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This page has 15 Router R1 Cannot Reach R3 Practice Questions scenario questions for the 350-401 exam, each with detailed explanations and wrong-answer analysis.

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Read the full scenario before looking at the answer options. Identify the constraint or requirement in the scenario, then eliminate options that are generally true but wrong for this specific case. Scenario questions reward careful reading over pattern matching.

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Scenario-based practice

Router R1 Cannot Reach R3 Practice Questions

Practise identifying common networking hardware like routers, switches, access points, and their roles in a network.

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scenario questions

350-401

exam code

Cisco

vendor

Scenario guide

How to approach router r1 cannot reach r3 practice questions

Practise routing and connectivity troubleshooting scenarios involving R1, R2, R3, static routes, OSPF, next hops and routing tables.

Quick answer

Tests identification, purpose, and configuration of routers, switches, access points, and patch panels.

Identify routers, switches, and access points by function

Understand PoE and PoE+ power requirements

Differentiate managed vs unmanaged switches

Recognize cable types: Cat5e, Cat6, fiber

Practice scenarios

Question 1mediumdrag order

Review the full OSPF breakdown →

Drag and drop the steps of OSPF summarization at ABR configuration steps into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 2mediumdrag order

Read the full DHCP explanation →

Drag and drop the steps of DHCP snooping operation on a Cisco switch into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 3mediumdrag order

Read the full DHCP explanation →

Drag and drop the steps of DHCP snooping and dynamic ARP inspection flow into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 4mediummatching

Review the full OSPF breakdown →

Drag and drop each OSPF router role on the left to its matching function on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Generates the Network LSA and maintains full adjacencies with all routers on the segment

Monitors the DR and assumes the DR role if the DR fails

Forms full adjacencies only with the DR and BDR

Connects multiple areas and advertises inter-area routes

Redistributes external routes into OSPF

Question 5mediummultiple choice

Review the full OSPF breakdown →

Given the following configuration on a Cisco IOS-XE device:

router ospf 1
 network 10.0.0.0 0.255.255.255 area 0

interface GigabitEthernet0/0
 ip address 10.1.1.1 255.255.255.0
 ip ospf cost 10

interface GigabitEthernet0/1
 ip address 10.2.2.1 255.255.255.0

Which statement is true about OSPF operation?

A
Both interfaces will have an OSPF cost of 10.
Why wrong: Incorrect. Only GigabitEthernet0/0 has the explicit cost of 10. GigabitEthernet0/1 will use the default cost based on its bandwidth (e.g., 1 for GigabitEthernet).
B
GigabitEthernet0/0 will have an OSPF cost of 10, and GigabitEthernet0/1 will have a default cost based on its bandwidth.
Correct. The explicit cost applies only to the interface it is configured on. The other interface uses the default cost.
C
Both interfaces will have the same OSPF cost because they are in the same area.
Why wrong: Incorrect. OSPF cost is interface-specific and not determined by area membership alone.
D
OSPF will not run on either interface because the network command uses a wildcard mask of 0.255.255.255.
Why wrong: Incorrect. The wildcard mask 0.255.255.255 matches all addresses starting with 10.x.x.x, so both interfaces are included.

Full breakdown with real-world context →

Question 6mediummultiple choice

Open the full BGP breakdown →

A network administrator is troubleshooting a BGP routing issue where routes from an eBGP neighbor are not being installed in the routing table. The 'show ip bgp' output shows the routes are received but not valid. What is the most likely cause?

A
The AS-path contains the local AS number.
Why wrong: This is incorrect. While an AS-path containing the local AS number can cause routes to be rejected due to loop prevention, the typical symptom is routes not being received at all or being marked as invalid, not the specific 'received but not valid' status. The most common cause for 'not valid' is next-hop unreachability.
B
The next-hop IP address is not reachable.
Correct. For a BGP route to be considered valid and installed in the routing table, the next-hop IP address must be reachable via an IGP or static route. If the next hop is not reachable, the route will appear in the 'show ip bgp' output but be marked as not valid.
C
BGP synchronization is enabled.
Why wrong: This is incorrect. BGP synchronization is a legacy feature that requires the route to be in the IGP before it is advertised. In modern networks, synchronization is disabled by default. Even if enabled, it affects advertisement, not the validity of received routes in the BGP table.
D
The maximum-prefix limit has been exceeded.
Why wrong: This is incorrect. Exceeding the maximum-prefix limit typically causes the BGP session to reset or routes to be withdrawn, not to be marked as 'not valid' in the BGP table. Routes would likely be removed entirely, not just marked invalid.

Full breakdown with real-world context →

Question 7mediumdrag order

Full question →

Drag and drop the steps of NBAR2 application recognition and classification steps into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 8mediumdrag order

Review the full OSPF breakdown →

Drag and drop the steps of OSPF neighbor adjacency formation into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 9hardmultiple choice

Review the full routing breakdown →

A network engineer runs the following command on Router R1:

R1# show ip access-lists

Extended IP access list 150

10 permit tcp 10.0.0.0 0.255.255.255 any eq 23 (2 matches)
    
20 deny tcp any any eq 23 (8 matches)
    
30 permit tcp 172.16.0.0 0.0.255.255 any eq 22 (4 matches)
    
40 deny tcp any any eq 22 (1 match)
    
50 permit ip any any (15 matches)

Based on this output, what can be concluded?

A
Telnet from 192.168.1.0/24 would be denied, and SSH from 10.0.0.0/8 would be denied.
Telnet from 192.168.1.0/24 matches entry 20 (deny), and SSH from 10.0.0.0/8 does not match entry 30 (which permits only from 172.16.0.0/16), so it matches entry 40 (deny).
B
Telnet from 10.0.0.0/8 is denied.
Why wrong: Entry 10 permits Telnet from 10.0.0.0/8.
C
SSH from 172.16.0.0/16 is denied.
Why wrong: Entry 30 permits SSH from 172.16.0.0/16.
D
All traffic is permitted.
Why wrong: Telnet and SSH from unauthorized sources are denied.

Full breakdown with real-world context →

Question 10mediumdrag order

Review the full OSPF breakdown →

Drag and drop the steps of OSPF SPF calculation steps (Dijkstra) into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 11mediumdrag order

Full question →

Drag and drop the steps of traffic shaping vs policing configuration steps into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 12mediummulti select

Review the full OSPF breakdown →

Which two statements about OSPF network types are true? (Choose two.)

A
On a broadcast multiaccess network, OSPF elects a DR and BDR to reduce LSA flooding.
Correct because on broadcast networks (e.g., Ethernet), a Designated Router (DR) and Backup DR are elected to minimize the number of adjacencies and flooding.
B
The OSPF point-to-point network type requires a DR/BDR election.
Why wrong: Incorrect because point-to-point networks do not use DR/BDR; they form a single adjacency between the two routers.
C
On a non-broadcast multiaccess (NBMA) network, OSPF can use the neighbor command to manually discover neighbors.
Correct because NBMA networks (e.g., Frame Relay) require manual neighbor configuration since they lack broadcast capability.
D
The OSPF point-to-multipoint network type always elects a DR.
Why wrong: Incorrect because point-to-multipoint networks treat each link as a point-to-point link and do not use DR/BDR.
E
The default OSPF network type for a loopback interface is point-to-point.
Why wrong: Incorrect because the default network type for a loopback interface is 'loopback', which is a special type that always advertises the interface as a /32 host route.

Full breakdown with real-world context →

Question 13mediumdrag order

Review the full OSPF breakdown →

Drag and drop the steps of EIGRP redistribution from OSPF with metric seeding into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 14mediummulti select

Study the full multicast explanation →

Which two statements about IGMP snooping are true? (Choose two.)

A
IGMP snooping reduces unnecessary multicast flooding on a Layer 2 switch.
Correct because IGMP snooping allows the switch to forward multicast frames only to ports that have joined the group, reducing flooding.
B
IGMP snooping uses the IGMP querier election process to select the switch with the highest IP address as the querier.
Why wrong: Incorrect because the IGMP querier is elected based on the lowest IP address, not the highest.
C
IGMP snooping can be configured to replace IGMP on the router interface.
Why wrong: Incorrect because IGMP snooping is a Layer 2 feature that works alongside IGMP; it does not replace the IGMP protocol on routers.
D
IGMP snooping listens to IGMP membership reports and leave messages to build a forwarding table.
Correct because the switch examines IGMP messages to learn which ports have joined or left a multicast group.
E
IGMP snooping modifies the IP header of multicast packets to include group membership information.
Why wrong: Incorrect because IGMP snooping does not modify packets; it only inspects IGMP control messages to update its forwarding database.

Full breakdown with real-world context →

Question 15mediumdrag order

Review the full OSPF breakdown →

Drag and drop the steps of OSPF redistribution from EIGRP with metric conversion into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

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.

Router R1 Cannot Reach R3 Practice Questions

How to approach router r1 cannot reach r3 practice questions

Quick answer

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Practice scenarios

Drag and drop the steps of OSPF summarization at ABR configuration steps into the correct order, from first to last.

Drag and drop the steps of DHCP snooping operation on a Cisco switch into the correct order, from first to last.

Drag and drop the steps of DHCP snooping and dynamic ARP inspection flow into the correct order, from first to last.

Drag and drop each OSPF router role on the left to its matching function on the right.

A network administrator is troubleshooting a BGP routing issue where routes from an eBGP neighbor are not being installed in the routing table. The 'show ip bgp' output shows the routes are received but not valid. What is the most likely cause?

Drag and drop the steps of NBAR2 application recognition and classification steps into the correct order, from first to last.

Drag and drop the steps of OSPF neighbor adjacency formation into the correct order, from first to last.

Drag and drop the steps of OSPF SPF calculation steps (Dijkstra) into the correct order, from first to last.

Drag and drop the steps of traffic shaping vs policing configuration steps into the correct order, from first to last.

Which two statements about OSPF network types are true? (Choose two.)

Drag and drop the steps of EIGRP redistribution from OSPF with metric seeding into the correct order, from first to last.

Which two statements about IGMP snooping are true? (Choose two.)

Drag and drop the steps of OSPF redistribution from EIGRP with metric conversion into the correct order, from first to last.