PLANET Technology Corp.

GRT-101/401 User’s Manual

admin# write

3.11.3 NAT/PAT

NAT can be used to share an Internet connection, to reduce the requirement for publicly assigned IP addresses, to expand an existing network without affecting existing IP based account schemes, and to hide an internal network schema from public networks.

It is often used in the situation where only one IP address could be assigned for the network, such as a PPP connection to an local ISP, e.g., when your local ISP uses protocols of “PPPoA” or “PPPoE” over the ATM VC, you get a dynamic public IP at the WAN port from your local ISP. All requests originating from the LAN (private network) have their source IP addresses replaced with the public IP address. Only one IP address is visible from the public network. To setup this GRT-101/GRT-401 working for the above example, enter:

admin# setup lan 1 attrib Virtual

Also, make sure to delete all entries in the NAT/PAT IP pools by the following commands:

admin# setup ip_share nat virtual delete <1~5> admin# setup ip_share nat global delete <1~5> admin# setup ip_share nat fixed delete <1~128> admin# setup ip_share pat clear <1~10>

Note: The maximum number of hosts on the LAN (private network) is limited to be of 253 in dynamic NAT.

To save your changes, enter:

admin# write

In some cases, the number of externally visible IP addresses is greater than one and less than the host number being hidden behind GRT-101/GRT-401. You could configure GRT-101/GRT-401 such that it acts as follows. Each time a request is made from a host on the LAN, which is included in virtual IP pool, e.g., pool 3: 192.168.0.2~192.168.0.25. GRT-101/GRT-401 chooses an external IP address already configured in the corresponding global IP pool 3 (e.g., 69.210.1.2~69.210.1.7, which is assigned from your local ISP) that is currently unused, and then performs the translation. This type of situation is

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