Source NAT can do address translation with or without port
address translation (PAT). The source port pool type indicates
whether the address translation is done with port or without
the port, or if it is a static translation.
withPAT(Source Pool with PAT): the security device translates
both source IP address and port number of the packets
withoutPAT (Source Pool without PAT): the device performs source
network address translation for the IP address without
performing port address translation (PAT) for the source port
number.
Static translation means that one range of IP addresses is
statically mapped one to one to a shifted range of IP addresses.