Hi said
It depends on how much public ip address you have and the kinda service your are going to host in your location.
You can configure natting based on port numbers using one public ip and natting its ports to different inside ip address ports numbers in which you host your services (like web,mail etc.,).
If you have 100 public ips then you can define a dynamic pool and configure your local inside lan network to make use of the public ip address to go out to reach the outside world.
you can even manage with less no of public ip address and create a dynamic pool and allow your inside network to make use of the public ips based on the availability of the ipz in the pool.
Also if you got to have only one public then simple PAT(overload) will do the rest for you to serve/translate those 100 private ip addresses.
regds
