E10 Configuring NAT

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Back to the Material: IPv4 Network Address Translation

Video: Instructions for E10

Topology

This exercise follows E09, thus uses its working configuration.

Preparing the topology

If everything was fine earlier, there is nothing to do/change.

You might want to remove the firewall configuration (from E09), so it is allowed

Firewall and NAT might have problems, as they have an ... interesting ... relationship :)

Configuring Many-to-1 NAT

Configure the Many-to-1 NAT on R3 as shown in the topology picture.

Warning

There are multiple subnets of private IPv4 addresses coming to your NAT router!

Take them all into account in your configuration!

Investigating traffic

Verify the functionality of the NAT through show commands

1. Place an ongoing ping from the private IPv4 subnets to the public IPv4 subnet
   • preferrably to a lubuntu workstation in the public subnet
2. Actively use the show commands to verify the working of NAT for evidence of Network Address Translation on R3

Document the results into the repository.

Verify the functionality of the NAT through wireshark

1. Place an ongoing ping from the private IPv4 subnets to the public IPv4 subnet
   • preferrably to a lubuntu workstation in the public subnet
2. Use a Lubuntu Wireshark virtual machine to capture traffic on both sides of the Network Address Translation
   • You can wireshark the cables separately, but remember to save the capture and name it accordingly

Document the results into the repository.

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License

This course and its materials are written by Karo Saharinen and licenced by Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license.