Benefits of NAT

More IP addresses Available while Conserving Public IP Addresses

As explained earlier, this was the original intent of the technology and does not need to be gone into further.

Financial Savings

Because an organization does not have to purchase IP addresses for every computer in use there is a significant cost savings due to using the process of Network Address Translation.

Security Enhancements

One of the side benefits of the process of NAT is an improvement in security. Individual computers are harder to target from the outside and if port forwarding is being used computers on the inside of a firewall are less likely to have unmonitored open ports accessible from the Internet.

Ease of Compartmentalization of Your Network

With a large available pool of IP addresses to use internally a network administrator can arrange things to be compartmentalized in a rational and easily remembered fashion and networks can be broken apart easily to isolate for reasons of network performance and security.

Example

You have a large organization that for security reasons has certain departments that do not share network resources.

You can have the main section of the organization set up as follows;

You could then have the following groups broken off into separate subnets:

These addresses do not have to be assigned right away but can be used as planned ranges.