The destination filter
The destination filter specifies the packets to which NAT applies based on their destination address, port, or both. NAT applies only to packets that have a destination address, port, or both that match that defined in the filter.
If the destination filter is not specified, then by default, the rule matches packets sent to any destination address and port. The destination filter can be used in SNAT and DNAT rules.
Filtering packets by destination address
The following example shows how to apply a SNAT rule, rule 30, to packets with a destination address of 184.108.40.206. Only packets with a destination address of 220.127.116.11 have address translation performed.
vyatta@vyatta# set service nat source rule 30 destination address 18.104.22.168