ZyXEL Communications P-870HW-I User Manual

P-870HW-I1 User’s Guide

Appendix D NAT

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Figure 269   Symmetric NAT

SUA (Single User Account) is a ZyNOS implementation of a subset of NAT that supports two 
types of mapping, Many-to-One and Server. The ZyXEL Device also supports Full Feature 
NAT to map multiple global IP addresses to multiple private LAN IP addresses of clients or 
servers using mapping types.

A SUA server set is a list of inside (behind NAT on the LAN) servers, for example, web or 
FTP, that you can make visible to the outside world even though SUA makes your whole 
inside network appear as a single computer to the outside world. 

You may enter a single port number or a range of port numbers to be forwarded, and the local 
IP address of the desired server. The port number identifies a service; for example, web 
service is on port 80 and FTP on port 21. In some cases, such as for unknown services or 
where one server can support more than one service (for example both FTP and web service), 
it might be better to specify a range of port numbers. You can allocate a server IP address that 
corresponds to a port or a range of ports.

Note: Many residential broadband ISP accounts do not allow you to run any server 

processes (such as a Web or FTP server) from your location. Your ISP may 
periodically check for servers and may suspend your account if it discovers any 
active services at your location. If you are unsure, contact your ISP.