from the computer on Stub Domain .

1. The router stores the computer's non-routable IP address on the compiled address table. The replacement router will send to a computer with a non-routable IP address that the first IP address is outside the range of unique IP address ranges . The compiled address table will map to the computer with the non-routable IP address of the most appropriate IP address .

1. When a packet is transferred to the destination computer, the router checks the destination address on the packet. Then, the router looks on the compiled address table to see which computer on the Domain Stub contains that packet. The router changes the destination address to an address stored on the address table that compiles and sends that address to the computer. If no matching address is found on the compiled address table, the packet will be discarded.

1. The computer receives packets from the Router. This process can be repeated as long as your computer is communicating with External System .

See also: Understanding NAT configuration (part 2)

Overloading NAT operation mechanism:

1. An Internal Network (on the Stub domain ) is set up with an invalid non-routable IP address issued by IANA.

1. Set up a NAT enabled Router. The router has a unique IP address issued by IANA.

1. A computer on the Stub Domain will connect to an external computer as a web serve r (Web server).

1. The router receives packets from the computer on Stub Domain .

1. The router stores a computer's non-routable IP address and port number (Port number) on the compiled address table. The replacement router sends the non-routable IP address of the computer to the Router 's IP address .

1. The replacement router sends to the computer port the appropriate port number (where the router stores computer address information sent in the compiled address table). The compiled address table maps the non-routable IP address of the computer and the port number to the Router 's IP address .

1. When a packet arrives at the destination computer, the router checks the destination ( destianation port ) on the packet. Then the Router searches on the compiled address table to see which computer on the Domain Stub contains that packet. The router changes the destination address and destination port into an address stored on the compiled address table and sends that address to the computer.

1. The computer receives packets from the Router . This process can be repeated as long as your computer is communicating with the External system .

1. After the NAT router has the source address of the computer and the source port is stored on the compiled address table, the NAT router will use the same port numbers during the connection process. Each time the router accesses an item in the translation address table, it will reset a different hour. If a port is not accessed before the timer runs out, the port will be deleted from the table.

In the next section, Network Administrator will introduce the structure of Stub domain.