mediumMultiple Choice
350-401 Practice Question: Runs the following command on Router R7: R7# show…
A network engineer runs the following command on Router R7:
R7# show vrf brief
Name Default RD Protocols Interfaces Mgmt-intf <not set> ipv4,ipv6 GigabitEthernet0/0 CUSTOMER-A 65001:100 ipv4 GigabitEthernet0/1.10 CUSTOMER-B 65001:200 ipv4 GigabitEthernet0/1.20
Based on this output, what can be concluded?
⚠ Common exam trap
Cisco often tests the ability to read the 'show vrf brief' output accurately, and the trap here is that candidates may assume all VRFs have an RD set or that the Protocols column implies IPv6 support without checking the specific entry.
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
✓
VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20.
The 'show vrf brief' output explicitly lists GigabitEthernet0/1.20 under the Interfaces column for VRF CUSTOMER-B, confirming that this subinterface is associated with that VRF. VRFs use subinterfaces to segment traffic for different customers or tenants on the same physical link, and the output directly shows this mapping.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
VRF CUSTOMER-A is using IPv6.
Why it's wrong here
The protocols column for CUSTOMER-A lists only "ipv4" and contains no "ipv6" entry. IPv6 would appear as a separate protocol line if the VRF were configured with an IPv6 address family. Therefore, the claim that VRF CUSTOMER-A is using IPv6 is contradicted by the verified output.
- ✗
VRF Mgmt-intf has a route distinguisher set.
Why it's wrong here
The VRF Mgmt-intf shows its Default RD as "<not set>", meaning no route distinguisher has been configured for this VRF. An RD must be explicitly assigned with the rd command under the VRF configuration, and without one the statement that a route distinguisher is set is factually wrong.
- ✓
VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20.
Why this is correct
VRF CUSTOMER-B is correctly associated with subinterface GigabitEthernet0/1.20, as shown in the Interface column of the output. This association is made by applying the command "ip vrf forwarding CUSTOMER-B" on that subinterface, which binds the subinterface's traffic to the CUSTOMER-B VRF routing table. Therefore, this is the correct option.
- ✗
All VRFs are using the same route distinguisher.
Why it's wrong here
The output clearly indicates that each VRF has a different route distinguisher value: CUSTOMER-A and CUSTOMER-B each have unique RDs, while Mgmt-intf has no RD set (shown as "<not set>"). Because the RDs are not identical across all VRFs, the statement that all VRFs use the same route distinguisher is incorrect.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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