34 IP Connectivity: Routing & OSPF Practice Questions & Answers

Every IP Connectivity: Routing & OSPF practice question from the Cisco CCNA 200-301 Practice Test, with the correct answer and a short explanation.

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1. On router R1, show ip route lists this entry: "L 192.168.10.1/32 is directly connected, GigabitEthernet0/0". What does this L entry represent?
- A.The whole subnet attached to GigabitEthernet0/0
- B.A static route configured toward a local interface
- C.The router's own interface address as a host route✓ Answer
- D.A subnet learned from a link-state routing protocol
Code L (local) marks a /32 host route for the router's own IPv4 address on that interface. It is created automatically, together with a C (connected) route for the attached subnet, whenever the interface is up/up and has an address, and it lets the router recognize packets addressed to itself. The attached subnet is the separate C entry, static routes use S, and OSPF routes use O.
Ref QB-WFN5C6Source: Cisco CCNA 200-301 Exam Topics — 3.1.a Routing protocol codeReport a problem with this question
2. Router R2 shows this route: "O 172.16.40.0/24 [110/3] via 10.0.12.2, 00:02:10, GigabitEthernet0/1". What do the numbers 110 and 3 in the brackets mean?
- A.110 is the route's age; 3 is the number of paths
- B.110 is the OSPF process ID; 3 is the hop count
- C.110 is the OSPF cost; 3 is the administrative distance
- D.110 is the administrative distance; 3 is the OSPF cost✓ Answer
The bracket in a routing table entry is always [administrative distance/metric]. OSPF's default administrative distance is 110, and its metric is a cumulative cost, here 3. The route's age (00:02:10) and exit interface appear after the next hop, and OSPF does not use hop count as its metric.
Ref QB-FY6N48Source: Cisco CCNA 200-301 Exam Topics — 3.1.e Administrative distance and 3.1.f MetricReport a problem with this question
3. Router R3's routing table begins with "Gateway of last resort is not set" and contains no 0.0.0.0/0 entry. A packet arrives for 198.51.100.25, which matches none of the routes. What does R3 do?
- A.It buffers the packet until a matching route appears
- B.It drops the packet and can return ICMP unreachable✓ Answer
- C.It floods the packet out every interface that is up
- D.It sends the packet out its first connected interface
A router forwards only packets that match an entry in its routing table. With no default route (gateway of last resort not set), a packet that matches nothing is discarded, and the router may send an ICMP destination unreachable message back to the source. Routers do not flood unknown destinations the way switches flood unknown MAC addresses, and they do not hold packets while waiting for routes.
Ref QB-XFZFH7Source: Cisco CCNA 200-301 Exam Topics — 3.1.g Gateway of last resortReport a problem with this question
4. On router R4, show ipv6 route includes: "O 2001:db8:5::/64 [110/2] via FE80::2, GigabitEthernet0/1". Why is the next hop a link-local address instead of a global unicast address?
- A.The destination network is itself a link-local IPv6 prefix
- B.Neighbors send IPv6 routing updates from link-local addresses✓ Answer
- C.A link-local next hop marks the network as directly connected
- D.The route is misconfigured and will not forward any traffic
IPv6 interior routing protocols source their updates from the sending interface's link-local address, so the receiving router records the neighbor's FE80:: address as the next hop. Because the same link-local address can exist on every link, the exit interface is always shown with it. The destination 2001:db8:5::/64 is a global prefix, the route is learned through OSPF (code O) rather than connected, and it forwards normally.
Ref QB-CY4NK4Source: Cisco CCNA 200-301 Exam Topics — 3.1.d Next hopReport a problem with this question
5. An engineer configures 192.168.50.1/24 on GigabitEthernet0/2 of router R5, but the interface is still administratively shut down. What does R5's IPv4 routing table contain for this interface?
- A.Both C and L routes, each flagged as inactive
- B.A local (L) route but no connected (C) route
- C.A connected (C) route but no local (L) route
- D.No connected (C) route and no local (L) route✓ Answer
Connected and local routes are installed only when the interface has an address and is up/up. An administratively down interface contributes neither the C route for 192.168.50.0/24 nor the L host route for 192.168.50.1/32; both appear together once the interface is enabled and comes up. The routing table does not keep inactive placeholders for down interfaces.
Ref QB-UFXFZ3Source: Cisco CCNA 200-301 Exam Topics — 3.1.a Routing protocol codeReport a problem with this question
6. Router R6 shows the entry "S 172.20.0.0/16 [5/0] via 10.0.0.2", while its other static routes show [1/0]. What does the 5 in this entry indicate?
- A.An administrative distance manually set to 5✓ Answer
- B.A metric of 5 assigned to the static route
- C.A destination located five router hops away
- D.The fifth static route entered in the config
The first number in the bracket is the administrative distance. Static routes default to AD 1, so a value of 5 means the engineer configured a different AD for this route. The second number is the metric, which is always 0 for a static route; static routes carry no hop count or ordering value.
Ref QB-DYFYR5Source: Cisco CCNA 200-301 Exam Topics — 3.1.e Administrative distanceReport a problem with this question
7. Router R7 has these routes: S* 0.0.0.0/0 [1/0] via 203.0.113.1 O 172.16.0.0/16 [110/20] via 10.0.0.1 R 172.16.8.0/22 [120/3] via 10.0.0.5 S 172.16.10.64/26 [1/0] via 10.0.0.9 A packet arrives for 172.16.10.130. Which next hop does R7 use?
- A.10.0.0.1, via 172.16.0.0/16
- B.203.0.113.1, via 0.0.0.0/0
- C.10.0.0.5, via 172.16.8.0/22✓ Answer
- D.10.0.0.9, via 172.16.10.64/26
The router picks the longest prefix that actually contains the destination. The /26 starting at 172.16.10.64 covers only .64 through .127, so .130 is outside it. The /22 starting at 172.16.8.0 covers 172.16.8.0 through 172.16.11.255, which includes 172.16.10.130. The /16 and the default also match but are less specific. The RIP route's higher AD of 120 does not matter, because AD only compares routes to the identical prefix.
Ref QB-VFAT65Source: Cisco CCNA 200-301 Exam Topics — 3.2.a Longest prefix matchReport a problem with this question
8. Router R8 learns 10.1.1.0/24 through OSPF from two neighbors: via 192.168.1.2 with a total cost of 30 and via 192.168.2.2 with a total cost of 20. R8 also has a static route for 10.1.0.0/16 via 203.0.113.1. Which next hop does R8 use for a packet to 10.1.1.5?
- A.203.0.113.1, because static AD 1 beats OSPF 110
- B.Both OSPF paths, load-shared in a 2:3 ratio
- C.192.168.1.2, since a higher cost means more bandwidth
- D.192.168.2.2, the OSPF path with the lower cost✓ Answer
The router first applies longest prefix match: the OSPF /24 is more specific than the static /16, so the static route's lower AD never comes into play for 10.1.1.5. Between the two OSPF paths to the same /24, the same protocol and AD apply, so the lower metric wins and only the cost-20 path via 192.168.2.2 is installed. OSPF load-shares only across paths with equal cost, and a lower OSPF cost, not a higher one, indicates the faster path.
Ref QB-AYDY82Source: Cisco CCNA 200-301 Exam Topics — 3.2.c Routing protocol metricReport a problem with this question
9. Router R9 learns 192.168.70.0/24 from three sources at once: OSPF with cost 2, EIGRP with metric 3072, and RIP with 1 hop. All administrative distances are at their defaults. Which route does R9 install in its routing table?
- A.EIGRP, because AD 90 beats 110 and 120✓ Answer
- B.All three, as equal-cost load-sharing paths
- C.RIP, because a 1-hop metric is the smallest
- D.OSPF, because cost 2 beats the EIGRP metric
When different sources offer the same prefix and prefix length, the route with the lowest administrative distance is installed. Default ADs are EIGRP 90, OSPF 110 and RIP 120, so EIGRP wins. Metrics are calculated differently by each protocol and cannot be compared across protocols, so the smaller-looking OSPF cost or RIP hop count is irrelevant here.
Ref QB-W87FPUSource: Cisco CCNA 200-301 Exam Topics — 3.2.b Administrative distanceReport a problem with this question
10. Router R10 runs OSPF and learns 10.30.0.0/24 from two neighbors, 10.0.1.2 and 10.0.2.2. Both paths have a total OSPF cost of 20, and default settings are in use. What does R10 do with these two paths?
- A.Keeps only the path from the higher router ID
- B.Installs only the path with the lower next hop
- C.Installs both and shares traffic across them✓ Answer
- D.Uses only the path that was learned first
Within a single routing protocol, the path with the lowest metric is installed. When two or more paths to the same prefix tie on metric, the router installs them all as equal-cost multipath routes, shown as multiple 'via' lines, and shares traffic across them. OSPF does not break metric ties by router ID, arrival order or next-hop address.
Ref QB-VAC42ZSource: Cisco CCNA 200-301 Exam Topics — 3.2.c Routing protocol metricReport a problem with this question
11. Router R11 has a static route for 10.40.0.0/16 with default settings. It also runs OSPF, which advertises both 10.40.0.0/16 and 10.40.8.0/24 to it. Which routes forward packets to 10.40.8.9 and to 10.40.20.1?
- A.Static /16 for both, because AD 1 beats AD 110
- B.OSPF /24 for 10.40.8.9 and static /16 for 10.40.20.1✓ Answer
- C.OSPF for both, because OSPF has a lower metric
- D.OSPF /24 for 10.40.8.9 and OSPF /16 for 10.40.20.1
For the identical prefix 10.40.0.0/16, the static route (AD 1) beats OSPF (AD 110), so only the static /16 is installed. The OSPF 10.40.8.0/24 has no competitor and is installed. 10.40.8.9 matches both the /24 and the /16, and the longer /24 wins. 10.40.20.1 is outside 10.40.8.0/24, so only the static /16 matches.
Ref QB-DTH9MZSource: Cisco CCNA 200-301 Exam Topics — 3.2 Router forwarding decision (longest prefix match, then administrative distance)Report a problem with this question
12. Router R12 has these routes and no default route: O 192.168.5.0/24 [110/2] via 10.1.1.1 O 192.168.5.128/25 [110/3] via 10.1.1.2 S 192.168.5.200/32 [1/0] via 10.1.1.3 Which next hop is used for a packet to 192.168.5.201?
- A.10.1.1.1, via the /24 route
- B.10.1.1.2, via the /25 route✓ Answer
- C.No match, so it is dropped
- D.10.1.1.3, via the /32 route
A /32 host route matches only that single address, 192.168.5.200, so it does not match .201 despite its AD of 1. The /25 starting at 192.168.5.128 covers .128 through .255 and contains .201; the /24 also matches but is shorter. The longest matching prefix is the /25, so the packet goes to 10.1.1.2.
Ref QB-WAQE72Source: Cisco CCNA 200-301 Exam Topics — 3.2.a Longest prefix matchReport a problem with this question
13. Branch router R13 reaches the internet through an OSPF-learned default route. The engineer adds a static default route through a backup ISP link and wants it used only if the OSPF default disappears. Which administrative distance should the static route have?
- A.An AD of 130✓ Answer
- B.An AD of 100
- C.An AD of 255
- D.An AD of 1
A floating static route must have a higher administrative distance than the route it backs up, so it stays out of the routing table while that route exists. OSPF's AD is 110, so 130 works. An AD of 1 or 100 is lower than 110 and would replace the OSPF default immediately. An AD of 255 means the route is considered unusable and is never installed, so it would provide no backup.
Ref QB-ETVKS2Source: Cisco CCNA 200-301 Exam Topics — 3.3.d Floating staticReport a problem with this question
14. Router R14 uses an EIGRP-learned route to 10.60.0.0/16. A floating static route to the same prefix with an administrative distance of 200 is also configured. While the EIGRP route is healthy, where does the static route appear?
- A.In the routing table, sharing load with the EIGRP route
- B.Only in the running configuration, not the routing table✓ Answer
- C.In the routing table, marked as a backup with AD 200
- D.Nowhere, because the router discards it as a duplicate
Only the lowest-AD source for a prefix is installed, so the EIGRP route (AD 90) is in the routing table and the static route (AD 200) is held back. The static route remains in the running configuration and is installed automatically if the EIGRP route is withdrawn. Routes from different sources never load-share, and the routing table does not list inactive backups.
Ref QB-TANEPWSource: Cisco CCNA 200-301 Exam Topics — 3.3.d Floating staticReport a problem with this question
15. On router R15, an engineer adds an IPv6 static route to 2001:db8:20::/64 that lists only fe80::2 as the next hop, with no interface. The route does not work. What is the problem?
- A.The prefix length must be given as a dotted-decimal mask
- B.A link-local next hop must be paired with an exit interface✓ Answer
- C.fe80::2 must be written in full before it is accepted
- D.IPv6 static routes can never use a link-local next hop
Link-local addresses are unique only on a single link, so fe80::2 could exist behind every interface and the router cannot tell which one to use. A static route with a link-local next hop must therefore also name the exit interface. A global unicast next hop can be used alone because it is resolved recursively. IPv6 uses /length notation, not dotted masks, and abbreviated addresses are valid.
Ref QB-BTTK9XSource: Cisco CCNA 200-301 Exam Topics — 3.3 Configure and verify IPv4 and IPv6 static routingReport a problem with this question
16. Router R16 has IPv6 addresses on its LAN and WAN interfaces plus an IPv6 static default route (::/0), and it can ping IPv6 neighbors on both links. However, LAN hosts receive no router advertisements and cannot reach any remote IPv6 network through R16. What is the most likely cause?
- A.The default route must use a /128 prefix length
- B.The LAN interface has no link-local IPv6 address
- C.The hosts still need an IPv4 default gateway set
- D.IPv6 unicast routing has not been enabled on R16✓ Answer
Until IPv6 unicast routing is enabled globally, the router behaves like an IPv6 host: it can use its own addresses and ping neighbors, but it does not forward IPv6 packets between interfaces or send router advertisements. The IPv6 default route is ::/0 (a /128 is a single-host route), IPv4 settings do not affect IPv6 forwarding, and a link-local address is created automatically on any IPv6-enabled interface.
Ref QB-UAZRUXSource: Cisco CCNA 200-301 Exam Topics — 3.3 Configure and verify IPv4 and IPv6 static routingReport a problem with this question
17. Router R17 is configured with a static host route to 192.168.30.10/32 using next hop 10.0.0.2. The only path toward 10.0.0.2 was the connected subnet 10.0.0.0/30 on Serial0/0/0, and that interface is now down/down. The host route is missing from the routing table. Why?
- A.A /32 host route can only point out an exit interface
- B.Static routes appear only after the router is reloaded
- C.The host route needs a default route to be installed too
- D.Its next hop 10.0.0.2 is no longer reachable by any route✓ Answer
A static route that names a next hop is installed only while the router can resolve that next hop through another route, found by a recursive lookup. When Serial0/0/0 went down, the connected route to 10.0.0.0/30 disappeared, so 10.0.0.2 became unreachable and the static host route was withdrawn. It returns automatically when the interface comes back up. Host routes can use a next hop, and no reload or default route is needed.
Ref QB-CT6XEYSource: Cisco CCNA 200-301 Exam Topics — 3.3.c Host routeReport a problem with this question
18. Router R1 connects to a shared Ethernet segment. Its OSPF neighbor list shows neighbor 10.255.0.2 in state FULL/DR and neighbor 10.255.0.3 in state FULL/BDR. What role does R1 hold on that segment?
- A.The BDR on the segment
- B.Still in the Init state
- C.The DR on the segment
- D.A DROTHER on the segment✓ Answer
The role after the slash in the neighbor State column describes the neighbor, not the local router. Since other routers already hold the DR and BDR roles and R1 is FULL with both, R1 must be a DROTHER. It cannot be in Init, because the adjacencies are already FULL.
Ref QB-ZASEQ5Source: Cisco CCNA 200-301 Exam Topics — 3.4.c OSPF broadcast networks (DR/BDR selection)Report a problem with this question
19. On a broadcast segment, R1 (interface priority 50) is the OSPF DR and R2 (priority 10) is the BDR. A new router, R3, is connected to the segment with interface priority 200 and OSPF is enabled. No processes are cleared and no router reloads. What is the result?
- A.R3 becomes a DROTHER and R1 remains DR✓ Answer
- B.R3 immediately replaces R2 as the BDR
- C.R3 forces a new DR and BDR election
- D.R3 immediately takes over as the DR
OSPF DR/BDR election is non-preemptive: once a DR and BDR exist, a newly arriving router with a higher priority does not displace either one. R3 becomes a DROTHER and would only win a role after the DR or BDR fails or the OSPF process is restarted.
Ref QB-HTXKA6Source: Cisco CCNA 200-301 Exam Topics — 3.4.c OSPF broadcast networks (DR/BDR selection); IETF RFC 2328Report a problem with this question
20. An engineer must guarantee that branch router BR3 never becomes the DR or BDR on its LAN segment, while BR3 still forms OSPF adjacencies with whichever routers are elected. Which setting on BR3's LAN interface achieves this?
- A.Interface OSPF priority set to 0✓ Answer
- B.Interface OSPF priority set to 1
- C.Interface set as OSPF passive
- D.Interface OSPF priority set to 255
An OSPF interface priority of 0 makes the router ineligible for DR or BDR, yet it still exchanges hellos and goes FULL with the DR and BDR. Priority 1 is the default and keeps it eligible, 255 makes it the most preferred candidate, and a passive interface stops hellos so no adjacency forms at all.
Ref QB-8K3YKRSource: Cisco CCNA 200-301 Exam Topics — 3.4.c OSPF broadcast networks (DR/BDR selection)Report a problem with this question
21. Router R5 has no router-id command configured. When OSPF starts, these interfaces are up/up: GigabitEthernet0/0 192.168.50.1, GigabitEthernet0/1 172.16.200.1, Loopback0 10.0.0.1 and Loopback1 10.0.0.9. Which OSPF router ID does R5 choose?
- A.172.16.200.1
- B.10.0.0.1
- C.10.0.0.9✓ Answer
- D.192.168.50.1
Without a manually configured router ID, OSPF uses the highest IPv4 address on an up/up loopback interface before considering any physical interface. The highest loopback address is 10.0.0.9, so it wins even though 192.168.50.1 is the highest address overall.
Ref QB-Q3WSZQSource: Cisco CCNA 200-301 Exam Topics — 3.4.d OSPF router IDReport a problem with this question
22. R2's OSPF process has been running with router ID 192.168.1.1, taken from a physical interface. An administrator adds Loopback0 with address 10.99.99.99, but R2 still reports router ID 192.168.1.1. What explains this?
- A.The RID is chosen only when the OSPF process starts✓ Answer
- B.Loopbacks are used only if no physical interface is up
- C.The RID always uses the highest address on the router
- D.A loopback must be advertised into OSPF before use
OSPF selects its router ID once, when the process starts, and keeps it until the process is restarted (for example with clear ip ospf process) or the router reloads. After a restart the loopback would win, because a loopback is preferred over physical interfaces and the RID does not need to be advertised.
Ref QB-9KEASSSource: Cisco CCNA 200-301 Exam Topics — 3.4.d OSPF router IDReport a problem with this question
23. R1 and R2 share an Ethernet link in the same area and subnet with matching hello and dead timers. Each router repeatedly lists the other in the EXSTART or EXCHANGE state, and the adjacency never reaches FULL. What is the most likely cause?
- A.The hello and dead timers differ
- B.The OSPF process IDs differ
- C.The area IDs on the link differ
- D.The interface MTU values differ✓ Answer
Database Description packets carry the interface MTU, and a router rejects DBDs from a neighbor with a larger MTU, so a mismatch stalls the routers in ExStart/Exchange. Timer or area mismatches stop hellos from being accepted, so the routers would never get that far, and process IDs are only locally significant.
Ref QB-R3957SSource: Cisco CCNA 200-301 Exam Topics — 3.4.a OSPF neighbor adjacencies; IETF RFC 2328Report a problem with this question
24. Engineers are bringing up OSPF between two routers that share one Ethernet subnet. Which value can differ between the two routers without preventing a FULL adjacency?
- A.The OSPF area ID of the link
- B.The OSPF process ID number✓ Answer
- C.The interface subnet mask
- D.The OSPF dead interval timer
The OSPF process ID is locally significant and is never carried in hello packets, so it may differ. The area ID, hello/dead timers and subnet/mask are checked in every hello, and a mismatch in any of them prevents the neighbor relationship.
Ref QB-6KCA9PSource: Cisco CCNA 200-301 Exam Topics — 3.4.a OSPF neighbor adjacenciesReport a problem with this question
25. R1's interface toward R2 uses OSPF hello 10 s and dead 40 s. To speed up convergence, a colleague changes only R2's facing interface to hello 5 s and dead 20 s. Both interfaces are in the same area and subnet. What happens?
- A.They never become OSPF neighbors✓ Answer
- B.They stall in the ExStart state
- C.They reach FULL using R1's timers
- D.They reach FULL using R2's timers
OSPF does not negotiate timers: each router discards hellos whose hello or dead interval differs from its own, so the routers never even reach Init/2-Way. A stall in ExStart is the symptom of an MTU mismatch, which happens only after hellos have been accepted.
Ref QB-N375PNSource: Cisco CCNA 200-301 Exam Topics — 3.4.a OSPF neighbor adjacenciesReport a problem with this question
26. Two routers are joined by a direct Ethernet link, and both interfaces are set to the OSPF point-to-point network type. Each router lists the other with the state FULL/-. What does the dash indicate?
- A.No DR or BDR is elected on this link✓ Answer
- B.The adjacency is still being negotiated
- C.The neighbor is a DROTHER on the link
- D.The neighbor's priority is set to 0
On a point-to-point network type there can only be one neighbor, so OSPF skips the DR/BDR election entirely and the role field shows a dash. FULL means the databases are fully synchronized; a priority-0 neighbor on a broadcast segment would appear as DROTHER instead.
Ref QB-7KQMEQSource: Cisco CCNA 200-301 Exam Topics — 3.4.b OSPF point-to-pointReport a problem with this question
27. Five OSPF routers share one Ethernet LAN. Router R4 lists R1 as FULL/DR, R2 as FULL/BDR, and R3 and R5 as 2WAY/DROTHER. A technician worries that something is broken. Which assessment is correct?
- A.Hello timers differ on R3 and R5
- B.An MTU mismatch exists with R3 and R5
- C.Nothing, because DROTHERs go FULL only with the DR and BDR✓ Answer
- D.R3 and R5 have duplicate router IDs
On a broadcast segment, DROTHERs form full adjacencies only with the DR and BDR and deliberately stop at 2-Way with each other, which keeps the number of adjacencies small. A timer mismatch would prevent any neighbor entry, and an MTU mismatch would show ExStart/Exchange rather than a stable 2WAY.
Ref QB-P3JFUPSource: Cisco CCNA 200-301 Exam Topics — 3.4.c OSPF broadcast networks (DR/BDR selection)Report a problem with this question
28. R1 can reach network 10.40.0.0/24 over two paths that are identical except for R1's outgoing link: one path leaves on a FastEthernet (100 Mbps) interface and the other on a GigabitEthernet (1 Gbps) interface. OSPF uses the default reference bandwidth, and R1 installs both paths as equal-cost routes. Why?
- A.OSPF shares unequal-cost paths by default
- B.Both interfaces compute to a cost of 10
- C.OSPF metric counts hops, not bandwidth
- D.Both interfaces compute to a cost of 1✓ Answer
OSPF cost is the reference bandwidth divided by the interface bandwidth, and with the default 100 Mbps reference any interface of 100 Mbps or faster gets the minimum cost of 1. Raising the reference bandwidth consistently on all routers (auto-cost reference-bandwidth) makes the faster link cheaper; OSPF does not use hop count or balance across unequal costs.
Ref QB-4KNMWKSource: Cisco CCNA 200-301 Exam Topics — 3.4 Single-area OSPFv2 (interface cost)Report a problem with this question
29. On an Ethernet segment with an elected DR and BDR, a DROTHER router detects a link change and must send a link-state update. To which destination IP address does it send that update?
- A.224.0.0.5
- B.224.0.0.6✓ Answer
- C.224.0.0.2
- D.224.0.0.10
DROTHERs send updates to 224.0.0.6, the AllDRouters group that only the DR and BDR listen to; the DR then refloods the change to every OSPF router at 224.0.0.5. The address 224.0.0.2 is all routers on the subnet (used by HSRPv1), and 224.0.0.10 is used by EIGRP.
Ref QB-K3GFBKSource: Cisco CCNA 200-301 Exam Topics — 3.4.c OSPF broadcast networks; IETF RFC 2328Report a problem with this question
30. R1's GigabitEthernet0/2 connects to user LAN 10.30.0.0/24, where no other routers exist. The interface is already included in OSPF, and an administrator now makes it a passive interface. What is the effect?
- A.No hellos sent; 10.30.0.0/24 is still advertised✓ Answer
- B.Hellos still sent; 10.30.0.0/24 is withdrawn
- C.Hellos only received; 10.30.0.0/24 still advertised
- D.No hellos sent; 10.30.0.0/24 is withdrawn
A passive OSPF interface stops sending and processing hellos, so no adjacency can form on it, but its connected subnet is still included in the router's LSA and advertised to the rest of the area. This is the standard way to advertise user LANs without exposing OSPF to hosts.
Ref QB-5H3T3NSource: Cisco CCNA 200-301 Exam Topics — 3.4.a OSPF neighbor adjacencies (passive interface)Report a problem with this question
31. Hosts in VLAN 30 use a statically configured default gateway of 10.30.0.1. The company adds a second router to the VLAN for redundancy. Which approach keeps the hosts reaching other networks if either router fails, with no change to host settings?
- A.Assign both routers the same interface IP
- B.Run OSPF on the hosts toward both routers
- C.Use an FHRP with a shared virtual IP and MAC✓ Answer
- D.List both router IPs as gateways on each host
A first hop redundancy protocol lets the routers share a virtual IP (set as the hosts' gateway) and a virtual MAC; if the active router fails, another router takes over that same IP and MAC, so hosts need no change. Editing every host or running a routing protocol on hosts defeats the goal, and identical real interface IPs cause an address conflict.
Ref QB-NZ8YNNSource: Cisco CCNA 200-301 Exam Topics — 3.5 First hop redundancy protocolsReport a problem with this question
32. A network mixes routers from two different vendors, and the pair serving a user VLAN must share one redundant default gateway. Which first hop redundancy protocol is an open IETF standard rather than a Cisco-proprietary protocol?
- A.HSRPv2
- B.GLBP
- C.VRRP✓ Answer
- D.HSRP
VRRP is defined by the IETF (RFC 5798) and is supported by many vendors, using Master and Backup roles. HSRP in either version and GLBP are Cisco-proprietary, so they are not suitable when a non-Cisco router must participate.
Ref QB-4HQFWKSource: IETF RFC 5798 (VRRP); Cisco CCNA 200-301 Exam Topics — 3.5 First hop redundancy protocolsReport a problem with this question
33. An engineer wants both gateway routers on one VLAN to forward host traffic at the same time, using a single redundancy group and a single virtual IP configured on every host. Which first hop redundancy protocol does this natively, and how?
- A.HSRP, by sending gratuitous ARP from both routers
- B.GLBP, by replying to ARP with different virtual MACs✓ Answer
- C.VRRP, by having the backup forward half the traffic
- D.HSRP, by electing two active routers in one group
In GLBP the active virtual gateway answers host ARP requests for the one virtual IP with the virtual MACs of different active virtual forwarders, spreading hosts across up to four routers in a single group. HSRP and VRRP have only one active/master forwarder per group; they share load only by configuring multiple groups.
Ref QB-MZVMGMSource: Cisco CCNA 200-301 Exam Topics — 3.5 First hop redundancy protocolsReport a problem with this question
34. Routers DS1 (HSRP priority 110) and DS2 (HSRP priority 100) share a virtual gateway, with all other HSRP settings left at their defaults. DS1 was active, then rebooted, and DS2 took over. DS1 is now back online and healthy. What happens?
- A.Both routers share the active role
- B.DS1 waits 10 seconds, then becomes active
- C.DS2 stays active and DS1 becomes standby✓ Answer
- D.DS1 resumes the active role at once
HSRP preemption is disabled by default, so a returning router with higher priority does not take back the active role; DS2 remains active until it fails or preemption is enabled on DS1. VRRP differs here because its preemption is enabled by default, and HSRP never has two active routers in one group.
Ref QB-7HSFEQSource: Cisco CCNA 200-301 Exam Topics — 3.5 First hop redundancy protocols (HSRP defaults)Report a problem with this question

1. On router R1, show ip route lists this entry: "L 192.168.10.1/32 is directly connected, GigabitEthernet0/0". What does this L entry represent?

2. Router R2 shows this route: "O 172.16.40.0/24 [110/3] via 10.0.12.2, 00:02:10, GigabitEthernet0/1". What do the numbers 110 and 3 in the brackets mean?

3. Router R3's routing table begins with "Gateway of last resort is not set" and contains no 0.0.0.0/0 entry. A packet arrives for 198.51.100.25, which matches none of the routes. What does R3 do?

4. On router R4, show ipv6 route includes: "O 2001:db8:5::/64 [110/2] via FE80::2, GigabitEthernet0/1". Why is the next hop a link-local address instead of a global unicast address?

5. An engineer configures 192.168.50.1/24 on GigabitEthernet0/2 of router R5, but the interface is still administratively shut down. What does R5's IPv4 routing table contain for this interface?

6. Router R6 shows the entry "S 172.20.0.0/16 [5/0] via 10.0.0.2", while its other static routes show [1/0]. What does the 5 in this entry indicate?

7. Router R7 has these routes: S* 0.0.0.0/0 [1/0] via 203.0.113.1 O 172.16.0.0/16 [110/20] via 10.0.0.1 R 172.16.8.0/22 [120/3] via 10.0.0.5 S 172.16.10.64/26 [1/0] via 10.0.0.9 A packet arrives for 172.16.10.130. Which next hop does R7 use?

8. Router R8 learns 10.1.1.0/24 through OSPF from two neighbors: via 192.168.1.2 with a total cost of 30 and via 192.168.2.2 with a total cost of 20. R8 also has a static route for 10.1.0.0/16 via 203.0.113.1. Which next hop does R8 use for a packet to 10.1.1.5?

9. Router R9 learns 192.168.70.0/24 from three sources at once: OSPF with cost 2, EIGRP with metric 3072, and RIP with 1 hop. All administrative distances are at their defaults. Which route does R9 install in its routing table?

10. Router R10 runs OSPF and learns 10.30.0.0/24 from two neighbors, 10.0.1.2 and 10.0.2.2. Both paths have a total OSPF cost of 20, and default settings are in use. What does R10 do with these two paths?

11. Router R11 has a static route for 10.40.0.0/16 with default settings. It also runs OSPF, which advertises both 10.40.0.0/16 and 10.40.8.0/24 to it. Which routes forward packets to 10.40.8.9 and to 10.40.20.1?

12. Router R12 has these routes and no default route: O 192.168.5.0/24 [110/2] via 10.1.1.1 O 192.168.5.128/25 [110/3] via 10.1.1.2 S 192.168.5.200/32 [1/0] via 10.1.1.3 Which next hop is used for a packet to 192.168.5.201?

13. Branch router R13 reaches the internet through an OSPF-learned default route. The engineer adds a static default route through a backup ISP link and wants it used only if the OSPF default disappears. Which administrative distance should the static route have?

14. Router R14 uses an EIGRP-learned route to 10.60.0.0/16. A floating static route to the same prefix with an administrative distance of 200 is also configured. While the EIGRP route is healthy, where does the static route appear?

15. On router R15, an engineer adds an IPv6 static route to 2001:db8:20::/64 that lists only fe80::2 as the next hop, with no interface. The route does not work. What is the problem?

16. Router R16 has IPv6 addresses on its LAN and WAN interfaces plus an IPv6 static default route (::/0), and it can ping IPv6 neighbors on both links. However, LAN hosts receive no router advertisements and cannot reach any remote IPv6 network through R16. What is the most likely cause?

17. Router R17 is configured with a static host route to 192.168.30.10/32 using next hop 10.0.0.2. The only path toward 10.0.0.2 was the connected subnet 10.0.0.0/30 on Serial0/0/0, and that interface is now down/down. The host route is missing from the routing table. Why?

18. Router R1 connects to a shared Ethernet segment. Its OSPF neighbor list shows neighbor 10.255.0.2 in state FULL/DR and neighbor 10.255.0.3 in state FULL/BDR. What role does R1 hold on that segment?

19. On a broadcast segment, R1 (interface priority 50) is the OSPF DR and R2 (priority 10) is the BDR. A new router, R3, is connected to the segment with interface priority 200 and OSPF is enabled. No processes are cleared and no router reloads. What is the result?

20. An engineer must guarantee that branch router BR3 never becomes the DR or BDR on its LAN segment, while BR3 still forms OSPF adjacencies with whichever routers are elected. Which setting on BR3's LAN interface achieves this?

21. Router R5 has no router-id command configured. When OSPF starts, these interfaces are up/up: GigabitEthernet0/0 192.168.50.1, GigabitEthernet0/1 172.16.200.1, Loopback0 10.0.0.1 and Loopback1 10.0.0.9. Which OSPF router ID does R5 choose?

22. R2's OSPF process has been running with router ID 192.168.1.1, taken from a physical interface. An administrator adds Loopback0 with address 10.99.99.99, but R2 still reports router ID 192.168.1.1. What explains this?

23. R1 and R2 share an Ethernet link in the same area and subnet with matching hello and dead timers. Each router repeatedly lists the other in the EXSTART or EXCHANGE state, and the adjacency never reaches FULL. What is the most likely cause?

24. Engineers are bringing up OSPF between two routers that share one Ethernet subnet. Which value can differ between the two routers without preventing a FULL adjacency?

25. R1's interface toward R2 uses OSPF hello 10 s and dead 40 s. To speed up convergence, a colleague changes only R2's facing interface to hello 5 s and dead 20 s. Both interfaces are in the same area and subnet. What happens?

26. Two routers are joined by a direct Ethernet link, and both interfaces are set to the OSPF point-to-point network type. Each router lists the other with the state FULL/-. What does the dash indicate?

27. Five OSPF routers share one Ethernet LAN. Router R4 lists R1 as FULL/DR, R2 as FULL/BDR, and R3 and R5 as 2WAY/DROTHER. A technician worries that something is broken. Which assessment is correct?

29. On an Ethernet segment with an elected DR and BDR, a DROTHER router detects a link change and must send a link-state update. To which destination IP address does it send that update?

30. R1's GigabitEthernet0/2 connects to user LAN 10.30.0.0/24, where no other routers exist. The interface is already included in OSPF, and an administrator now makes it a passive interface. What is the effect?

31. Hosts in VLAN 30 use a statically configured default gateway of 10.30.0.1. The company adds a second router to the VLAN for redundancy. Which approach keeps the hosts reaching other networks if either router fails, with no change to host settings?

32. A network mixes routers from two different vendors, and the pair serving a user VLAN must share one redundant default gateway. Which first hop redundancy protocol is an open IETF standard rather than a Cisco-proprietary protocol?

33. An engineer wants both gateway routers on one VLAN to forward host traffic at the same time, using a single redundancy group and a single virtual IP configured on every host. Which first hop redundancy protocol does this natively, and how?

34. Routers DS1 (HSRP priority 110) and DS2 (HSRP priority 100) share a virtual gateway, with all other HSRP settings left at their defaults. DS1 was active, then rebooted, and DS2 took over. DS1 is now back online and healthy. What happens?

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