ZyXEL Communications P-861H-G1, User Manual, Page: 89 / 341

Prestige 861H Series User’s Guide
Chapter 6 Network Address Translation (NAT) Screens 88
6.2 SUA (Single User Account) Versus 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 Prestige also supports Full Feature NAT
to map multiple global IP addresses to multiple private LAN IP addresses of clients or servers
using mapping types as outlined in
Table 16 on page 87 .
• Choose SUA Only if you have just one public WAN IP address for your Prestige.
• Choose Full Feature if you have multiple public WAN IP addresses for your Prestige.
6.3 SUA Server
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.
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, refer to your ISP.
6.3.1 Default Server IP Address
In addition to the servers for specified services, NAT supports a default server IP address. A
default server receives packets from ports that are not specified in this screen.
If you do not assign an IP address in Server Set 1 (default server) the Prestige discards all
packets received for ports that are not specified here or in the remote management setup.
6.3.2 Port Forwarding: Services and Port Numbers
The most often used port numbers are shown in the following table. Please refer to RFC 1700
for further information about port numbers.
Table 17 Services and Port Numbers
SERVICES PORT NUMBER
ECHO 7
FTP (File Transfer Protocol) 21