Configuring One-to-One NAT

One-to-One NAT maps valid external IP addresses to internal addresses hidden by NAT. This enables you to hide most of your network by using internal IP addresses. However, some machines might require access. This enables you to allow direct access when necessary.

To do this, assign a range of internal IP addresses to a range of external IP addresses of equal size. The first internal IP address corresponds to the first external IP address, the second internal IP address to the second external IP address, and so on.

For example, if an ISP has assigned IP addresses 209.19.28.16 through 209.19.28.31 with 209.19.28.16 as the NAT public address and the address range 192.168.168.1 through 192.168.168.255 is used on the LAN (WorkPort), the following table shows how the IP addresses are assigned.

 

Table 8. One-to-One NAT Example

LAN Address	WAN Address	Accessed Via
192.168.168.1	209.19.28.16	Inaccessible, NAT public IP address
192.168.168.2	209.19.28.17	209.19.28.17
192.168.168.3	209.19.28.18	209.19.28.18
[...]	[...]	[...]
192.168.168.16	209.19.28.31	209.19.28.31
192.168.168.16	No corresponding IP address	No corresponding IP address
[...]	[...]	[...]
192.168.168.16	No corresponding IP address	No corresponding IP address

To configure One-to-One NAT, complete the following steps:

1	Expand the Network tree and click One-to-One NAT. The One-to-One NAT page displays.

2	Select Enable One-to-One NAT.

3	Enter the first IP address of the internal IP address range in the Private Range Begin field.

4	Enter the first corresponding external IP address in the Public Range Begin field.

NOTE: Do not include the NAT Public IP Address in a range.

5	Enter the number of IP addresses in the range in the Range Length field.

6	Click Add Range.

7	To add additional IP address ranges, repeat Step 3 through 6 for each range. When you are finished, click Update. The settings are changed for each selected SonicWALL appliance. To clear all screen settings and start over, click Reset.