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350-401 Practice Question: Examine the following configuration snippet on a…
Examine the following configuration snippet on a Cisco IOS-XE router:
interface GigabitEthernet0/1 ip vrf forwarding BLUE ip address 192.168.1.1 255.255.255.0 no shutdown
What is the effect of this configuration?
⚠ Common exam trap
Candidates may incorrectly think that the 'ip vrf forwarding BLUE' command on an interface creates the VRF automatically. In Cisco IOS-XE, the VRF must first be defined using 'vrf definition BLUE' before the interface can be associated with it. If the VRF does not exist, the command will be rejected.
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
✓
The interface is placed into VRF BLUE, and all traffic sent or received on this interface uses the routing table of VRF BLUE.
The 'ip vrf forwarding BLUE' command associates the interface with VRF BLUE, which creates a separate routing table instance. All traffic entering or exiting this interface is forwarded using the VRF BLUE routing table, not the global routing table. This isolates the interface's traffic from the global routing domain.
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 interface is placed into VRF BLUE, and all traffic sent or received on this interface uses the routing table of VRF BLUE.
Why this is correct
Configuring 'vrf forwarding BLUE' on an interface assigns that interface to VRF BLUE, removing it from the global routing context. Any IPv4 or IPv6 address subsequently configured on the interface is installed in VRF BLUE's separate routing and forwarding tables. As a result, all traffic transiting the interface is looked up exclusively in the VRF BLUE table, providing complete path isolation from the global table.
- ✗
The interface remains in the global routing table but is allowed to communicate with VRF BLUE via route leaking.
Why it's wrong here
This answer incorrectly assumes the interface stays in the global routing table while using route leaking to reach VRF BLUE. The 'vrf forwarding BLUE' command explicitly moves the interface into the VRF, so it no longer participates in the global table; route leaking would require additional static routes or address-family import/export commands to exchange routes, which is a separate mechanism and not what the command performs.
- ✗
The interface is placed into VRF BLUE, but the IP address is assigned from the global routing table.
Why it's wrong here
This answer misrepresents how IP addressing works in a VRF context. When an interface is placed into VRF BLUE, the IP address configured after that command is part of the VRF's address space and is installed only in VRF BLUE's routing table. There is no concept of borrowing an address from the global table while the interface is in a VRF; the global table retains its own independent addresses for other interfaces.
- ✗
The configuration is invalid because VRF BLUE must be created first using 'vrf definition BLUE'.
Why it's wrong here
This answer is incorrect because the interface command is valid as long as VRF BLUE has already been defined globally. The snippet shows only interface configuration, but a complete configuration would include 'vrf definition BLUE' or 'ip vrf BLUE' earlier; the absence of that in the snippet does not make the interface command invalid. Also, the command syntax is valid even if the VRF exists; no special prerequisite beyond creation is required.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.