CCNA IP Routing Practice Test 21 — 15 Questions

Question 1

You are connected to R1. Configure R1 so that it uses a floating static route to reach the 203.0.113.0/24 network via R2 only when the primary route (learned via EIGRP) fails. The primary route has an administrative distance of 90. Currently, R1 has no route to 203.0.113.0/24 because EIGRP is down on the direct link. Ensure the floating static route is installed and used.

Accepted Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.2 95. The issue is that R1 has no route to 203.0.113.0/24 because EIGRP is not working (likely due to misconfiguration or link failure). A floating static route with an administrative distance greater than EIGRP's default AD of 90 is needed. By configuring a static route to 203.0.113.0/24 via next-hop 10.0.0.2 with AD 95, the static route will be used only when EIGRP is down (since 95 > 90, EIGRP is preferred when active). The command 'ip route 203.0.113.0 255.255.255.0 10.0.0.2 95' accomplishes this.

Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.2 90

Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.2 85

Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.2

Question 2

You are connected to R1 via the console. The network currently uses EIGRP as its IGP, but you recently configured a static default route toward R2 (next-hop 203.0.113.2) to reach the Internet. However, traffic from R1 to the Internet is not taking the expected path. Examine the provided routing table and partial configuration, then fix the issue so that the static default route is used only when the EIGRP-learned default route is unavailable.

Accepted Answer

Configure the static route with an administrative distance of 100 using 'ip route 0.0.0.0 0.0.0.0 203.0.113.2 100'.. The static default route was configured with an administrative distance (AD) of 10, which is lower than the EIGRP‑learned default route's AD of 90. This made the static route the preferred path, overriding the intended primary EIGRP route. To create a floating static route that only activates when the EIGRP route disappears, the static AD must be raised above 90—using 'ip route 0.0.0.0 0.0.0.0 203.0.113.2 100' ensures the EIGRP route is primary. Option B is wrong because removing the EIGRP route eliminates the preferred path entirely, defeating the backup purpose. Option C fails because EIGRP metrics are irrelevant against a lower‑AD static route; AD dictates route source preference. Option D is incorrect because static routes do not accept a metric parameter—the trailing number sets the AD, not a metric.

Answer

Remove the EIGRP default route by configuring 'no network 0.0.0.0' under the EIGRP process.

Answer

Increase the metric of the EIGRP default route to make it less preferred than the static route.

Answer

Configure the static route with a next-hop of 203.0.113.2 and a metric of 100.

Question 3

You are connected to R1. The network currently uses a static default route pointing to ISP1 (198.51.100.1) via GigabitEthernet0/0. However, the backup link to ISP2 (203.0.113.1) via Serial0/0/0 has a floating static default route with an administrative distance of 130. The backup route is not taking over when the primary link fails. Configure the floating static route correctly so that it becomes active when the primary route is lost, and verify that the routing table shows the backup default route with the appropriate next-hop.

Accepted Answer

Remove the primary static route and reconfigure it without the 'permanent' keyword, then verify the backup route appears in the routing table.. The primary static default route was configured with the 'permanent' keyword, which keeps the route in the routing table even when the GigabitEthernet0/0 interface goes down. This prevents the floating static route (AD 130) from becoming active. The solution is to remove the primary route (no ip route 0.0.0.0 0.0.0.0 198.51.100.1 permanent) and reconfigure it without the 'permanent' keyword. After that, when the primary link fails, the route is removed, and the backup route (AD 130) enters the routing table. Option A is correct. Option B would make the backup preferred over the primary, which is not the intended behavior. Option C (adding permanent to the backup) would not help and could cause issues. Option D (track) is an alternative but not the required configuration here.

Answer

Change the administrative distance of the floating static route to 1 so it is preferred over the primary route.

Answer

Add the 'permanent' keyword to the floating static route to ensure it remains in the routing table.

Answer

Configure a static route with a next-hop of 203.0.113.1 and an administrative distance of 130, but also add the 'track' command to monitor the primary link.

Question 4

You are troubleshooting a network connectivity issue on R1. The network 192.168.10.0/24 behind R2 must be reachable from R1 via the primary path through R2 (192.0.2.2). A backup path via R3 (198.51.100.2) should automatically take over if the primary fails. Currently, traffic to 192.168.10.0/24 is incorrectly using the backup path even though the primary path is operational. Analyze the routing table and configuration, then fix the issue so that the primary path is preferred when available.

Accepted Answer

Remove the static route to 192.168.10.0/24 via 198.51.100.2 and add a floating static route via 198.51.100.2 with AD 200. Ensure the primary route via 192.0.2.2 uses default AD 1.. The routing table shows a static route to 192.168.10.0/24 via 198.51.100.2 with Administrative Distance (AD) 1, which is the default for static routes. The intended primary path via 192.0.2.2 was configured with AD 200 (floating static), but because the default AD (1) is lower than 200, the backup route is preferred. The fix is to reconfigure the primary path with the default AD (1) and the backup path with a higher AD (e.g., 200). This ensures the primary path is used when available and the backup takes over only if the primary fails.

Answer

Change the AD of the static route via 192.0.2.2 to 200 and the AD of the route via 198.51.100.2 to 1.

Answer

Add a static route to 192.168.10.0/24 via 192.0.2.2 with AD 1 and remove the existing route via 198.51.100.2.

Answer

Configure a policy-based route to prefer the next-hop 192.0.2.2 for traffic to 192.168.10.0/24.

Question 5

You are troubleshooting connectivity from R1 to the 172.16.20.0/24 network. The network engineer configured a floating static route on R1 as a backup for the OSPF-learned route, but after the primary OSPF route fails, the backup does not take over. Examine the current routing table and partial configuration on R1, then fix the issue so that when the OSPF neighbor goes down, R1 can still reach 172.16.20.0/24 via R3.

Accepted Answer

Change the static route to use an exit interface: ip route 172.16.20.0 255.255.255.0 GigabitEthernet0/1 203.0.113.2. The floating static route was configured with an administrative distance of 130, intended to be higher than OSPF's default AD of 110 so it would only be used as a backup. However, the static route's AD is set as 130 (the command uses the distance option), which is correct. The problem is that OSPF's AD is 110, which is lower, so the static route is not installed while OSPF is up. But when OSPF fails, the static route should appear. The issue is that the static route is pointing to a next-hop (203.0.113.2) that is not directly connected; R1 has no route to 203.0.113.2, causing the static route to be inactive. To fix, you must either change the next-hop to a directly connected interface (e.g., GigabitEthernet0/1) or add a route to reach 203.0.113.2. The simplest solution is to configure the static route with an exit interface: 'ip route 172.16.20.0 255.255.255.0 GigabitEthernet0/1 203.0.113.2'. This ensures the route is valid when the OSPF route disappears.

Answer

Change the administrative distance of the static route to 110

Answer

Remove the OSPF process from R1

Answer

Add a static route to 203.0.113.0/24 via R1's directly connected interface

Question 6

You are connected to R1 via console. R1 has two upstream paths to the Internet: a primary via ISP1 (G0/0 10.1.1.1/30) and a backup via ISP2 (G0/1 10.2.2.1/30). The backup path should only be used when the primary fails. The default route to ISP1 has been configured, but you must now configure a floating static default route to ISP2 with an administrative distance of 200.

Accepted Answer

ip route 0.0.0.0 0.0.0.0 10.2.2.2 200. A floating static route ensures backup connectivity by using an administrative distance (AD) higher than the primary route's AD. Here, the primary default route has an AD of 1, so the backup must be configured with AD 200 as specified. Crucially, the next-hop address must be the ISP's IP address (10.2.2.2) in the /30 subnet, not R1's own interface IP (10.2.2.1). Using the local interface IP creates an invalid static route. Option A is correct only with the next-hop set to 10.2.2.2. Options B and C fail because they use AD 2 and 1 respectively (not the required 200) and also point to the wrong next-hop. Option D uses AD 250 instead of 200 and has the same next-hop error.

Answer

ip route 0.0.0.0 0.0.0.0 10.2.2.1 2

Answer

ip route 0.0.0.0 0.0.0.0 10.2.2.1 1

Answer

ip route 0.0.0.0 0.0.0.0 10.2.2.1 250

Question 7

You are connected to R1 via console. R1 is connected to three routers (R2, R3, R4) over Ethernet links, all in OSPF area 0. Due to network topology, R1 should not become the Designated Router (DR) or Backup Designated Router (BDR) on any of its interfaces. You need to configure R1's OSPF priority appropriately to ensure it never participates in DR/BDR elections.

Accepted Answer

Set the OSPF priority to 0 on all interfaces of R1.. Setting the OSPF priority to 0 on each Ethernet interface excludes R1 from DR/BDR elections entirely, as a priority of 0 signals that the router is ineligible. In contrast, option B (priority 255) is incorrect because the highest priority makes a router the most likely to become DR/BDR, not prevent it. Option C (priority 1) allows the router to participate in elections and could still become DR/BDR if no higher-priority router exists. Option D is wrong because setting priority to 0 on the loopback interface does not affect the physical Ethernet interfaces where elections occur.

Answer

Set the OSPF priority to 255 on all interfaces of R1.

Answer

Set the OSPF priority to 1 on all interfaces of R1.

Answer

Set the OSPF priority to 0 on the loopback interface of R1.

Question 8

You are connected to R1 via console. R1 and R2 are configured with EIGRP AS 100. R1's loopback0 (1.1.1.1/32) should be advertised into EIGRP. However, after configuration, R2 does not have a route to 1.1.1.1/32. You need to verify the EIGRP configuration on R1 and R2 to determine why the route is missing. Use show commands to identify the issue.

Accepted Answer

Use 'show ip eigrp interfaces' on R1 to verify that EIGRP is enabled on the interface facing R2 and that it is not passive.. The root cause is that R1's interface facing R2 is passive, preventing EIGRP neighbor adjacency. 'show ip eigrp interfaces' verifies the passive state, identifying why no routes are exchanged. Option B is incorrect because the local topology table may contain the route, but without an active neighbor, it will not be advertised; the topology check alone is insufficient. Option C is incorrect because the routing table may also show the locally connected route, but that does not explain why R2 lacks it. Option D is incorrect because checking R2's EIGRP configuration does not reveal R1's passive interface, which is the actual problem.

Answer

Use 'show ip eigrp topology' on R1 to confirm that the 1.1.1.1/32 route is in the EIGRP topology table.

Answer

Use 'show ip route eigrp' on R1 to verify that the 1.1.1.1/32 route is in the routing table.

Answer

Use 'show ip protocols' on R2 to verify that EIGRP AS 100 is configured and that the network statement includes the subnet of the interface facing R1.

Question 9

You are connected to R1 via console. R1 is a new router connecting two subnets: 192.168.1.0/24 on G0/0 and 192.168.2.0/24 on G0/1. You need to configure IPv6 static routes so that hosts on these subnets can reach the IPv6 Internet via R2 (2001:db8:1::2). R1's G0/0 has IPv6 address 2001:db8:1::1/64, and R2 is the next-hop. Also configure a default IPv6 route toward R2.

Accepted Answer

ipv6 route ::/0 2001:db8:1::2. A default IPv6 static route with prefix ::/0 points to the next-hop 2001:db8:1::2, which correctly forwards all traffic not in the local routing table to R2 for Internet reachability. Option B is wrong because it creates a static route for the directly connected network 2001:db8:1::/64, which is already in the routing table and unnecessary. Option C fails because on Ethernet interfaces, a static route must specify a next-hop IP address, not just an exit interface. Option D is incorrect because it creates a host route to 2001:db8:1::2, which is a directly connected address, and does not provide a default route.

Answer

ipv6 route 2001:db8:1::/64 2001:db8:1::2

Answer

ipv6 route ::/0 g0/0

Answer

ipv6 route 2001:db8:1::2/128 g0/0

Question 10

You are connected to R1 via the console. R1 is a newly deployed router that connects two subnets: 192.168.1.0/24 on GigabitEthernet0/0 and 192.168.2.0/24 on GigabitEthernet0/1. There is a default route to the Internet via ISP router at 203.0.113.1, but the network policy requires that traffic from 192.168.1.0/24 to the Internet must exit via a different next-hop 203.0.113.2. You need to implement policy-based routing on R1 to forward traffic from source 192.168.1.0/24 to 203.0.113.2, while all other traffic uses the default route via 203.0.113.1.

Accepted Answer

Create an access list matching source 192.168.1.0/24, a route-map with set ip next-hop 203.0.113.2, and apply the route-map inbound on GigabitEthernet0/0.. Policy-based routing (PBR) allows overriding the routing table for specific traffic. The access list identifies traffic from 192.168.1.0/24, the route-map sets the next-hop to 203.0.113.2, and applying it to the incoming interface G0/0 ensures that traffic entering from that subnet follows the policy.

Answer

Create an access list matching source 192.168.1.0/24, a route-map with set ip next-hop 203.0.113.2, and apply the route-map outbound on GigabitEthernet0/1.

Answer

Create an access list matching destination 203.0.113.2, a route-map with set ip next-hop 203.0.113.2, and apply the route-map inbound on GigabitEthernet0/0.

Answer

Configure a static route for 192.168.1.0/24 with next-hop 203.0.113.2 and rely on the default route for other traffic.

Question 11

You are connected to R1 via console. R1 connects three subnets: 10.0.1.0/24 (area 0), 10.0.2.0/24 (area 0), and 10.0.3.0/24 (area 0). The serial link to R2 uses IP subnet 10.0.0.0/30 and is in OSPF area 1. The network administrator wants to advertise a single summary route for these three subnets to R2, reducing the OSPF link-state database size in area 1. R1 is already running OSPF with network statements for its connected subnets in their respective areas. You need to configure route summarization on R1 so that only the summary route is advertised to R2 via the serial link.

Accepted Answer

router ospf 1
 area 0 range 10.0.0.0 255.255.252.0. The 'area 0 range' command creates a summary route for the specified range, which is then advertised as a type 3 summary LSA to other areas. This reduces routing table size and prevents flapping.

Answer

router ospf 1
 summary-address 10.0.0.0 255.255.252.0

Answer

interface serial 0/0/0
 ip summary-address ospf 1 10.0.0.0 255.255.252.0

Answer

router ospf 1
 area 0 range 10.0.0.0 255.255.255.0

Question 12

You are connected to R1 via console. R1 is a router that has two paths to the Internet: one via ISP1 with next-hop 203.0.113.1, and a backup via ISP2 with next-hop 203.0.113.2. The primary path should be via ISP1, but if it fails, traffic should automatically use ISP2. Currently, R1 has a static default route to ISP1 only. You need to configure a floating static route to ISP2 with an administrative distance of 150 to provide backup connectivity. Additionally, you must ensure that the backup route is only used when the primary route is not available.

Accepted Answer

ip route 0.0.0.0 0.0.0.0 203.0.113.2 150. By setting the administrative distance to 150, the backup static route is less preferred than the primary static route (distance 1). If the primary route is removed due to a failure, the floating route is installed, providing backup connectivity.

Answer

ip route 0.0.0.0 0.0.0.0 203.0.113.2 1

Answer

ip route 0.0.0.0 0.0.0.0 203.0.113.2 250

Answer

ip route 0.0.0.0 0.0.0.0 203.0.113.2

Question 13

You are connected to R1 via console. R1 is connected to R2 via GigabitEthernet0/0 (10.0.0.1/30) and to R3 via GigabitEthernet0/1 (10.0.0.5/30). R1 has a management subnet 192.168.1.0/24 connected to GigabitEthernet0/2. The network administrator wants to ensure that traffic from the management subnet to the Internet (203.0.113.0/24) uses R2 as the primary path and R3 as a backup. Currently, OSPF is running with default metrics. You must configure a floating static route that will be used only if the OSPF route fails.

Accepted Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.6 150. The floating static route is configured with an administrative distance of 150, which is higher than OSPF's default AD of 110. This ensures that the static route is only installed in the routing table when the OSPF route is not present (e.g., due to a failure). The next-hop is R3's IP on the directly connected link.

Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.2 150

Answer

ip route 203.0.113.0 255.255.255.0 10.0.0.6 110

Answer

ip route 0.0.0.0 0.0.0.0 10.0.0.6 150

Question 14

You are connected to R1 via console. R1 has three directly connected subnets: 192.168.1.0/24 (G0/0), 192.168.2.0/24 (G0/1), and 192.168.3.0/24 (G0/2). You need to configure a summary route to be advertised to a neighbor via a static route pointing to Null0 to prevent routing loops. The summary should cover all three subnets.

Accepted Answer

ip route 192.168.0.0 255.255.252.0 Null0. The three subnets 192.168.1.0/24, 192.168.2.0/24, and 192.168.3.0/24 can be summarized as 192.168.0.0/22, which covers 192.168.0.0 to 192.168.3.255. A static route to Null0 ensures that traffic matching the summary but not a more specific route is dropped, preventing routing loops.

Answer

ip route 192.168.1.0 255.255.252.0 Null0

Answer

ip route 192.168.0.0 255.255.255.0 Null0

Answer

ip route 192.168.0.0 255.255.254.0 Null0

Question 15

You are connected to R1 via console. R1 and R2 are connected via two serial links: Serial0/0/0 (10.0.0.1/30) and Serial0/0/1 (10.0.0.5/30). OSPF is configured on both links. However, the OSPF neighbor adjacency is stuck in EXSTART/EXCHANGE state. You suspect a mismatch in OSPF parameters. You need to identify and fix the issue.

Accepted Answer

Check and adjust the MTU on the serial interfaces to match.. The adjacency stuck in EXSTART/EXCHANGE is often due to an MTU mismatch. If one interface has a lower MTU, the DBD packets may be fragmented or rejected, preventing the exchange of LSAs. Setting the same MTU on both sides resolves the issue.

Answer

Check and adjust the OSPF hello and dead timers to match.

Answer

Check and adjust the OSPF network type on the interfaces to match.

Answer

Check and adjust the OSPF area ID on the interfaces to match.

CCNA IP Routing Practice Test 21 — 15 Questions

Exhibit

CCNA IP Routing Practice Test 21 — 15 Questions

Exhibit