A：
Currently only CLI command can support the settings of Multi-NAT. It is useful when you have over than one public IP address and want to setup two servers at LAN site. And these servers will provide the same service and use standard port number for outside network, like WEB server(HTTP 80). Below is the example for two public IPs and map to two different PCs at internal network.
Example:
Public IP1: 203.217.21.22
Public IP2: 203.217.21.23
WEB Server1: 192.168.1.1
WEB Server2: 192.168.1.2
For first one, you can refer the section of Virtual Server in user manual. And it can be set via WEB GUI.
For second one, you have to type CLI command as below.
Step 1:‘nat add globalpool <gp1> <ipwan> internal 203.217.21.22 subnetmask 255.255.255.252’or ‘nat add globalpool <gp1> <ipwan> internal 203.217.21.22 endaddress 203.217.21.23’
Syntax: nat add globalpool <name> <interfacename> {internal|dmz} <ipaddress> {subnetmask <mask>|endaddress <address>}
Step 2:‘nat add resvmap <rm2> globalip <ipwan> 203.217.21.23 192.168.1.2 tcp 80’
Syntax: nat add resvmap <name> globalip <interfacename> <globalip> <internalip> {tcp|udp} <portno> [<2ndportno> [<localportno> [2ndlocalportno]]]
<gp1>, <ipwan>, <rm2> are names, defined by users.
The concept is adding a global (or said public) IP pool in WAN side and let NAT module know it. Then, create another kind of Virtual Server to map it. If possible, he could use 'all' instead of 'tcp 80' at first stage to test the reach ability.