3 nat/pat – Planet Technology G.SHDSL Bridge/Router GRT-402 User Manual

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PLANET Technology Corp.

GRT-101/401/402 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 series 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 series. You

could configure GRT series 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 series 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 only

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