I have tried packet tracer and actual cisco routers and I find this weird: NAT uses different source ports, usually incrementally, for consecutive packets from the same connection. Why is that?
Assume I am pinging an external server from a client on my private network. the client PC sends 3 ICMP echo-request packets. When I check out the NAT translations table on the router, there are 3 entries; from the same source IP address to the same destination IP address but each have a different port number. Shouldn't there be just one entry? BTW, that is the case with different kinds of NAT including dynamic NAT and PAT.