ZyXEL Communications ZyWALL5UTM 4.0 User Manual

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ZyWALL 5/35/70 Series User’s Guide
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Chapter 22 Network Address Translation (NAT)
The following table describes the labels in this screen.  
Table 128   NAT Address Mapping Edit 
LABEL
DESCRIPTION
Type
Choose the port mapping type from one of the following. 
1. One-to-One: One-to-One mode maps one local IP address to one global IP 
address. Note that port numbers do not change for One-to-One NAT mapping 
type.
 
2. Many-to-One: Many-to-One mode maps multiple local IP addresses to one 
global IP address. This is equivalent to SUA (i.e., PAT, port address translation), 
ZyXEL's Single User Account feature. 
 
3. Many-to-Many Overload: Many-to-Many Overload mode maps multiple local IP 
addresses to shared global IP addresses. 
 
4. Many One-to-One: Many One-to-One mode maps each local IP address to 
unique global IP addresses. 
 
5. Server: This type allows you to specify inside servers of different services 
behind the NAT to be accessible to the outside world.
Local Start IP
This is the starting Inside Local IP Address (ILA). Local IP addresses are N/A for 
Server port mapping.
Local End IP
This is the end Inside Local IP Address (ILA). If your rule is for all local IP 
addresses, then enter 0.0.0.0 as the Local Start IP address and 255.255.255.255 
as the Local End IP address. 
This field is N/A for One-to-One and Server mapping types.
Global Start IP
This is the starting Inside Global IP Address (IGA). Enter 0.0.0.0 here if you have a 
dynamic IP address from your ISP. 
Global End IP
This is the ending Inside Global IP Address (IGA). This field is N/A for One-to-
OneMany-to-One and Server mapping types.
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22.5  Port Forwarding  
A port forwarding 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 NAT 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.