ZyXEL Communications Broadband Security Gateway P-312 - Manual (Page 84)

P312 Broadband Security Gateway
NAT 6-11
Field Description Option/Example
examples. and Server
Local IP Only local IP fields are N/A for server;
Global IP fields MUST be set for
Server.
Start This is the starting local IP address (ILA). 0.0.0.0
End This is the ending local IP address (ILA). If
the rule is for all local IPs, then put the Start
IP as 0.0.0.0 and the End IP as
255.255.255.255. This field is N/A for One-
to-One and Server types. 255.255.255.255
Global IP
Start This is the starting global IP address (IGA).
If you have a dynamic IP, enter 0.0.0.0 as
the Global IP Start. Note that Global IP
Start can be set to 0.0.0.0 only if the types
are Many-to-One or Server. 0.0.0.0
End This is the ending global IP address (IGA).
This field is N/A for One-to-One, Many-to-
One and Server types. 172.16.23.55
Note: For all Local and Global IPs, the End IP address must begin after the IP Start
address, i.e., you cannot have an End IP address beginning before the Start IP
address.
6.3 NAT Server Sets
A NAT server set is a list of inside servers (behind NAT on the LAN) that you can make visible to the
outside world. Menu 15.2 – NAT Server Sets is used to configure these servers. If you’re using Ethernet
Encapsulation with either RR-Manager or RR-Toshiba Service Type port 12 set to 1025 (non-editable)
as displayed in Figure 6-11.
6.3.1 Multiple Servers behind NAT
If you wish, you can make inside servers for different services, e.g., web or FTP, visible to the outside
users, even though NAT makes your whole inside network appear as a single machine to the outside world.
A service is identified by the port number, e.g., web service is on port 80 and FTP on port 21.
As an example (see the following figure), if you have a web server at 192.168.1.36 and an FTP server
192.168.1.33, then you need to specify for port 80 (web) the server at IP address 192.168.1.36 and for port
21 (FTP) another at IP address 192.168.1.33.
Please note that a server can support more than one service, e.g., a server can provide both FTP and DNS
service, while another provides only web service.