Test Source NAT using Xena2544

Source NAT is typically used by internal users to access the internet; the source address is translated and thereby kept private.

Testbed Topology

We are using the testbed topology shown below to demonstrate how you can test a source’s NAT functions with bidirectional traffic, i.e. LAN-to-WAN and WAN-to-LAN.

The DUT has two interfaces, interface 37 and interface 38. The IP address of interface 37 is 37.0.0.1, and the IP address of interface 38 is 38.0.0.1.

Interface 37 is on the LAN side (incoming), and interface 38 is on the WAN side (outgoing). The source’s NAT policy is configured to replace the source IP address of the incoming traffic (LAN-to-WAN direction) with the outgoing interface address. This is exactly what a source NAT functions do.

We are going to show you how to create two streams, one for each direction, using Xena2544.

Stream Configuration Using Valyrie2544 for Source NAT Testing

1. Select two port to include into your test project. Port 0 will have IP = 37.0.0.2 connecting to DUT’s interface 37. Port 1 will have IP = 38.0.0.2 connecting to DUT’s interface 38.




2. In Selected Ports, assign Ethernet / IPv4 segment profile to both ports, and assign IP address and gateway address accordingly as shown below.

3. Click on P-0-2-0 and enter 38.0.0.1 into Public IP Address. This is because P-0-2-0 is the LAN port and is behind a NAT gateway whose IP address is 38.0.0.1 to the WAN side.

4. Use MESH test topology and choose bidirectional. This will make sure each port sends a stream to other ports. You can also use Pairs in the topology in this scenario.

5. Select the tests you want to carry out in Test Type Configuration.

6. Click Start to urn you Xena2544 test.