300-410 Infrastructure Services Practice Test 2 — 15 Questions

Question 1

A network engineer is deploying DMVPN Phase 2 with OSPF as the routing protocol. The hub router is configured as a broadcast network, and spokes are configured as non-broadcast. OSPF adjacencies are not forming between spokes and the hub. Which configuration change is required on the spoke routers to allow OSPF neighbor formation?

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

Accepted Answer

Add neighbor statements on the spokes pointing to the hub's tunnel IP address.. In a DMVPN Phase 2 network with OSPF, if the hub is configured as a broadcast network and spokes as non-broadcast, the spokes will not send or listen for multicast OSPF hellos. To form adjacencies, each spoke must be configured with a neighbor statement pointing to the hub's tunnel IP address. This forces the spoke to send unicast hellos to the hub, which the hub can respond to, enabling OSPF neighbor formation.

Answer

Configure the spokes as point-to-multipoint network.

Answer

Configure the hub as a point-to-multipoint network.

Answer

Configure the hub with a neighbor statement for each spoke.

Question 2

A network engineer is configuring a Cisco IOS router to use TACACS+ for authorization of EXEC commands. The engineer wants to ensure that if the TACACS+ server is unavailable, the router will allow users to execute EXEC commands with privilege level 1. Which two commands are required to achieve this? (Choose two.)

Accepted Answer

username admin privilege 1 secret cisco. To allow EXEC commands with privilege level 1 when the TACACS+ server is unavailable, configure EXEC authorization to fall back to local using 'aaa authorization exec default group tacacs+ local'. Additionally, define a local user with privilege level 1 using 'username admin privilege 1 secret cisco'. This ensures that the fallback local authorization grants the intended privilege level.

Answer

aaa authorization exec default group tacacs+ if-authenticated

Answer

aaa authorization commands 1 default group tacacs+ local

Answer

aaa authorization exec default group tacacs+ none

Question 3

A network administrator is configuring DMVPN Phase 3 with IKEv2 on a hub router. The spoke routers must be able to dynamically establish direct spoke-to-spoke tunnels when needed. Which configuration on the hub is required to support this behavior?

Accepted Answer

Enable NHRP redirect and configure NHRP shortcut on the spokes.. DMVPN Phase 3 introduces NHRP redirect on the hub and NHRP shortcut on the spokes. When the hub receives a packet from one spoke destined to another spoke's network, it sends an NHRP redirect message to the source spoke. The source spoke then initiates an NHRP resolution for the destination spoke's NBMA address and installs a shortcut route, allowing direct tunnel establishment. Both commands are essential.

Answer

Configure the hub with a unique NHRP network ID and enable NHRP authentication.

Answer

Enable IPsec tunnel protection on the hub and configure IKEv2 with multiple proposals.

Answer

Configure the hub as a route reflector and enable BGP next-hop-self on all spokes.

Question 4

A company deploys MPLS Layer 3 VPNs with OSPF as the PE-CE routing protocol. The customer requires that routes learned from one site be redistributed into BGP with specific community attributes for traffic engineering. Which configuration step is necessary on the PE router to ensure that OSPF routes are redistributed with the correct BGP extended community for VPNv4?

Accepted Answer

Configure route-target export under the VRF address family.. The route-target export extended community is essential for MPLS L3VPN route distribution. It is configured under the VRF address family and is automatically attached to routes redistributed from OSPF into BGP. This allows remote PEs to import the routes into the correct VRF. The other options either do not achieve the goal or are not the standard configuration step.

Answer

Set the OSPF domain ID to match the BGP autonomous system number.

Answer

Enable OSPF as a BGP network statement under the global BGP configuration.

Answer

Configure a route-map to set the BGP extended community attribute to the route-target value.

Question 5

A network administrator is configuring a Cisco IOS router for MPLS L3VPN. The router is a PE device with a VRF named CUSTOMER. The administrator wants to ensure that routes from the CUSTOMER VRF are exported with the correct route target and that routes from other VRFs are not imported into CUSTOMER. Which configuration is required to accomplish this?

Accepted Answer

Under the VRF definition, configure 'route-target export 65000:100' and 'route-target import 65000:100'.. Route targets are essential for controlling import and export of routes between VRFs. The export route target is attached to routes when advertised, and the import route target determines which routes are accepted into the VRF. Configuring both export and import with the same value ensures proper route propagation and isolation. The other options either do not control route targets or use incorrect syntax.

Answer

Under the VRF definition, configure 'route-target both 65000:100'.

Answer

Under the BGP configuration, configure 'address-family ipv4 vrf CUSTOMER' and then 'redistribute connected'.

Answer

Under the VRF definition, configure 'rd 65000:100'.

Question 6

A network administrator is deploying MPLS Layer 3 VPNs across a service provider core. The core consists of P and PE routers running OSPF as the IGP. The administrator wants to ensure that customer routes are not leaked into the global routing table and that VPNv4 prefixes are exchanged correctly. Which BGP address family must be activated on the PE routers to carry customer VPN routes?

Accepted Answer

address-family ipv4 vrf . To carry customer VPN routes on a PE router, the correct BGP address family is address-family ipv4 vrf . This enables the PE to exchange IPv4 routes with the CE within the VRF, which are then redistributed into MP-BGP VPNv4 for transport across the MPLS core. The vpnv4 unicast address family is used between PEs, not with CEs.

Answer

address-family vpnv4 unicast

Answer

address-family ipv6 unicast

Answer

address-family ipv4 unicast

Question 7

A network administrator is configuring a Cisco IOS router to act as a DHCP server for a remote subnet. The router is not directly connected to that subnet. Which command is necessary to configure the router to assign IP addresses from a pool to clients on that remote subnet?

Accepted Answer

ip dhcp pool. To configure a Cisco IOS router as a DHCP server for a remote subnet, the administrator must create a DHCP pool using the ip dhcp pool command. Within the pool, the network command specifies the subnet, and other parameters like default router and DNS server are defined. The router will then assign addresses from that pool to clients on that subnet, even if they are not directly connected, as long as DHCP requests reach the router via a relay agent.

Answer

ip dhcp excluded-address

Answer

ip helper-address

Answer

ip dhcp relay

Question 8

A network engineer is troubleshooting an MPLS L3VPN setup where customer routes are not being advertised from one PE router to another. The engineer suspects an issue with the BGP configuration on the PE routers. Which two BGP configuration elements are required on the PE routers to exchange VPNv4 routes? (Choose two.)

Accepted Answer

Configure BGP neighbor statements for the remote PE routers.. To exchange VPNv4 routes, PE routers must have BGP neighbor statements configured to establish sessions, and they must activate the VPNv4 address family under BGP. Without these two elements, BGP will not carry VPNv4 prefixes. The other options, while necessary for MPLS L3VPN operation, are not BGP configuration elements; they are configured under VRF or interface configurations.

Answer

Configure route targets under the VRF definition.

Answer

Enable MPLS LDP on all interfaces.

Answer

Configure a route distinguisher (RD) for each VRF.

Question 9

A network administrator is troubleshooting a DMVPN Phase 3 configuration on a Cisco IOS router. The hub router is configured with 'ip nhrp redirect' and the spoke with 'ip nhrp shortcut'. The administrator notices that spoke-to-spoke traffic is still flowing through the hub instead of directly between spokes. Which action should be taken to allow direct spoke-to-spoke communication?

Accepted Answer

Verify that the hub router has 'ip nhrp redirect' enabled and that the spokes have 'ip nhrp shortcut' enabled on the tunnel interface.. DMVPN Phase 3 requires the hub to be configured with 'ip nhrp redirect' and the spokes with 'ip nhrp shortcut' on their tunnel interfaces. These commands allow the hub to inform the source spoke of a better path, and the spoke to dynamically create a direct tunnel to the destination spoke. Without both, traffic continues through the hub.

Answer

Configure 'ip nhrp map multicast dynamic' on the hub.

Answer

Ensure that the spoke routers have a route to the destination spoke's tunnel IP address via the hub.

Answer

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

Question 10

A service provider is deploying MPLS Traffic Engineering (TE) with RSVP-TE to ensure bandwidth guarantees for critical traffic. The network uses OSPF as the IGP. An engineer notices that TE tunnels are not being established even though the IGP has full reachability. Which configuration is required to enable MPLS TE on the interfaces and allow RSVP to signal the tunnels?

Accepted Answer

Enable MPLS TE and RSVP on all interfaces along the path, and configure OSPF with the mpls-te area option.. To enable MPLS TE, you must enable MPLS TE and RSVP on all interfaces that will participate in TE tunnels. Also, the IGP (OSPF) must be configured to advertise TE link information via the 'mpls-te area' command. This populates the TE database, allowing the headend to compute paths and signal tunnels using RSVP. The other options do not provide the necessary TE signaling or topology information.

Answer

Enable MPLS LDP on all interfaces and configure OSPF with the mpls ldp autoconfig command.

Answer

Configure RSVP authentication and enable MPLS TE on the headend router only.

Answer

Configure BGP with the MPLS TE extended community on all routers.

Question 11

A network engineer is troubleshooting a DMVPN Phase 2 network where spoke-to-spoke tunnels are not forming. The engineer verifies that NHRP registrations are successful and that the hub has routes to all spokes. Which command on the spoke routers is most likely missing to enable direct spoke-to-spoke communication?

Accepted Answer

ip nhrp shortcut. In DMVPN Phase 2, spoke-to-spoke tunnels are established dynamically when a spoke receives a route from another spoke with the next-hop being that spoke's tunnel IP. The spoke must have ip nhrp shortcut configured on its tunnel interface to resolve the destination NBMA address and create a direct tunnel. Without it, the spoke will not build the shortcut route and will continue to forward traffic through the hub.

Answer

ip nhrp map multicast dynamic

Answer

ip next-hop-self

Answer

ip nhrp redirect

Question 12

A network engineer is configuring a Cisco IOS router to act as a DHCP relay agent. The DHCP server is located on a different subnet, and the router's interface facing the clients is configured with the ip helper-address 10.1.1.100 command. Clients report that they are not receiving IP addresses. The engineer verifies that the DHCP server is operational and has a valid scope for the client subnet. Which action should be taken to resolve the issue?

Accepted Answer

Configure the ip forward-protocol udp 67 command on the router.. The ip helper-address command relays UDP broadcasts, including DHCP, by default. However, if the ip forward-protocol udp command has been used to specify a different set of ports, it can disable the default forwarding of DHCP. Re-enabling UDP port 67 restores DHCP relay functionality. This is a subtle but critical configuration detail for DHCP relay operations.

Answer

Configure the DHCP server with the default-router command pointing to the router's interface.

Answer

Add the ip helper-address command on the interface facing the DHCP server.

Answer

Enable the ip dhcp relay information option command on the router.

Question 13

A network administrator is troubleshooting a DMVPN Phase 3 configuration using OSPF as the routing protocol. Spoke routers are not forming OSPF adjacencies with the hub, although IPsec tunnels are up. The hub is configured with 'ip nhrp map multicast dynamic' and 'ip nhrp network-id 100'. Spoke routers have 'ip nhrp map multicast ' and 'ip nhrp nhs '. Which additional configuration is required on the spoke routers to enable OSPF neighbor formation over the DMVPN?

Accepted Answer

Configure 'ip nhrp shortcut' on the spoke routers.. In DMVPN Phase 3, spoke routers require 'ip nhrp shortcut' to enable direct spoke-to-spoke tunnel establishment and to properly integrate NHRP with the routing protocol. Without this, OSPF adjacencies may fail because the spokes do not have the necessary NHRP support for shortcut paths. The hub uses 'ip nhrp redirect' to facilitate this process.

Answer

Configure 'ip ospf network broadcast' on the tunnel interfaces.

Answer

Configure 'ip nhrp redirect' on the spoke routers.

Answer

Configure 'ip nhrp registration no-unique' on the spoke routers.

Question 14

A network administrator is configuring a Cisco IOS router to use PBR to route traffic from the 10.10.10.0/24 subnet to a next-hop of 192.168.1.2. The configuration includes a route-map named PBR-MAP with a match statement for the source subnet and a set ip next-hop 192.168.1.2 statement. After applying the route-map to the interface with ip policy route-map PBR-MAP, the administrator notices that traffic from 10.10.10.0/24 is still following the default routing table. What is the most likely cause?

Accepted Answer

The ip policy route-map command is applied in the wrong direction on the interface.. The ip policy route-map command must be applied in the inbound direction on the interface where traffic enters the router. If applied outbound, the router will not evaluate the policy for incoming packets, and they will be forwarded based on the routing table. Therefore, the most likely cause is that the command was applied in the wrong direction.

Answer

The next-hop IP address 192.168.1.2 is not reachable via the routing table.

Answer

The route-map is missing a set ip next-hop verify-availability command.

Answer

The route-map requires a permit statement with no match clause to allow other traffic.

Question 15

A network administrator is configuring a Cisco IOS XE router as a DHCPv6 server for a dual-stack network. The router must provide IPv6 addresses and DNS server information to clients. The administrator has configured the DHCPv6 pool with the 'address prefix' and 'dns-server' commands. However, clients are not receiving the DNS server information. Which action should be taken to resolve this issue?

Accepted Answer

Ensure that the DHCPv6 pool is configured with the 'dns-server' command and that the clients are requesting the DNS option via the 'option request' in their solicit messages.. In DHCPv6, clients must request specific options, such as DNS servers, by including them in the Option Request Option (ORO) in their Solicit messages. If the client does not request the DNS option, the server will not supply it, even if configured. The administrator should check the client configuration to ensure it requests the DNS server option. The server-side configuration appears correct, so the issue is likely on the client side.

Answer

Configure the 'dns-server' command with the correct IPv6 address of the DNS server.

Answer

Enable the 'ipv6 dhcp server' command on the client-facing interface.

Answer

Configure the 'ipv6 nd ra dns server' command on the interface to provide DNS information via Router Advertisement.