300-410 Practice Test 44 — 15 Questions

Question 1

A network engineer runs the following command on Router R1:

R1# show ip route ospf

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

Gateway of last resort is not set

O    10.2.2.0/24 [110/20] via 192.168.12.2, 00:12:34, GigabitEthernet0/0
O IA 10.3.3.0/24 [110/30] via 192.168.13.3, 00:10:21, GigabitEthernet0/1

Based on this output, what can be determined?

Accepted Answer

The route to 10.3.3.0/24 is learned from a different area.. The routing table shows two OSPF routes: one intra-area (O) and one inter-area (O IA). The intra-area route has a cost of 20, and the inter-area route has a cost of 30. Both are reachable via different next hops.

Answer

The route to 10.2.2.0/24 is an external OSPF route.

Answer

Router R1 has a default route configured.

Answer

Both routes have the same administrative distance.

Question 2

A network engineer runs the following command on Router R1:

R1# show ip ospf neighbor 10.1.1.2

Neighbor 10.1.1.2, interface address 192.168.12.2
    In the area 0 via interface GigabitEthernet0/0
    Neighbor priority is 1, State is FULL, 6 state changes
    DR is 10.1.1.2, BDR is 10.1.1.1
    Options is 0x12 (L L S R)
    Dead timer due in 00:00:36
    Neighbor is up for 00:15:42
    Index 1/1/1, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 0, time is 0 msec
    Last retransmission scan time is 0 msec

Based on this output, what is the role of Router R1 on this segment?

Accepted Answer

Router R1 is the Backup Designated Router.. The output shows that the BDR is 10.1.1.1, which is Router R1's router ID. Therefore, R1 is the Backup Designated Router. The DR is 10.1.1.2.

Answer

Router R1 is the Designated Router.

Answer

Router R1 is a DROTHER router.

Answer

Router R1 has no special role on this segment.

Question 3

A network engineer runs the following command on Router R1:

R1# show ip ospf database router 10.1.1.2

OSPF Router with ID (10.1.1.1) (Process ID 1)

Router Link States (Area 0)

LS age: 150
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 10.1.1.2
  Advertising Router: 10.1.1.2
  LS Seq Number: 80000002
  Checksum: 0x1234
  Length: 48
  Number of Links: 2

Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.168.12.2
     (Link Data) Router Interface address: 192.168.12.2
      Number of TOS metrics: 0
       TOS 0 Metrics: 10

Link connected to: a Stub Network
     (Link ID) Network/subnet number: 10.2.2.0
     (Link Data) Network Mask: 255.255.255.0
      Number of TOS metrics: 0
       TOS 0 Metrics: 10

Based on this output, which statement is correct?

Accepted Answer

Router 10.1.1.2 is connected to a transit network and a stub network.. The router LSA from 10.1.1.2 shows two links: one transit network (to the DR address) and one stub network (10.2.2.0/24). The transit link indicates it is connected to a broadcast segment where it is the DR (since it lists its own interface address as DR address).

Answer

Router 10.1.1.2 is the DR on the transit network.

Answer

Router 10.1.1.2 has a cost of 20 to reach the stub network.

Answer

Router 10.1.1.2 is not advertising any external routes.

Question 4

A service provider network uses OSPF with route summarization on Area Border Routers (ABRs). Router R1 (ABR) has the configuration:
router ospf 1
 area 1 range 10.1.0.0 255.255.240.0
 area 1 range 10.1.16.0 255.255.240.0
Router R2 (internal to area 1) shows:
R2# show ip route ospf
     10.1.0.0/20 is subnetted, 1 subnets
O IA 10.1.0.0/20 [110/2] via 10.2.1.1, 00:00:15, Serial0/0/0
     10.1.16.0/20 is subnetted, 1 subnets
O IA 10.1.16.0/20 [110/2] via 10.2.1.1, 00:00:10, Serial0/0/0
     10.1.32.0/20 [110/3] via 10.2.1.2, 00:00:05, Serial0/0/1
R2 is missing a route to 10.1.48.0/20. What is the root cause?

Accepted Answer

The ABR R1 has a missing 'area 1 range 10.1.48.0 255.255.240.0' command.. The ABR R1 configured two summary ranges for area 1, but the missing route 10.1.48.0/20 is not covered by either summary. OSPF summarization on the ABR creates Type 3 LSAs for the configured ranges, but any routes not falling within those ranges are not advertised as summaries and are also not advertised as individual routes (unless the 'no discard-route' option is used). This causes the missing route. The correct fix is to add an additional summary range covering 10.1.48.0/20 or use a broader summary.

Answer

R2 has a routing table limit that prevents installation of the route.

Answer

R1's OSPF process has a distribute-list blocking the route.

Answer

The missing route is a result of OSPF route filtering at the area boundary.

Question 5

A network engineer runs the following command on Router R1:

R1# show ip ospf virtual-links

Virtual Link OSPF_VL0 to router 10.1.1.3 is up
  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 1, via interface GigabitEthernet0/0, Cost of using 10
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:08
  Adjacency State FULL

Based on this output, what can be concluded?

Accepted Answer

The virtual link is functioning correctly and the adjacency is full.. The virtual link to router 10.1.1.3 is up and in FULL state. It is running as a demand circuit, which suppresses hello packets when the link is stable. The transit area is area 1.

Answer

The virtual link is using area 0 as the transit area.

Answer

Router R1 is not receiving hello packets on the virtual link.

Answer

The virtual link has a cost of 1.

Question 6

Two OSPF domains are redistributed into each other on router R1. R1 has:
router ospf 1
 redistribute ospf 2 subnets
router ospf 2
 redistribute ospf 1 subnets
Router R2 (in OSPF 1) shows:
R2# show ip route ospf
O E2 10.1.1.0/24 [110/20] via 10.2.1.1, 00:00:05, Serial0/0/0
O E2 10.2.1.0/24 [110/20] via 10.2.1.1, 00:00:05, Serial0/0/0
R2# traceroute 10.1.1.1 source 10.2.1.2
Type escape sequence to abort.
Tracing the route to 10.1.1.1
  1 10.2.1.1 4 msec 4 msec 4 msec
  2 10.1.1.1 8 msec 8 msec 8 msec
R2# traceroute 10.2.1.1 source 10.1.1.2
Type escape sequence to abort.
Tracing the route to 10.2.1.1
  1 10.1.1.1 4 msec 4 msec 4 msec
  2 10.2.1.1 8 msec 8 msec 8 msec
Traffic between the two domains is taking suboptimal paths. What is the root cause?

Accepted Answer

The redistribution is mutual without any route filtering, causing routing loops.. Mutual redistribution without route filtering creates a routing loop. Routes from OSPF 1 are redistributed into OSPF 2, and then back into OSPF 1, causing suboptimal paths. The traceroute shows traffic going through R1 twice. The fix is to use route tagging and filtering to prevent re-redistribution.

Answer

The 'subnets' keyword is missing from one of the redistribute commands.

Answer

OSPF administrative distance is set incorrectly, preferring external routes.

Answer

R1 has a routing table entry for 10.1.1.0/24 pointing to R2.

Question 7

A network engineer runs the following command on Router R1:

R1# show ip ospf neighbor detail

Neighbor 10.1.1.4, interface address 192.168.14.4
    In the area 0 via interface GigabitEthernet0/2
    Neighbor priority is 1, State is 2WAY, 2 state changes
    DR is 10.1.1.1, BDR is 10.1.1.4
    Options is 0x12 (L L S R)
    Dead timer due in 00:00:38
    Neighbor is up for 00:05:22
    Index 1/1/1, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 0, time is 0 msec
    Last retransmission scan time is 0 msec

Based on this output, what is the problem?

Accepted Answer

The neighbor is in 2WAY state, meaning the adjacency is not fully established.. The neighbor state is 2WAY, not FULL. This indicates that the neighbor relationship has not progressed to full adjacency. On a broadcast network, routers in 2WAY state have exchanged hello packets but have not completed database exchange. This could be due to mismatched MTU, authentication, or other issues, but the key observation is that the state is not FULL.

Answer

Router R1 is the DR and the neighbor is the BDR, so the state is correct.

Answer

The dead timer is about to expire, causing the neighbor to go down.

Answer

The neighbor has a lower priority than R1, so it remains in 2WAY.

Question 8

A network engineer runs the following command on Router R1:

R1# show ipv6 ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
10.1.1.2         1   FULL/BDR        00:00:35    FE80::2          GigabitEthernet0/0
10.1.1.3         1   FULL/DR         00:00:32    FE80::3          GigabitEthernet0/1

Based on this output, which statement is correct regarding OSPFv3?

Accepted Answer

Router R1 has a full adjacency with both neighbors in OSPFv3.. The output shows OSPFv3 neighbors. The neighbor 10.1.1.2 is in state FULL/BDR, meaning it is the Backup Designated Router. The neighbor 10.1.1.3 is in state FULL/DR, meaning it is the Designated Router. The addresses are link-local IPv6 addresses.

Answer

Router R1 is the DR on the segment connected to GigabitEthernet0/0.

Answer

The OSPFv3 process is using IPv4 addresses as router IDs.

Answer

Router R1 is not receiving hello packets from 10.1.1.3.

Question 9

In an iBGP network, router R1 has:
router bgp 65000
 bgp bestpath as-path multipath-relax
 neighbor 10.1.1.2 route-map SET-MED in
route-map SET-MED permit 10
 set metric 50
 neighbor 10.1.1.3 route-map SET-MED2 in
route-map SET-MED2 permit 10
 set metric 100
Router R2 shows:
R2# show ip bgp 192.168.1.0/24
BGP routing table entry for 192.168.1.0/24, version 2
Paths: (2 available, best #2)
  Path #1: via 10.1.1.1, metric 50
  Path #2: via 10.1.1.4, metric 100
R2# show ip route 192.168.1.0
Routing entry for 192.168.1.0/24
  Known via "bgp 65000", distance 200, metric 100
  Last update from 10.1.1.4 00:00:10 Serial0/0/1
R2 is choosing the path with higher metric. What is the root cause?

Accepted Answer

The path with lower MED is from a different AS, so MED is not compared.. BGP best path selection compares MED only if paths come from the same AS. If the paths have different AS_PATH lengths, MED is ignored. The output shows two paths, but the path via 10.1.1.1 might have a different AS_PATH length. The 'bgp bestpath as-path multipath-relax' allows multipath but does not affect MED comparison. The higher metric path is chosen due to a different tie-breaker (e.g., lower neighbor IP).

Answer

The route-map on R1 is misconfigured; it should set metric on the neighbor statement.

Answer

R2 has a higher local preference for the path via 10.1.1.4.

Answer

The 'bgp bestpath as-path multipath-relax' command causes MED to be ignored.

Question 10

Examine the following OSPF configuration on router R1:

router ospf 1
 network 10.0.0.0 0.255.255.255 area 0
 network 192.168.1.0 0.0.0.255 area 1

What is the effect of this configuration?

Accepted Answer

All interfaces with IP addresses in the 10.0.0.0/8 range will be enabled for OSPF in area 0, and interfaces in 192.168.1.0/24 will be in area 1.. The network statements define which interfaces participate in OSPF and assign them to areas. The first statement covers all interfaces with IP addresses starting with 10.x.x.x, and the second covers 192.168.1.x. This is a valid configuration.

Answer

Only the interface with IP 10.0.0.1 will be in area 0; all other 10.x.x.x interfaces are ignored.

Answer

The configuration is invalid because OSPF process 1 cannot have two network statements in different areas.

Answer

The configuration will cause a routing loop between area 0 and area 1.

Question 11

Consider this OSPFv3 configuration on router R2:

ipv6 router ospf 10
 router-id 2.2.2.2
 area 0 authentication ipsec spi 256 md5 1234567890abcdef1234567890abcdef

interface GigabitEthernet0/0
 ipv6 address 2001:db8:1::1/64
 ipv6 ospf 10 area 0

What is the effect of this configuration?

Accepted Answer

OSPFv3 will use IPsec MD5 authentication for all packets in area 0, including on GigabitEthernet0/0.. The area authentication command under OSPFv3 enables IPsec authentication for the entire area. The interface is enabled for OSPFv3 in area 0, so it will use the area authentication. However, OSPFv3 authentication uses IPsec AH or ESP; the configuration shown is valid.

Answer

Authentication is applied only to the GigabitEthernet0/0 interface, not the entire area.

Answer

The configuration is invalid because OSPFv3 does not support IPsec authentication.

Answer

The router-id is missing, so OSPFv3 will not start.

Question 12

Which TWO commands would a network engineer use to verify OSPFv2 neighbor state and adjacency issues on a Cisco IOS router? (Choose TWO.)

Accepted Answer

show ip ospf neighbor. The 'show ip ospf neighbor' command displays the state of all OSPF neighbors, while 'debug ip ospf adj' provides real-time adjacency events. 'show ip route ospf' shows routes, not neighbor states; 'show ip ospf interface' shows per-interface details but not neighbor states directly; 'show ip protocols' displays routing process info, not neighbor states.

Answer

show ip route ospf

Answer

show ip ospf interface

Answer

show ip protocols

Question 13

Two routers R1 and R2 are connected via Ethernet. R1 has:
interface GigabitEthernet0/0
 ip ospf network point-to-point
R2 has default OSPF network type (broadcast). R1 shows:
R1# show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
10.2.2.2          0   FULL/  -        00:00:35    10.1.1.2        GigabitEthernet0/0
R2 shows:
R2# show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
10.1.1.1          1   FULL/DR        00:00:30    10.1.1.1        GigabitEthernet0/0
R1 is not installing OSPF routes from R2. What is the root cause?

Accepted Answer

OSPF network type mismatch prevents proper LSA exchange, causing R1 to ignore routes from R2.. OSPF network type mismatch: R1 is point-to-point, R2 is broadcast. On the point-to-point side, R1 expects no DR/BDR election and uses a different LSA format. The broadcast side sees R1 as DR (because R1's priority is 0? Actually R1 has priority 0? Output shows R1's neighbor has priority 0, but R2 shows R1 as DR. This inconsistency causes adjacency but routes are not exchanged properly due to LSA type mismatch. The fix is to match network types.

Answer

R1 has a higher OSPF priority, causing it to become DR and not accept routes.

Answer

The dead timer mismatch causes adjacency to be unstable.

Answer

R2 is not configured with the same OSPF process ID.

Question 14

Examine this OSPF configuration snippet on router R3:

router ospf 1
 network 10.1.1.0 0.0.0.255 area 0
 default-information originate always

What is the effect of the default-information originate always command?

Accepted Answer

R3 will unconditionally advertise a default route into OSPF as an external LSA type 5.. The command injects a default route (0.0.0.0/0) into the OSPF domain as an external LSA type 5, regardless of whether the router has a default route in its routing table. The 'always' keyword forces advertisement even without a default route.

Answer

R3 will advertise a default route into OSPF only if it has a default route in its routing table.

Answer

R3 will advertise a default route only if it is an ASBR.

Answer

The command is invalid because default-information originate requires a route-map.

Question 15

Consider this OSPF configuration on router R4:

router ospf 1
 network 192.168.1.0 0.0.0.255 area 0
 neighbor 10.0.0.2

What is the effect of the neighbor statement?

Accepted Answer

The neighbor command is ignored because the network type is broadcast by default on Ethernet interfaces.. The neighbor command is used in OSPF for non-broadcast multi-access (NBMA) networks to manually specify neighbors. However, the interface used to reach 10.0.0.2 must be configured with the appropriate network type (e.g., point-to-multipoint or non-broadcast). If the network type is broadcast or point-to-point, the neighbor command is ignored.

Answer

R4 will attempt to form an OSPF adjacency with 10.0.0.2 over any interface that can reach it.

Answer

R4 will send unicast OSPF packets to 10.0.0.2, but only if the interface is in area 0.

Answer

The configuration is invalid because the neighbor command must include a priority.