juniper netscreen nat策略问题

lxl1989

set policy id 203 from "Trust" to "Untrust"  "21.123.66.90ATMMM服务器" "21.33.133.12/32万达ATM（西门）" "ANY" nat src dst ip 199.168.5.52 permit log    求大神们帮解释一下这条策略，重点是后面的 nat src dst ip 199.168.5.52 是将源和目的地址都转换成199.168.5.52吗？