300-410 Layer 3 Technologies Practice Test 9 — 15 Questions

Question 1

A network engineer is configuring policy-based routing (PBR) on a Cisco IOS XE router. The router has two interfaces: GigabitEthernet0/0 (10.1.1.1/24) and GigabitEthernet0/1 (10.2.2.1/24). The engineer wants to route traffic from subnet 10.1.1.0/24 to a next-hop 10.2.2.2 for HTTP traffic, while all other traffic follows the routing table. The engineer creates a route map named PBR-MAP with a match statement for HTTP and a set statement for the next-hop. Which two additional steps are required to complete the configuration? (Choose two.)

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Apply the route map to the ingress interface using the `ip policy route-map PBR-MAP` command.. PBR requires a route map that matches traffic using an ACL and sets a next-hop. The route map must then be applied to the ingress interface with `ip policy route-map`. The ACL identifies HTTP traffic, and the interface application ensures the policy is evaluated for incoming packets from the specified subnet.

Answer

Enable `ip local policy` globally to apply the route map to all interfaces.

Answer

Configure a match statement for the source subnet 10.1.1.0/24 in the route map.

Answer

Enable `ip routing` globally to allow PBR to function.

Question 2

A network engineer is configuring a Cisco IOS XE router to support IPv6. The router needs to obtain an IPv6 address automatically from the local link and then use that address to communicate with other devices on the same link. Which command should be used on the interface to enable this behavior?

Accepted Answer

ipv6 address autoconfig. The command 'ipv6 address autoconfig' enables SLAAC, which allows the router to automatically configure an IPv6 address based on router advertisements received on the link. This method does not require a DHCPv6 server and is suitable for obtaining an address from the local link. The other options either require manual configuration, a DHCPv6 server, or only provide a link-local address. Therefore, 'ipv6 address autoconfig' is the correct choice for automatic address assignment from the local link.

Answer

ipv6 address dhcp

Answer

ipv6 address eui-64

Answer

ipv6 enable

Question 3

A network administrator is configuring a Cisco IOS XE router to authenticate EIGRP neighbors using SHA-256. The router is running EIGRP AS 100. Which command correctly enables SHA-256 authentication for EIGRP on the interface GigabitEthernet0/0?

Accepted Answer

ip authentication mode eigrp 100 sha-256. EIGRP SHA-256 authentication is enabled per interface with `ip authentication mode eigrp 100 sha-256`. This must be accompanied by a key chain and the `ip authentication key-chain eigrp 100 <name>` command. The other options either enable MD5, specify only the key chain, or use an invalid command.

Answer

ip authentication mode eigrp 100 md5

Answer

eigrp authentication mode sha-256

Answer

ip authentication key-chain eigrp 100 SHA256-KEY

Question 4

A network engineer is troubleshooting an EIGRP network. Router R1 is not forming an adjacency with R2 over a Frame Relay point-to-point subinterface. The engineer verifies that IP connectivity exists and that EIGRP is enabled on the interface with the correct AS number. Which action is most likely to resolve the adjacency issue?

Accepted Answer

Verify that EIGRP hello and hold timers match on both routers.. EIGRP adjacency formation requires matching hello and hold timers, as well as matching authentication and K-values. On a Frame Relay point-to-point subinterface, the most likely cause of an adjacency failure, after verifying IP connectivity and EIGRP AS number, is a timer mismatch. Ensuring that hello and hold timers are identical on both routers will allow the adjacency to form. Other options like changing the subinterface type or disabling split horizon are not relevant to this specific issue.

Answer

Configure the interface as a multipoint subinterface.

Answer

Disable split horizon on the physical interface.

Answer

Configure the 'no ip split-horizon eigrp' command on the subinterface.

Question 5

A network engineer is configuring EIGRP named mode on a Cisco IOS XE router. The engineer wants to enable authentication for EIGRP neighbors using SHA-256. Which two commands are required to complete the authentication configuration? (Choose two.)

Accepted Answer

`authentication mode sha-256` under the address-family ipv4 unicast configuration.. In EIGRP named mode on Cisco IOS XE, authentication is configured under the address-family. To enable SHA-256 authentication, you must first set the authentication mode with `authentication mode sha-256`, then specify the key chain with `key-chain <name>`. These two commands are required under the address-family ipv4 unicast configuration. The key chain itself must be created globally, but that is not the EIGRP-specific configuration.

Answer

`authentication mode md5` under the address-family ipv4 unicast configuration.

Answer

`authentication key-chain <name>` under the interface configuration.

Answer

`key chain <name>` in global configuration mode.

Question 6

A network engineer is configuring a Cisco IOS-XE router to redistribute routes from EIGRP AS 100 into OSPF process 1. The EIGRP routes include several external routes that were learned from another autonomous system. The engineer wants to ensure that only internal EIGRP routes are redistributed into OSPF. Which command should be used?

Accepted Answer

redistribute eigrp 100 route-map INTERNAL-ONLY. To redistribute only internal EIGRP routes into OSPF, a route map must be used with the match route-type internal command. The redistribute command alone does not provide a direct filter for internal routes. The route map is then referenced in the redistribute statement. This ensures external EIGRP routes are not injected into OSPF.

Answer

redistribute eigrp 100 subnets

Answer

redistribute eigrp 100 metric-type 1

Answer

redistribute eigrp 100 match internal

Question 7

A network engineer is deploying a DMVPN Phase 3 hub-and-spoke topology using Cisco IOS XE routers. The hub router is configured with `ip nhrp redirect` and each spoke with `ip nhrp shortcut`. The engineer notices that spoke-to-spoke traffic is still flowing through the hub instead of taking a direct path. Which action should the engineer take to enable direct spoke-to-spoke communication?

Accepted Answer

Ensure that the hub tunnel interface is configured with `ip nhrp redirect` and spokes with `ip nhrp shortcut`.. DMVPN Phase 3 requires the hub to be configured with `ip nhrp redirect` and each spoke with `ip nhrp shortcut`. The redirect mechanism informs the originating spoke of a better path, and the shortcut feature allows the spoke to dynamically build a direct tunnel. Without these, traffic continues via the hub. Ensuring both commands are present is the correct action.

Answer

Configure `ip nhrp network-id` with the same value on all routers.

Answer

Enable `ip nhrp map multicast dynamic` on the hub tunnel interface.

Answer

Configure `ip nhrp nhs` on the hub pointing to each spoke's tunnel IP address.

Question 8

A network engineer is troubleshooting an OSPFv2 adjacency between two Cisco IOS-XE routers on a broadcast segment. The adjacency remains in EXSTART state. The engineer verifies that the interface MTU values match and that both routers are in the same area. Which command should the engineer use to further diagnose the issue?

Accepted Answer

debug ip ospf adj. The EXSTART state indicates that OSPF routers are attempting to exchange database description packets to determine master/slave and initial sequence numbers. Using debug ip ospf adj will display these packets and any errors, such as MTU mismatches or sequence number issues, that prevent progression to EXCHANGE. This is the most direct way to diagnose the problem.

Answer

show ip ospf database

Answer

show ip ospf interface

Answer

show ip ospf neighbor detail

Question 9

A network engineer is configuring a static route on a Cisco IOS XE router to reach the network 10.10.10.0/24 via the next-hop 192.168.1.1. The engineer wants the route to be used only if the next-hop is reachable via a specific interface, GigabitEthernet0/1. Which configuration achieves this requirement?

Accepted Answer

ip route 10.10.10.0 255.255.255.0 192.168.1.1 track 1, with a track object that monitors GigabitEthernet0/1 line protocol.. To condition a static route on the reachability of a next-hop via a specific interface, the engineer must use object tracking. A track object monitors the interface's line protocol, and the static route references it with the track keyword. This ensures the route is only active when the interface is up, preventing blackholing. Simply specifying the interface in the static route does not provide conditional behavior.

Answer

ip route 10.10.10.0 255.255.255.0 192.168.1.1 name VIA_GI0/1

Answer

ip route 10.10.10.0 255.255.255.0 GigabitEthernet0/1 192.168.1.1

Answer

ip route 10.10.10.0 255.255.255.0 192.168.1.1 GigabitEthernet0/1

Question 10

A network engineer is configuring a Cisco IOS XE router for IPv6 OSPFv3. The router is connected to a single broadcast segment and must form an adjacency with a neighbor. The engineer has enabled IPv6 unicast routing and configured an IPv6 address on the interface. Which additional command is required on the interface to enable OSPFv3?

Accepted Answer

ipv6 ospf 1 area 0. OSPFv3 is enabled on a per-interface basis using the `ipv6 ospf process-id area area-id` command. Unlike OSPFv2, there are no network statements in OSPFv3 router configuration. The engineer must enter interface configuration mode and issue `ipv6 ospf 1 area 0` to enable OSPFv3 on that interface. Without this, the interface does not participate in OSPFv3, and no adjacency forms.

Answer

ospfv3 1 ipv6 area 0

Answer

network 2001:db8::/64 area 0

Answer

ipv6 router ospf 1

Question 11

A network engineer is configuring a Cisco IOS-XE router to authenticate OSPFv2 neighbors using MD5. The engineer wants to ensure that only routers with the correct password can form an adjacency. Which command is required on the interface?

Accepted Answer

ip ospf authentication message-digest. To enable OSPF MD5 authentication on an interface, the ip ospf authentication message-digest command is required. It activates MD5 authentication for OSPF packets on that interface. Additionally, the MD5 key must be configured with ip ospf message-digest-key. Both commands are necessary, but the authentication command is the one that enables the authentication type.

Answer

ip ospf message-digest-key 1 md5 <password>

Answer

ip ospf authentication-key <password>

Answer

area 0 authentication message-digest

Question 12

A network engineer is configuring OSPFv3 on a Cisco IOS XE router. The router has two interfaces: GigabitEthernet0/0 and GigabitEthernet0/1. The engineer wants to enable OSPFv3 on both interfaces and ensure that they participate in area 0. Which two commands are required to accomplish this? (Choose two.)

Accepted Answer

ipv6 ospf 1 area 0. To enable OSPFv3, the engineer must create the OSPFv3 routing process with ipv6 router ospf, and then enable OSPFv3 on each interface with ipv6 ospf area. OSPFv3 does not use network commands; interface-level configuration is mandatory. The area ID must match on all interfaces that should form adjacencies. This combination ensures the interfaces participate in area 0.

Answer

router ospf 1

Answer

network 2001:DB8:1::/64 area 0

Answer

ipv6 ospf network point-to-point

Question 13

A network engineer is troubleshooting an OSPFv2 network. Area 0 consists of four routers: R1, R2, R3, and R4. R1 is the designated router (DR) on the broadcast segment connecting all four routers. R2 is the backup designated router (BDR). The engineer notices that R3 and R4 are not forming full adjacencies with R1 and R2. The engineer verifies that the OSPF network type is broadcast, hello and dead timers match, and area IDs are correct. What is the most likely cause of the adjacency issue?

Accepted Answer

The MTU mismatch between the interfaces.. In OSPF, MTU mismatch is a common cause of adjacency failures. During the ExStart/Exchange state, OSPF routers exchange DBD packets that include the MTU. If the MTU values differ, the routers will not proceed to the Loading state and will remain in ExStart/Exchange. Since R1 and R2 are DR and BDR, they have formed an adjacency with each other, but R3 and R4 likely have a different MTU on their interfaces, preventing them from forming full adjacencies with the DR and BDR.

Answer

The OSPF priority is set to 0 on R3 and R4.

Answer

The authentication type mismatch.

Answer

The OSPF router IDs are not unique.

Question 14

A network engineer is configuring OSPFv2 on a Cisco IOS XE router. The router is connected to a broadcast multi-access segment with three other OSPF routers. The engineer wants to ensure that this router becomes the Designated Router (DR) for the segment, and that it does not relinquish the DR role if another router with a higher priority is added later. Which configuration achieves this?

Accepted Answer

Set the OSPF priority to 255 on the interface and configure the router with the highest router ID on the segment.. To become DR and remain DR, the router must win the election and then not be preempted. Setting the highest OSPF priority (255) and the highest router ID on the segment guarantees victory. Because OSPF DR election is non-preemptive, the DR role is not taken away when a new router with higher priority is added; the new router becomes BDR or DROTHER. Thus, the combination of highest priority and highest router ID on the segment achieves the goal.

Answer

Set the OSPF priority to 255 on the interface and configure the router with the highest router ID in the OSPF domain.

Answer

Set the OSPF priority to 0 on all other routers on the segment.

Answer

Set the OSPF priority to 255 on the interface and configure the router with the highest router ID in the area.

Question 15

A network engineer is configuring BGP on a Cisco IOS-XE router. The engineer wants to influence inbound traffic from an ISP by making one path more preferred than another. The engineer plans to use BGP attributes. Which two actions should the engineer take? (Choose two.)

Accepted Answer

Set a lower Multi-Exit Discriminator (MED) value on the more preferred path using the set metric command in a route map.. To influence inbound traffic from an ISP, the engineer can use AS path prepending to make a path less preferred, or set a lower MED on the more preferred path. Both attributes are propagated to the ISP and affect its decision. Local preference and weight are local to the Autonomous System and affect outbound traffic, while origin is a tiebreaker and not typically used for this purpose.

Answer

Configure the set origin command to IGP on the less preferred path to make it less attractive.

Answer

Modify the local preference attribute on the less preferred path to a higher value.

Answer

Use the set weight command on the more preferred path to make it preferred by the ISP.