350-401 Virtualization Practice Question
A network administrator is enabling a virtual routing and forwarding instance on a Cisco IOS-XE router to separate customer traffic. The administrator issues the ip vrf forwarding CUSTOMER_A command on Gi0/0/1, and the interface immediately loses its IP address. What is the reason for this behavior?
⚠ Common exam trap
The trap here is treating the disappearance of the IP address as a fault or a sign of a missing VRF, rather than as expected behavior when moving an interface between routing tables.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Assigning an interface to a VRF removes any previously configured IP address
On Cisco IOS-XE, entering the ip vrf forwarding command on an interface moves that interface into the named VRF and removes any IP address previously configured in the global table. The address must be reapplied afterward so the interface participates in the VRF's routing and forwarding tables. This is normal, expected behavior.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The router reloaded and lost the running configuration
Why it's wrong here
A reload would affect the entire device and all interfaces, not just the one being assigned to a VRF. The scenario describes an immediate change triggered by the ip vrf forwarding command, which is the documented cause of IP address removal, so a reload is not a plausible explanation here.
- ✗
The interface entered a shutdown state due to the VRF assignment
Why it's wrong here
Assigning an interface to a VRF does not administratively shut it down. The interface remains in its prior state, and the address removal is a separate configuration consequence of moving the interface between routing tables, so a shutdown state is not the reason the address disappeared.
- ✓
Assigning an interface to a VRF removes any previously configured IP address
Why this is correct
When an interface is moved into a VRF, Cisco IOS-XE removes its existing IP address because the address belonged to the global routing table. The administrator must re-enter the IP address after the VRF assignment so the interface has an address within the VRF's own address space. This is expected behavior, not a fault.
- ✗
The VRF was not yet created in global configuration mode
Why it's wrong here
If the VRF did not exist, IOS-XE would create it automatically when the interface command is entered, so a missing VRF definition is not the cause. The address loss is a documented behavior of assigning an interface to a VRF, not a symptom of a missing VRF definition in the configuration.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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