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350-401 Practice Question: Configures VRF-lite on a router with the…
A network engineer configures VRF-lite on a router with the following snippet:
vrf definition GREEN rd 200:1 !
interface GigabitEthernet0/3
vrf forwarding GREEN
ip address 172.16.1.1 255.255.255.0
!
router ospf 10 vrf GREEN network 172.16.1.0 0.0.0.255 area 0
What is missing from this configuration to enable proper OSPF routing within VRF GREEN?
⚠ Common exam trap
Cisco often tests the misconception that VRF-lite requires 'route-target' commands, which are actually only necessary for MPLS VPNs, not for simple VRF-lite configurations.
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 configuration is complete and OSPF will operate correctly within VRF GREEN.
The configuration is complete for VRF-lite OSPF routing. In VRF-lite, the 'vrf definition GREEN' with an RD, the interface assignment via 'vrf forwarding GREEN', and the OSPF process with 'vrf GREEN' and the network statement are all that is required. OSPF will operate correctly within VRF GREEN using the specified network in area 0.
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 configuration is complete and OSPF will operate correctly within VRF GREEN.
Why this is correct
The configuration is complete because the 'router ospf <pid> vrf GREEN' command correctly creates an OSPF process bound to VRF GREEN, and the 'network' statement uses a wildcard mask to advertise the appropriate subnet into OSPF. The router-id is automatically selected from the highest loopback or active interface address in the VRF, so no explicit router-id is required. Thus, OSPF will operate correctly within the VRF.
- ✗
The 'network' command should specify the interface instead of the subnet.
Why it's wrong here
This is incorrect because OSPF network commands are designed to match IP addresses using a network number and wildcard mask, not interface names. The proper syntax is 'network <network> <wildcard-mask> area <area-id>', and interface-level OSPF activation would be done with 'ip ospf <pid> area <area-id>' on the interface itself. Specifying an interface in the network command would be invalid and is not supported in IOS.
- ✗
The 'vrf definition GREEN' must include a 'route-target' command.
Why it's wrong here
Route-targets are only necessary in MPLS VPN environments to control the export and import of VPNv4 routes between PE routers. In VRF-lite, which provides VRF awareness and route isolation on a single device without MPLS, route-targets are not required. The 'vrf definition GREEN' can be configured with just an address-family and interface membership, making the statement false.
- ✗
The OSPF process must be configured under the global VRF context, not using 'vrf GREEN'.
Why it's wrong here
This is mistaken because placing the OSPF process in the global context would associate it with the global routing table, not VRF GREEN. The correct method is exactly what is shown: 'router ospf <pid> vrf GREEN', which binds the OSPF instance to the VRF and allows its network statements to only match interfaces in that VRF. Therefore, the configuration correctly uses the vrf keyword.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
EIGRP: Basics and Advanced Configuration
Key term
Virtual Routing and Forwarding
Virtual Routing and Forwarding (VRF) is a technology that allows a single physical router to operate like multiple independent routers by keeping separate routing tables and forwarding decisions for each instance.
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JA
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.