Network Address Translation (Nat); Gateway Mode; Router Mode - DPS Telecom NetGuardian 216T User Manual

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2.4.1.1

Network Address Translation (NAT)

2.4.1.1.1 Gateway Mode

Gateway mode tells the NetGuardian to automatically pass all inbound Ethernet traffic not destined for an IP
address on the Ethernet subnet to the T1 WAN channel. Similarly, inbound IP packets encapsulated within
Frame Relay on the T1 WAN channel are forwarded out the Ethernet Hub*.
To enable Gateway mode of operation, all entries in the Static Network Address Translation (NAT) table must
have the "Enable" box left unchecked. Addresses are not translated in Gateway mode.
*Exception: IP packets will not forward to the Hub if the destination address is the NetGuardian's Ethernet
address.
Fig. 2.4.1.1.1. Configuration for Ethernet gateway traffic

2.4.1.1.2 Router Mode

The wide area network (WAN) connects two separate, private networks, allowing for mutual communication.
Before this can happen, the IP address of the local computer must be translated so that it will be recognized and
passed through to another network. This is where Network Address Translation (NAT) is used. NAT translates
the IP address for traffic coming into and leaving the local network.
From the Web browser T1 WAN menu, you can configure network computers for NAT translation in the Static
Network Address Translation fields. Be sure to select (check) the "Enable" column box.
Note: The submask number must be the same for the first three octets, which are followed by the computer's ID
number. If your submask number is outside the subnet range, use the gateway address to route the connection.
Figure 2.4.1.1 shows an example of NAT enabling for several network computers.