11.16 Configuring NAT Virtual Interface

CCNP RS 300-101, Establishing Internet Connectivity, Uncategorized

Consider this topology:

We’ll use dynamic NAT for the PC network and static NAT for the server. Configure the dynamic NAT ACL:

Now create a NAT pool for translation using the IP range of 209.165.201.5/27 to 209.165.201.10/27. Note the use of the prefix-length command instead of the netmask command, which provide the same result, but are configured differently.

This created the NVI.

Now the static NAT:

Note, PAT can be used here as well. There is no difference in configuration, you just don’t use ip nat inside or ip nat outside.

The NVI takes the first interface that is NAT-capable. The IP is logical and does not affect NAT functionality.

Now enable the NAT function on the interfaces:

Now watch the NVI in action as the PC tries to ping the external NAT’d address (and the real address):

Check the NAT NVI translations. Note that instead of inside and outside local/global, it says source and destination:

But the traditional show command does not show anything because the router is not configured that way:

To observe NVI statistics, issue the show ip nat nvi statistics command:

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