CCNA IP Routing Practice Question
Exhibit
RouterA# show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is 10.10.10.2 to network 0.0.0.0
S* 0.0.0.0/0 [1/0] via 10.10.10.2, GigabitEthernet0/0
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.10.10.0/30 is directly connected, GigabitEthernet0/0
L 10.10.10.1/32 is directly connected, GigabitEthernet0/0
S 10.10.20.0/24 [1/0] via 10.10.10.2, GigabitEthernet0/0
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.10.0/24 is directly connected, Vlan10
L 192.168.10.1/32 is directly connected, Vlan10A network administrator is troubleshooting a connectivity issue between two remote sites connected via a WAN link. Hosts on VLAN 10 at Site A (192.168.10.0/24) cannot ping the server at Site B (10.10.20.100). The router at Site A has a default route configured with the next-hop IP address 10.10.10.2. The administrator checks the routing table on Router A and notices that the default route is not installed. What is the most likely cause of the problem?
⚠ Common exam trap
Cisco often tests the misconception that a default route alone guarantees connectivity, when in reality the next-hop must be reachable; candidates may overlook verifying the next-hop's availability.
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 next-hop router 10.10.10.2 is unreachable.
The default route uses a next-hop IP (10.10.10.2) and will only be installed in the routing table if that next-hop is reachable. Since the router’s routing table shows no default route, the most likely cause is that the next-hop 10.10.10.2 is unreachable, preventing the static route from being used. This explains why traffic fails despite the configuration.
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 static route for 10.10.20.0/24 is missing from the routing table.
Why it's wrong here
The routing table entry for 10.10.20.0/24 is visible in the output, showing 'via 10.10.10.2', so the static route is certainly not missing. This option misreads the table; the missing entry is actually the default route (0.0.0.0/0), not the static route to the 10.10.20.0 network. The presence of this specific static route does not affect the default route's reachability, which is the real issue.
- ✗
The GigabitEthernet0/0 interface is administratively down.
Why it's wrong here
The interface status in the exhibit is 'up/up' with IP address 10.10.10.1, and the connected route for 10.10.10.0/24 is present in the routing table. An administratively down interface would be 'shutdown' and would remove all connected routes, including the subnet that contains the next-hop. Since the next-hop is unreachable despite the interface being up, the problem lies with the remote router or Layer 2 connectivity, not the local interface state.
- ✗
The default route is not configured; the gateway of last resort is missing.
Why it's wrong here
The output includes the line 'Gateway of last resort is 10.10.10.2 to network 0.0.0.0', proving that a default route is configured and the router recognizes it as the gateway of last resort. However, the default route does not appear as an 'S*' entry in the routing table because the next-hop is unreachable. This option incorrectly assumes that the configuration is missing; in reality, the route is configured but not installed.
- ✓
The next-hop router 10.10.10.2 is unreachable.
Why this is correct
A static route with a next-hop IP is only installed in the routing table when that next-hop is reachable. Since the default route is missing from the routing table, the next-hop 10.10.10.2 must be unreachable, making option D the correct diagnosis.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The next-hop router 10.10.10.2 is unreachable.Correct answer▾
Why this is correct
A static route with a next-hop IP is only installed in the routing table when that next-hop is reachable. Since the default route is missing from the routing table, the next-hop 10.10.10.2 must be unreachable, making option D the correct diagnosis.
✗The static route for 10.10.20.0/24 is missing from the routing table.Wrong answer — click to see why▾
Why this is wrong here
The routing table shows a static route to 10.10.20.0/24 via 10.10.10.2, so the route is present. The issue is not a missing route.
Why candidates choose this
Students often assume that if a ping fails, the destination network must be missing from the routing table, but here the route exists.
✗The GigabitEthernet0/0 interface is administratively down.Wrong answer — click to see why▾
Why this is wrong here
The interface is shown as directly connected with a local address, indicating it is up and operational. An administratively down interface would show 'administratively down' in the status.
Why candidates choose this
A common troubleshooting step is to check interface status, and if a student sees no obvious issue, they might incorrectly suspect the interface is down.
✗The default route is not configured; the gateway of last resort is missing.Wrong answer — click to see why▾
Why this is wrong here
The output shows 'Gateway of last resort is 10.10.10.2 to network 0.0.0.0', confirming the default route is configured.
Why candidates choose this
Students may confuse the absence of a specific route with a missing default route, but the default route is present here.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
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Related to this question
Learn chapter
OSPFv3 Single-Area Configuration for IPv6
Key term
Routing table
A routing table is a data set stored in a router or host that contains information about network paths and is used to determine where to forward data packets.
Key term
Router
A router is a networking device that connects different networks together and directs data traffic between them by choosing the best path for data to travel.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.