In my country, everyone who provides Internet to any user needs to record log of user's usages. (For example, log-in & log-out date time, Src-IP & Dst-IP, etc) For my case based on tomato, I would like to NAT each user to each range of Wanort. For example user A (DHCP with 192.168.1.100), all traffic would be done NAT to Wan-IP and port number 10,000 - 20,000. What is a iptables command can get it work? Thank you for help.