Cisco Systems and the ASA Services Module Manual De Usuario

All NAT rules that are configured as a parameter of a network object are considered to be network object 
NAT rules. Network object NAT is a quick and easy way to configure NAT for a single IP address, a range 
of addresses, or a subnet. After you configure the network object, you can then identify the mapped 
address for that object.

This chapter describes how to configure network object NAT, and it includes the following sections:

For detailed information about how NAT works, see 

When a packet enters the ASA, both the source and destination IP addresses are checked against the 
network object NAT rules. The source and destination address in the packet can be translated by separate 
rules if separate matches are made. These rules are not tied to each other; different combinations of rules 
can be used depending on the traffic.

Because the rules are never paired, you cannot specify that a source address should be translated to A 
when going to destination X, but be translated to B when going to destination Y. Use twice NAT for that 
kind of functionality (twice NAT lets you identify the source and destination address in a single rule).

For detailed information about the differences between twice NAT and network object NAT, see the 

.

Network object NAT rules are added to section 2 of the NAT rules table. For more information about 
NAT ordering, see the