ZyXEL Communications 792H manual Example 3 Multiple Public IP Addresses With Inside Servers

Prestige 791R G.SHDSL Router

Menu	15.2 - NAT Server Setup
Rule	Start Port No. End Port No. IP Address

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1.	Default	Default	192.168.1.10
2.	0	0	0.0.0.0
3.	0	0	0.0.0.0
4.	0	0	0.0.0.0
5.	0	0	0.0.0.0
6.	0	0	0.0.0.0
7.	0	0	0.0.0.0
8.	0	0	0.0.0.0
9.	0	0	0.0.0.0
10.	0	0	0.0.0.0
11.	0	0	0.0.0.0
12.	0	0	0.0.0.0

Press ENTER to Confirm or ESC to Cancel:

Figure 27-14 NAT Example 2 - Menu 15.2.1

27.4.3 Example 3: Multiple Public IP Addresses With Inside Servers

In this example, there are 3 IGAs from our ISP. There are many departments but two have their own FTP server. All departments share the same router. The example will reserve one IGA for each department with an FTP server and all departments use the other IGA. Map the FTP servers to the first two IGAs and the other LAN traffic to the remaining IGA. Map the third IGA to an inside web server and mail server. Four rules need to be configured, two bi-directional and two uni-directional as follows.

Rule 1. Map the first IGA to the first inside FTP server for FTP traffic in both directions (1 : 1 mapping, giving both local and global IP addresses).

Rule 2. Map the second IGA to our second inside FTP server for FTP traffic in both directions (1 : 1 mapping, giving both local and global IP addresses).

Rule 3. Map the other outgoing LAN traffic to IGA3 (Many : 1 mapping).

Rule 4. You also map your third IGA to the web server and mail server on the LAN. Type Server allows you to specify multiple servers, of different types, to other computers behind NAT on the LAN.

The example situation looks somewhat like this:

27-14 NAT