ip nat inside source        
            Translates the source of IP packets that are traveling inside to outside.
            Translates the destination of the IP packets that are traveling outside to inside.

ip nat outside source    
            Translates the source of the IP packets that are traveling outside to inside.
           Translates the destination of the IP packets that are traveling inside to outside.

ip nat inside destination 
             Translates the destination of IP packets that are traveling inside to outside.
            Translates the source of the IP packets that are traveling outside to inside.

ip nat outside destination 
               Translates the destination of the IP packets that are traveling outside to inside.
                Translates the source of the IP packets that are traveling inside to outside.