What is the maximum number of configurable NAT IP pools (ip nat pool “name”)?

In practical use, the maximum number of configurable IP pools is limited by the amount of available DRAM in the particular router. (Cisco recommends that you configure a pool size of 255.) Each pool should be no more than 16 bits. In 12.4(11)T and later, IOS introduce CCE (Common Classification Engine). This has limited NAT to only have a maximum of 255 pools. In 12.2S code base, there is no maximum pools restriction.