Central NAT table default behavior

[ping]

Hi,

what is the default action if the traffic that flow through the Central NAT table doesn't match any rule? In my test, if in the policy is enable NAT with flag " Central NAT Table" and the network traffic that pass through it doesn't match any rule, the firewall nat the source address with the IP address of the exit interface. It is possible to change the behavior of the firewall in this situation? I don't want any source address nat if no rule is matched on the Central NAT rules.

Thanks in advance, sorry for my bad english.