CalAmp Viper 100 User Manual page 56

The purpose of the NAT protocol is to hide a private IP network from a public network. This mechanism serves first as a
firewall and second to save IP address space.
The NAT enabled device translates the source address of packets transiting from the private network to the public network.
The original IP source address gets replaced by the NAT enabled IP address (address of the outgoing interface). The NAT
module creates an address translation table that is used when traffic is coming back from the public network to the private
network.
The user can select which of two interfaces (Ethernet or RF) will be considered private. The following examples illustrate
how to configure the Viper SCs. The examples use a private network of 192.168.205.X and a public network of 172.31.5.X.
4.4.2.2.1.1 ETHERNET INTERFACE PRIVATE
Figure 31 shows NAT enabled for the Ethernet interface.
Figure 31 – NAT enabled, Ethernet (Private)
Figure 32 shows a configuration protecting Viper (1) Ethernet interface IP address from hosts located on a public network.
Figure 32 – NAT Enabled, Ethernet Interface (Private)
An IP packet whose source IP address originates from the Ethernet network and is sent towards the RF network, will have
its source IP address replaced by the RF IP address of Viper SC(1) as shown in Figure 33.
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