Address pool problem in pat configuration

flypanda999

GNS3 and PT are used to configure pat respectively. The public network address is expressed in the form of address pool, and Pt is used to configure pat

ip & nbsp; nat & nbsp; pool & nbsp; xxx & nbsp; 100.1.1.1 & nbsp; 100.1.1.1 & nbsp; net & nbsp; 255.255.255.255
No problem, but when it comes to GNS3, the same statement prompts me that the longest mask is / 30, not / 32

Which is right??? I personally think that since the public IP assigned by PPPoE can be / 32 in pat, and the public IP address in static NAT can also be / 32, pat should also allow the public IP address of / 32. If the starting IP and the ending IP in the pool are equal, can I use the mask of / 32.