|In this test scenario, a pair of Virtual Routers are connected with a Redirected Interface connection with one side of the connection performing NAT on outgoing traffic. Two additional Redirected Interface connections are configured to pass traffic and demonstrate NAT.|
Setup two Virtual Routers and three Netsmith Connections.
Right-click inside the Netsmith window and select New Router
Repeat to create another virtual router
Right-click inside the Netsmith window and select New Connection
Select the 'Skip' option on Port 1-B, WanLink and Port 2-B, then click OK
Repeat and create two more connections
Click the Apply button followed by the Sync button
NOTE: Modifications in Netsmith are only sent to the LANforge-Server after Applying them
Clicking Sync makes sure any changes are synchronized with the current database
For more information see LANforge-GUI User Guide: Virtual Interfaces
Setup the Ports.
Right-click the rdd ports and select Modify Port
Assign each pair of rdd ports a unique subnet and IP address
Select the 'IPv4s' checkbox to view the IP addresses of the rdd ports
Configure rddVR3 and rddVR5 with a Gateway IP that corresponds to their peer rdd interface
NOTE: In this example, rddVR3 has a Gateway IP of 184.108.40.206 and rddVR5 has a Gateway IP of 220.127.116.11
For more information see LANforge-GUI User Guide: Ports (Interfaces)
Move the Redirected Interfaces into their desired positions.
Drag rddVR0 into Router R0(1) and rddVR1 into Router R1(2)
Drag rddVR2 into Router R0(1) and rddVR4 into Router R1(2)
Click Netsmith Apply to commit the changes
Create a TCP connection and sniff traffic without NAT.
Go to the Layer-3 tab and click Create
Create a Layer-3 TCP connection between endpoints rddVR3 and rddVR5 then click OK
In Netsmith, right-click the TCP connection and click Start
Right-click port rddVR1 and click Sniff Port
NOTE: You must have Wireshark properly installed as described here: Installing Wireshark
After Wireshark begins, notice that the source and destination IP addresses are from 18.104.22.168 (rddVR3) and 22.214.171.124 (rddVR5) as expected without NAT enabled
Enable NAT and sniff traffic on the same port.
NOTE It is important that Endpoint-A of the connection is behind the NAT port because it is the side that initiates the connection. Reversing the endpoint ports will cause the connection to fail.
Right-click on the TCP connection and select Stop
Right-click rddVR0 and select Modify
Select the 'NAT' checkbox and click OK, then click the Netsmith Apply button
Right-click on the TCP connection and select Start
Right-click port rddVR1 and select Sniff Port
After Wireshark begins, notice that any source or destination
IP address from or to 126.96.36.199 (rddVR3) has been NAT'd to be 10.10.10.10 because rddVR0 is now performing NAT on all outgoing traffic
For more information see LANforge-GUI User Guide