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Scenario-based practice

Troubleshooting Scenario Questions

Practise ENCOR 350-401 practice questions — original exam-style scenarios covering every exam domain, with detailed explanations, wrong-answer analysis, and common exam traps.

15
scenario questions
350-401
exam code
Cisco
vendor

Scenario guide

How to approach troubleshooting scenario questions

These questions describe a network symptom and ask you to identify the root cause or the correct fix. They appear across all certification exams and reward systematic thinking over memorisation. The best candidates follow a consistent troubleshooting framework even under time pressure.

Quick answer

Troubleshooting Scenario Questions questions test whether you can apply the concept in context, not just recognise a definition.

How the topic appears in realistic exam-style scenarios.

Which detail in the question changes the correct answer.

How to eliminate plausible but wrong options.

How to connect the question back to the wider exam objective.

Related practice questions

Related 350-401 topic practice pages

Scenario questions usually connect to one or more exam topics. Use these links to review the underlying concepts behind the scenario.

Practice set

Practice scenarios

Question 1hardmultiple choice
Study the full EIGRP explanation →

Refer to the exhibit. A network engineer is troubleshooting a routing issue. The route for 10.0.0.0/8 is learned via EIGRP with metric 2560512. Which change would most likely cause the metric to increase?

Exhibit

Refer to the exhibit.
```
router# show ip route 10.0.0.0
Routing entry for 10.0.0.0/8
  Known via "eigrp 100", distance 170, metric 2560512, type internal
  Redistributing via eigrp 100
  Last update from 192.168.1.1 on GigabitEthernet0/0, 00:00:05 ago
  Routing Descriptor Blocks:
  * 192.168.1.1, from 192.168.1.1, 00:00:05 ago, via GigabitEthernet0/0
      Route metric is 2560512, traffic share count is 1
      Total delay is 2000 microseconds, minimum bandwidth is 10000 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 1/255, Hops 3
```
Question 2easymultiple choice
Open the full VLAN trunking answer →

A network administrator is troubleshooting a performance issue in a large enterprise campus network. The network consists of Cisco Catalyst 9300 switches acting as access switches and Cisco Catalyst 9500 switches as distribution. Users on VLAN 10 report intermittent slow file transfers to a server on VLAN 20. The administrator has verified that there are no errors on the links, CPU utilization is normal, and STP topology is stable. The administrator suspects a possible QoS issue. Upon checking the QoS configuration on the access switch, the administrator finds that the default QoS configuration is in place, which trusts the CoS value at the port level. The connected devices are IP phones and PCs; the IP phones mark voice traffic with CoS 5. The server on VLAN 20 is connected to a distribution switch. Which action should the administrator take to most likely resolve the issue?

Question 3hardmultiple choice
Open the full VLAN trunking answer →

Your company has deployed a Cisco Catalyst 9300 switch stack as the distribution layer for a campus network. The network uses VLANs 10 (data), 20 (voice), and 30 (management). The switch stack is configured with DHCP snooping, Dynamic ARP Inspection (DAI), and IP Source Guard (IPSG) on access ports. Recently, users in VLAN 10 report intermittent connectivity issues. You notice that some users receive duplicate IP addresses from the DHCP server. The DHCP server is connected to a trunk port on the switch stack. After reviewing logs, you see that DHCPACK messages are being dropped on the trunk port. The DHCP snooping binding table shows entries for legitimate clients, but also some entries with MAC addresses from a different vendor. Which action should you take to resolve the issue?

Question 4mediummultiple choice
Full question →

An engineer is troubleshooting intermittent connectivity issues between two data center switches. The link is a 10GE LACP port-channel. Which misconfiguration could cause packet loss?

Question 5mediummultiple choice
Read the full VRF explanation →

A network engineer is troubleshooting connectivity issues in a multi-tenant environment where each tenant's traffic is isolated using VRF-Lite. The engineer notices that tenants in the same VRF cannot communicate with each other across different access switches. Which design change should be implemented to enable inter-switch VRF communication?

Question 6mediummultiple choice
Study the full EIGRP explanation →

A network engineer is troubleshooting an EIGRP adjacency issue between two routers. The engineer verifies that both routers have the same K-values and autonomous system number. However, the adjacency does not form. Which configuration issue is most likely the cause?

Question 7hardmultiple choice
Open the full BGP breakdown →

An engineer is troubleshooting a BGP routing issue. The router is not receiving routes from an eBGP neighbor. The neighbor is reachable via ping. The BGP session is established and in the Established state. What is the most likely cause?

Question 8hardmultiple choice
Review the full OSPF breakdown →

A network administrator is troubleshooting an issue where OSPF routes are not being learned from a neighbor. The administrator checks the OSPF configuration and sees that both routers are in the same area. The neighbor state is stuck in EXSTART. What is the most likely cause?

Question 9mediummultiple choice
Open the full VLAN trunking answer →

A network engineer is troubleshooting intermittent connectivity issues between two switches connected via a trunk link. The engineer notices that the port counters show a high number of CRC errors and runts on one side. Which action should the engineer take first?

Question 10hardmultiple choice
Open the full VLAN trunking answer →

A network administrator is troubleshooting a DHCP snooping issue on a Cisco switch. The switch is configured with DHCP snooping globally and on VLAN 10. The trusted interface is GigabitEthernet0/1 connected to the DHCP server. However, clients on VLAN 10 are not receiving IP addresses from the DHCP server. What is the most likely cause?

Question 11mediummultiple choice
Read the full MPLS explanation →

A network engineer is configuring MPLS L3VPN on a Cisco IOS-XE router. The VRF CUSTOMER_C has route-target import 300:1 and export 300:1. The PE receives VPNv4 routes from the route reflector, but the CE router connected to the PE cannot ping any remote site IP addresses. The PE can ping the remote site IP addresses from the VRF. What is the most likely cause?

Question 12easymultiple choice
Review the full OSPF breakdown →

A network engineer is troubleshooting an automated configuration change that caused a routing loop. The change was pushed via an Ansible playbook that modified OSPF cost values on multiple routers simultaneously. What is the most likely reason for the loop?

Question 13mediummultiple choice
Read the full EtherChannel explanation →

A network engineer is troubleshooting an EtherChannel between two Cisco switches. The show etherchannel 1 port-channel command shows the port-channel is up, but traffic is not load-balanced evenly. The engineer notices that all traffic is using only one link. The physical ports are all configured identically. What is the most likely cause?

Question 14mediummultiple choice
Open the full VLAN trunking answer →

An engineer is troubleshooting an EtherChannel between two switches. The show etherchannel summary output shows that the port-channel is up, but only one physical link is active. The other three links are in a suspended state. The physical ports are all configured identically with the same VLAN allowed. What is the most likely cause?

Question 15hardmultiple choice
Open the full VLAN trunking answer →

A network engineer is troubleshooting an EtherChannel between two Cisco switches. The show etherchannel summary command shows the port-channel is up, but the show interfaces trunk command shows that the trunk is not passing traffic for VLAN 100. The allowed VLAN list on the port-channel interface includes VLAN 100. What is the most likely cause?

These 350-401 practice questions are part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style 350-401 questions with detailed explanations, topic-based practice, mock exams, readiness tracking, and study analytics.