The following three situations are representative of those I have encountered in the real world. Each is designed to demonstrate what people typically do with NAT and how the situations would be implemented on the chosen platform.
Creating a Simple Network with NAT
You work for a small company with a few hosts on a flat network segment. Your firewall runs on a Windows NT platform. The ISP has given you only a /29 net block, which effectively gives you six hosts you can use on the outside segment. Because the firewall and Internet router each need a unique IP address, this leaves a total of four addresses that can be used for other hosts (see Figure 10.8).
Figure 10.8. Simple network with NAT