Santos:CCNA Sec 210-260 OCG

Port Address Translation

Port Address Translation (PAT) is a subset of NAT, and it is still swapping out the source IP address as traffic goes through the NAT/PAT device, except with PAT everyone does not get their own unique translated address. Instead, the PAT device keeps track of individual sessions based on port numbers and other unique identifiers, and then forwards all packets using a single source IP address, which is shared. This is often referred to as NAT with overload; we are hiding multiple IP addresses on a single global address. When all those packets come back, they return to unique port numbers. Fortunately, the PAT device has been keeping track of which clients from which IP addresses initiated which sessions. So, referring ...