Real Address: The real address is the address configured on the host device. In a typical set-up, the real address might be an IP address configured on a server connected to the inside interface of a firewall.
Mapped Address: The mapped address is the address the real address is translated to. In a typical set-up, this would be the public outside address of a firewall.
Dynamic NAT: A group of real addresses are translated to a group of mapped addresses on a first-come, first-served basis. The mapped group of addresses is usually smaller. Only the real hosts can initiate traffic.
Dynamic Port Address Translation (PAT): A group of real addresses are translated to a single mapped IP address each with an associated unique port number.
Static NAT: A one-to-one translation between a real IP address and a mapped IP address.
Identity NAT: A real address is translated to itself, so in effect not translated. This is used when you what to switch off NAT for a specific real IP in a group.
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