From CCIE Study Wiki
NAT Virtual Interfaces or (NVI) can help simplify what would otherwise be complex NAT configurations
Theory
The NAT Virtual Interface (NVI) feature removes the requirement to configure an interface as either NAT inside or NAT outside. An interface can simply be configured to use NAT or to not use NAT.
When a NAT pool is shared for translating packets from multiple networks connected to a NAT router, an NVI is created and a static route is configured that forwards all packets addressed to the NAT pool to the NVI. The standard interfaces connected to the various networks need to be configured to identify that the traffic coming to/from these interfaces needs to be translated.
Commands
- ip nat enable (interface) - configures an interface for NAT using a NVI
- ip nat source list acl pool name vrf name [overload] - Defines source IP's , NAT pool, and VRF instance are associated with the dynamic NVI.
- ip nat source static local-ip global-ip vrf name (global) - sets up a static NVI
Default Settings
Verification
Troubleshooting, Tips, and Tricks
- When using a NAT virtual interface, route maps are not supported.
Online Resources
- Configuring the NAT virtual interface feature from the Cisco IOS IP addressing services configuration guide.
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