IP NAT pool range

Question

When is it necessary to setup a pool of more than one address?

So if I have this ip pool range:

ip nat pool demo 72.32.11.65 72.32.11.66 netmask 255.255.255.252

What's the difference if I just have one address?

ip nat pool demo 72.32.11.65 72.32.11.65 netmask 255.255.255.252

Answer 1

If you're using overload (PAT), it only makes a difference if you make very many (tens of thousands) of simultaneous outbound connections. If you're not using overload, you'll need one outside global IP address per inside local IP address that will be translated through that pool.