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300-410 · domain

Infrastructure Services

Infrastructure Services covers Cisco IOS/IOS-XE features that provide secure connectivity and network services: DMVPN Phase 3, IPv6 First Hop Security, and AAA with TACACS+. Questions present a configuration goal or symptom and ask for the exact command, feature behavior, or verification output needed to meet it.

106 questions26 easy47 medium33 hard

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What this domain covers

What to know about Infrastructure Services

Be able to select and apply the exact IOS commands that enable DMVPN Phase 3 spoke-to-spoke forwarding, IPv6 First Hop Security filtering, and TACACS+ AAA with fallback. The single most important thing is knowing which command goes on the hub versus the spoke.

DMVPN Phase 3 hub commands: ip nhrp redirect and ip nhrp shortcut for spoke-to-spoke tunnels

IPv6 First Hop Security features including DHCPv6 Guard, RA Guard, and IPv6 snooping

TACACS+ authentication, authorization, and accounting configuration with fallback behavior

Verification and troubleshooting of NHRP mappings, DHCPv6 Guard policy, and AAA server reachability

Watch out for

Common Infrastructure Services exam traps

  • ▸Assuming ip nhrp redirect alone enables spoke-to-spoke tunnels; the spoke also needs ip nhrp shortcut and a route to the destination spoke.
  • ▸Confusing DHCPv6 Guard with RA Guard; DHCPv6 Guard filters DHCPv6 server and client messages, not router advertisements.
  • ▸Forgetting that TACACS+ fallback requires configuring the aaa authentication command with a local or none fallback method after the server group.

Question index

All Infrastructure Services questions (106)

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1

A network engineer is configuring a Cisco IOS XE router to act as a DHCPv6 relay agent. The router is connected to a LAN segment with DHCPv6 clients and must forward DHCPv6 messages to a DHCPv6 server at 2001:DB8::100. The engineer has configured the interface with ipv6 address 2001:DB8:1::1/64 and ipv6 enable. Which command is required to enable DHCPv6 relay on the interface?

Hard
2

A network engineer is configuring a Cisco IOS router to authenticate a branch office VPN client with a digital certificate. The certificate is issued by an external CA, and the engineer must ensure that the router can validate the certificate chain. Which command is required to install the CA certificate?

Medium
3

A network engineer is configuring an MPLS L3VPN on a Cisco IOS XE PE router. The customer edge (CE) router uses eBGP to peer with the PE router. The engineer wants to ensure that the CE can advertise its routes to the PE and that the PE can propagate them to other PE routers via MP-BGP. The engineer has configured the VRF, the PE-CE eBGP session, and MP-BGP on the PE. However, the routes from the CE are not appearing in the MP-BGP table. Which configuration step is most likely missing on the PE router?

Hard
4

A network engineer is configuring a Cisco IOS XE router to support First Hop Redundancy Protocol (FHRP) for a group of hosts on VLAN 10. The design requires that the virtual IP address and virtual MAC address remain the same even if the active router changes. The engineer decides to use Virtual Router Redundancy Protocol (VRRP) version 2. Which statement about VRRPv2 is true?

Medium
5

A network engineer is configuring a Cisco IOS XE router as a Dynamic Multipoint VPN (DMVPN) Phase 3 hub. The hub must support spoke-to-spoke direct tunnels while allowing the hub to remain in the data path for initial spoke-to-spoke communication. The engineer has configured the tunnel interface with 'ip nhrp redirect' on the hub. Which additional command must be configured on the spoke routers to enable them to dynamically create direct tunnels to other spokes?

Medium
6

A company has a Cisco IOS XE router configured with IP SLA and Object Tracking to monitor the reachability of a primary ISP. The router should fail over to a backup ISP when the primary path becomes unreachable. The engineer wants to ensure that the failover occurs quickly and that the primary path is restored when it becomes available again. Which configuration element is required to achieve this behavior?

Medium
7

A company is deploying IPv6 and wants to use stateful DHCPv6 to assign addresses to clients. The network administrator configures the router with the 'ipv6 dhcp pool' command and sets the 'address prefix' and 'dns-server' options. However, clients are not receiving IPv6 addresses. Which additional configuration is required on the client-facing interface to enable stateful DHCPv6?

Hard
8

A network engineer is configuring a Cisco IOS router to support IPv6 OSPFv3. The engineer wants to enable OSPFv3 on an interface and ensure that it forms adjacencies with neighbors. Which command must be used to enable OSPFv3 on an interface?

Easy
9

A network administrator is implementing policy-based routing (PBR) on a Cisco IOS router. The goal is to route traffic from a specific subnet (192.168.1.0/24) through a next-hop of 10.1.1.2 instead of the default route. The administrator has created a route map named PBR-MAP and configured a match statement for the subnet. Which action must be configured in the route map to set the next-hop?

Easy
10

A network engineer is configuring a Cisco IOS XE router to support MPLS Layer 3 VPNs. The engineer has enabled MPLS IP on the core interfaces and configured OSPF as the IGP. Which additional configuration is required on the PE routers to exchange VPNv4 routes with other PE routers?

Easy
11

A network engineer is configuring a Cisco IOS router to act as a Dynamic Host Configuration Protocol (DHCP) relay agent. The router receives DHCP broadcast requests on interface GigabitEthernet0/1 and must forward them to a DHCP server at 10.1.1.100. Which command is required to enable this functionality?

Medium
12

A network engineer is configuring SNMPv3 on a Cisco IOS router. The requirement is to authenticate and encrypt SNMP messages using the user 'admin' with SHA authentication and AES encryption. Which command correctly configures the SNMPv3 user?

Medium
13

A network engineer is configuring a Cisco router as a Dynamic Host Configuration Protocol (DHCP) server for a remote subnet. The router's interface that connects to the remote subnet is GigabitEthernet0/1 with IP address 10.10.10.1/24. The engineer wants the router to assign addresses from the 10.10.10.0/24 pool to clients on that subnet. Which command must be issued in DHCP pool configuration mode to specify the default gateway that clients will receive?

Medium
14

A network engineer is configuring a Cisco IOS router to support MPLS L3VPN. The router will act as a PE router and needs to assign a unique identifier to each customer VRF to allow overlapping address spaces. Which MPLS L3VPN component provides this function?

Easy
15

A network engineer is configuring a Cisco IOS XE router to support a DMVPN Phase 3 hub-and-spoke topology. The hub router must be able to redirect spoke-to-spoke traffic without requiring the spokes to have a direct route to each other. Which technology should be implemented on the hub to enable the hub to inform the originating spoke of the optimal spoke-to-spoke path?

Medium
16

A network administrator is configuring a Cisco IOS router to use NAT overload (PAT) for a small office. The inside network is 192.168.1.0/24, and the router's outside interface is GigabitEthernet0/0 with IP address 203.0.113.5. The administrator enters the following commands: access-list 1 permit 192.168.1.0 0.0.0.255 ip nat inside source list 1 interface GigabitEthernet0/0 overload interface GigabitEthernet0/1 ip address 192.168.1.1 255.255.255.0 ip nat inside interface GigabitEthernet0/0 ip address 203.0.113.5 255.255.255.0 ip nat outside However, hosts on the inside network cannot access the Internet. Which command is missing?

Easy
17

A network engineer is troubleshooting a DHCP relay configuration on a Cisco IOS router. The router is configured with the ip helper-address 10.1.1.1 command on interface GigabitEthernet0/0, but clients on the 192.168.1.0/24 subnet are not receiving IP addresses from the DHCP server at 10.1.1.1. The engineer verifies that the DHCP server is operational and has a pool for 192.168.1.0/24. What is the most likely cause?

Hard
18

A network technician is configuring a Cisco router to act as a DHCP relay agent. The router's interface Gi0/0 is connected to the DHCP clients, and the DHCP server is reachable via interface Gi0/1. Which command must be configured on interface Gi0/0 to forward DHCP requests to the server at 192.168.1.10?

Easy
19

A network engineer is configuring a Cisco IOS router to authenticate OSPFv2 neighbors using MD5. The engineer wants to ensure that the authentication key is not sent in clear text and that the key can be changed without disrupting the adjacency. Which command should be used to configure the key on the interface?

Medium
20

A network engineer configures a Cisco IOS router as a DHCP relay agent. The router interface connected to the DHCP clients is configured with 'ip helper-address 192.168.1.10'. Which type of traffic will be forwarded to the DHCP server at 192.168.1.10 by default?

Easy
21

A network administrator is configuring a Cisco IOS XE router to support IPv6. The administrator wants to enable IPv6 routing and assign an IPv6 address to an interface. Which command must be configured globally to enable IPv6 routing?

Easy
22

A network engineer is implementing MPLS Traffic Engineering (TE) with RSVP-TE. The engineer must ensure that the TE tunnel can be established and that the headend router can signal the path. Which two statements about RSVP-TE operation are true? (Choose two.)

Hard
23

A network engineer is deploying an MPLS L3VPN using BGP as the PE-CE routing protocol. The customer requires that the PE router accept only routes with a specific BGP community and set a local preference of 200 for those routes. Which configuration on the PE router accomplishes this requirement?

Medium
24

A network engineer is configuring a Cisco IOS XE router to support MPLS Traffic Engineering (TE) with RSVP-TE. The engineer has enabled MPLS TE globally and on the interfaces. The engineer wants to ensure that the router can signal an LSP with a specific bandwidth requirement of 100 Mbps. Which command is required to enable RSVP-TE signaling on the interface?

Medium
25

A network engineer is deploying MPLS Layer 3 VPNs on a Cisco IOS XE PE router. The customer VRF CUST_A uses OSPF as the PE-CE routing protocol. The engineer must ensure that OSPF routes from the customer are redistributed into MP-BGP and that the OSPF domain ID is preserved across the MPLS backbone. Which configuration step is required on the PE router?

Hard
26

A service provider is deploying MPLS Traffic Engineering (TE) with RSVP-TE to guarantee bandwidth for critical traffic. The network uses OSPF as the IGP with TE extensions enabled. An engineer notices that a TE tunnel fails to establish because the path computation cannot find a path with sufficient bandwidth, even though the physical links have enough capacity. Which action should the engineer take to ensure that RSVP-TE can reserve bandwidth on the links?

Hard
27

A network engineer is configuring MPLS Traffic Engineering (TE) with RSVP-TE on a Cisco IOS XE router to provide bandwidth guarantees for delay-sensitive traffic. The engineer must ensure that the TE tunnel can signal the required bandwidth and that the path is computed based on available resources. Which two statements about the configuration are true? (Choose two.)

Hard
28

A network administrator is deploying DMVPN Phase 3 with IKEv2. The hub router is configured with a dynamic multipoint VPN tunnel and is using NHRP. Spoke routers are configured to register with the hub. After configuration, the administrator notices that spoke-to-spoke traffic is still going through the hub instead of directly between spokes. Which configuration change is most likely to resolve this issue?

Medium
29

A network engineer is deploying an MPLS Layer 3 VPN for a customer. The customer requires that the provider edge (PE) routers support a unique route distinguisher (RD) per VRF and that the same customer routes be imported into multiple VRFs. Which configuration on the PE router accomplishes this requirement?

Medium
30

A network administrator is configuring a Cisco IOS XE router to act as a DHCP relay agent. The router is connected to a client subnet on GigabitEthernet0/0 and to a DHCP server at 192.168.1.100 on GigabitEthernet0/1. The administrator enters the command 'ip helper-address 192.168.1.100' on GigabitEthernet0/0. Which statement is true about the behavior of this configuration?

Easy
31

A network administrator is deploying a DMVPN Phase 3 hub-and-spoke topology. Spokes must be able to communicate directly with each other without traffic traversing the hub. The administrator has configured NHRP and IPsec on all routers. Which additional configuration is required on the hub to enable direct spoke-to-spoke communication?

Medium
32

A network engineer is configuring a Cisco IOS router to act as a DHCP relay agent. The router receives DHCP discover messages on interface GigabitEthernet0/1 and must forward them to a DHCP server at 10.1.1.100. Which command is required on the router?

Easy
33

A network engineer is deploying MPLS Layer 3 VPNs on Cisco IOS routers. The engineer must ensure that customer routes are properly propagated across the MPLS core and that labels are correctly assigned. Which two protocols are used within the MPLS core to distribute labels and VPNv4 routes? (Choose two.)

Hard
34

A network engineer is configuring a branch router to obtain its WAN interface IPv4 address from an ISP using DHCP. The provider requires the router to send a specific client identifier. Which command must be applied under the interface configuration to meet this requirement?

Medium
35

A network administrator is configuring a GRE tunnel between two Cisco IOS routers. The tunnel must support multicast traffic and be protected by IPsec. Which two statements about the configuration are true? (Choose two.)

Medium
36

A network engineer is configuring a Cisco IOS router as a DHCP server for a subnet. The router must exclude the address 10.10.10.1 from being assigned to clients. Which command correctly accomplishes this?

Easy
37

A network engineer is configuring DMVPN Phase 3 on a hub router. The hub must forward traffic directly between spokes without traversing the hub. Which command is required on the hub to enable this behavior?

Medium
38

A network administrator is configuring a Cisco IOS router to act as a DHCP server for a LAN segment. The administrator wants to exclude a range of IP addresses from being assigned to clients because those addresses are statically assigned to servers and printers. Which command should be used to accomplish this?

Easy
39

A network engineer is configuring a Cisco router to support MPLS Layer 3 VPNs. The engineer needs to enable the router to exchange VPNv4 routes with a provider edge (PE) router. Which address family must be configured under the BGP routing process to support this?

Medium
40

A network engineer is configuring a DMVPN Phase 3 hub-and-spoke topology. Spokes are behind NAT devices and have dynamically assigned public IP addresses. The engineer wants to ensure that spoke-to-spoke traffic can be established directly without traversing the hub. Which technology should be implemented on the hub to achieve this?

Medium
41

A network administrator is deploying MPLS Layer 3 VPNs across a service provider backbone. The provider uses OSPF as the IGP and MP-BGP for VPNv4 route distribution. The administrator notices that VPNv4 routes are not being advertised between PE routers. Which configuration step is most likely missing on the PE routers?

Hard
42

A network technician is configuring a Cisco router to act as a DHCP relay agent. The router's interface GigabitEthernet0/0 is connected to a subnet where clients need to obtain IP addresses from a DHCP server located on a different subnet. Which command is required on the router to enable DHCP relay?

Easy
43

A network technician is configuring a GRE tunnel between two routers. The tunnel source is a physical interface, and the tunnel destination is a loopback interface on the remote router. The technician notices that the tunnel interface is up, but line protocol is down. What is the most likely cause?

Easy
44

A network engineer is configuring a Cisco router to support Network Address Translation (NAT) for a small office. The engineer wants to translate internal private addresses to a single public address using Port Address Translation (PAT). Which command enables PAT by allowing the router to use the interface's IP address for translation?

Medium
45

A network engineer is troubleshooting an MPLS L3VPN where customer routes are not being advertised from one PE to another. The engineer verifies that the VRFs are configured correctly, the IGP is converged, and the PE routers have established an MP-BGP session. Which command should the engineer use to verify that the VPNv4 prefixes are being exchanged correctly?

Medium
46

A network engineer is configuring an MPLS L3VPN. The PE router is running OSPF with the CE router in VRF CUSTOMER. The engineer notices that routes from the customer are being redistributed into the provider's global OSPF process, causing instability. Which configuration change on the PE router will prevent this redistribution while still allowing customer routes to be advertised across the MPLS core?

Medium
47

A network engineer is deploying DMVPN Phase 3 with IPsec protection. The hub router is configured with a multipoint GRE tunnel interface and NHRP. Which two statements are true regarding the configuration that must be applied to the spoke routers to enable direct spoke-to-spoke communication? (Choose two.)

Medium
48

A network engineer is configuring a Cisco IOS XE router to authenticate VPN users against a Microsoft Active Directory server. The router must use RADIUS and send the user's original username without modification. Which command set correctly configures the router to use the AD server at 10.1.1.50 with the shared secret 'Cisco123'?

Medium
49

A network engineer is configuring a Cisco IOS XE router for MPLS L3VPN. The router is a PE device with a VRF named CUSTOMER. The engineer wants to redistribute routes from the VRF into MP-BGP so they can be advertised to a remote PE. The engineer has configured the VRF and assigned interfaces. Which command sequence correctly redistributes the connected routes from the VRF into BGP?

Medium
50

A network administrator is deploying a DMVPN Phase 2 network with EIGRP as the routing protocol. The hub router is configured with a multipoint GRE interface and NHRP. Spokes are configured with tunnel interfaces and are registering with the hub. However, the administrator notices that spoke routers are not forming EIGRP neighbor adjacencies with the hub. Which command is most likely missing on the hub's mGRE interface?

Easy
51

A network administrator needs to configure a Cisco IOS router to send SNMP traps to a management server at 192.168.1.200 using SNMPv2c with the community string 'public'. Which command is required?

Easy
52

A network engineer is implementing CoPP (Control Plane Policing) on a Cisco IOS router to protect the route processor from excessive traffic. The engineer wants to limit ICMP echo requests destined to the router itself to 100 kbps. Which action must be taken to ensure that CoPP applies only to traffic destined to the control plane?

Medium
53

A network administrator is deploying MPLS Layer 3 VPNs on Cisco IOS routers. The administrator must ensure that customer routes are exchanged between PE routers without requiring customer involvement. Which two protocols or features are required to accomplish this? (Choose two.)

Hard
54

A network technician is configuring a Cisco IOS router to act as a DHCP server for a subnet. The technician wants the router to exclude a range of addresses from being assigned to clients. Which command should be used to exclude the addresses?

Easy
55

A network engineer is configuring a Cisco router to act as a DHCP server for a remote subnet. The router's interface connected to the remote subnet is configured with the `ip helper-address` command pointing to the DHCP server. However, clients on the remote subnet are not receiving IP addresses. The engineer verifies that the DHCP server is operational and has a valid pool for the remote subnet. What is the most likely cause of the problem?

Easy
56

A network engineer is configuring a Cisco IOS XE router to act as an IPv6 DHCP server for a LAN segment. The router must provide IPv6 addresses and other configuration parameters to hosts. Which two tasks must the engineer perform to enable stateful DHCPv6 operation on the router? (Choose two.)

Medium
57

A network administrator is configuring a Cisco IOS router as a DHCP server. The router has two interfaces: GigabitEthernet0/0 with IP 192.168.1.1/24 and GigabitEthernet0/1 with IP 10.0.0.1/24. The administrator wants the router to assign addresses from the 192.168.1.0/24 subnet to clients on GigabitEthernet0/0. Which command must be configured in the DHCP pool to ensure that the router only assigns addresses from the correct subnet?

Hard
58

A network administrator is configuring a Cisco IOS XE router to support MPLS L3VPN. The administrator needs to enable MPLS forwarding on an interface that connects to the service provider core. Which command should be applied to the interface?

Easy
59

A network engineer is configuring a Cisco IOS router to act as a DHCP relay agent. The router interface GigabitEthernet0/0 is connected to a subnet with DHCP clients, and the DHCP server is located at 192.168.100.10. Which command must be applied to the interface to forward DHCP requests to the server?

Medium
60

A network engineer is troubleshooting an MPLS L3 VPN where OSPF is used as the PE-CE routing protocol. The customer reports that routes from one site are not being learned at another site. The engineer checks the PE routers and finds that the OSPF routes are present in the VRF routing table but not in the MP-BGP table. What is the most likely cause?

Hard
61

A network engineer is configuring a DMVPN Phase 3 spoke router. The spoke must establish a direct tunnel to another spoke when traffic requires it. The hub is already configured with 'ip nhrp redirect'. Which additional command must be configured on the spoke to enable it to request and receive shortcut replies from the hub?

Medium
62

A network administrator is configuring a Cisco IOS router to support MPLS Layer 3 VPN. The administrator needs to enable the provider edge (PE) router to exchange VPNv4 routes with other PE routers. Which two configurations are required on the PE router to enable MP-BGP for VPNv4? (Choose two.)

Medium
63

A network engineer configures a Cisco IOS router with the command 'ip dhcp excluded-address 10.10.10.1 10.10.10.20'. The DHCP pool is defined as 'ip dhcp pool LAN' with network 10.10.10.0 /24. Which statement accurately describes the effect of the excluded-address command?

Medium
64

A network engineer is troubleshooting an MPLS L3VPN where customer routes are not being propagated between PE routers. The engineer verifies that the MP-BGP session between the PEs is established and that VRFs are configured correctly. Which of the following is the most likely cause for the missing routes?

Hard
65

A network administrator is deploying IPv6 First Hop Security features on a Cisco Catalyst switch. The goal is to prevent rogue DHCPv6 servers from assigning addresses to clients. The administrator configures DHCPv6 Guard on the switch. Which additional configuration is necessary to ensure that DHCPv6 Guard operates correctly?

Hard
66

A network engineer is configuring a Cisco IOS router to act as a DHCP server for a subnet 10.10.10.0/24. The engineer wants to ensure that the router provides the default gateway, DNS server, and domain name to DHCP clients. Which three commands must be configured in the DHCP pool? (Choose three.)

Medium
67

A network engineer is troubleshooting a DMVPN Phase 3 network where spoke-to-spoke communication is not working. The hub is configured with ip nhrp redirect, and spokes are configured with ip nhrp shortcut. The routing protocol is OSPF, and the hub is configured with ip nhrp map multicast dynamic. The engineer notices that when a spoke pings another spoke's LAN IP, the first few pings fail, but subsequent pings succeed. However, the engineer wants to eliminate the initial packet loss. Which of the following is the most likely cause of the initial packet loss?

Hard
68

A network engineer is configuring a Cisco router to act as a DHCPv6 server for a dual-stack network. The engineer wants to provide IPv6 addresses to clients and also supply them with DNS server addresses. Which DHCPv6 message type should the server use to send the DNS server information to the clients?

Easy
69

A network engineer is configuring IPsec VPN on a Cisco IOS router. The engineer wants to ensure that only traffic from the 192.168.1.0/24 subnet to the 10.0.0.0/24 subnet is encrypted, while all other traffic is sent unencrypted. Which configuration element is used to define this traffic?

Hard
70

A service provider is deploying MPLS Traffic Engineering (TE) with RSVP-TE to ensure bandwidth guarantees for critical traffic. The network engineer has configured an MPLS TE tunnel on a Cisco IOS XE router. The tunnel must be able to signal an explicit path that includes a specific link with a reserved bandwidth of 50 Mbps. Which RSVP-TE object is used to carry the explicit route information in the Path message?

Hard
71

A network engineer is configuring a Cisco IOS router to send syslog messages to a remote syslog server at 10.1.1.100. The router's loopback0 interface is 192.168.1.1. The engineer wants syslog messages to be sourced from the loopback0 interface. Which command must be configured?

Medium
72

A network engineer is configuring a Cisco IOS XE router as a DHCPv6 server for a dual-stack network. The router must provide IPv6 addresses and other configuration parameters to clients on VLAN 20. The engineer has configured a DHCPv6 pool named POOL1 with the address prefix 2001:DB8:20::/64 and the DNS server 2001:DB8::53. The clients are not receiving IPv6 addresses. Which additional configuration is required on the router's VLAN 20 interface to ensure DHCPv6 clients can obtain addresses?

Medium
73

A network engineer is troubleshooting an IPv4 Network Address Translation (NAT) configuration on a Cisco IOS router. The router is configured with NAT overload (PAT) using the command ip nat inside source list 1 interface GigabitEthernet0/0 overload. Inside hosts cannot reach the Internet. The engineer verifies that interface GigabitEthernet0/0 is up and has an IP address, and that access list 1 permits the inside subnet. Which additional configuration is most likely missing?

Medium
74

A network engineer is configuring a Cisco IOS router to support a new branch office that requires dynamic IPv4 addressing for clients. The router is already configured with a DHCP pool named BRANCH_POOL. The engineer notices that clients are not receiving IP addresses. Which command, when applied globally, is required to enable the DHCP service on the router?

Medium
75

A network administrator is deploying MPLS Layer 3 VPNs with Cisco IOS XE routers. The administrator wants to ensure that customer routes are not leaked into the global routing table and that each VPN instance maintains separate routing and forwarding tables. Which of the following must be configured on the PE routers to achieve this isolation?

Hard
76

A network engineer is configuring a DMVPN Phase 3 hub router. Spoke routers are behind dynamic NAT and cannot receive inbound connections. The engineer needs to ensure that spoke-to-spoke traffic flows directly without traversing the hub. Which technology must be enabled on the hub to achieve this?

Medium
77

A network engineer is configuring a Cisco IOS router for IPv6 First Hop Security. The requirement is to prevent rogue DHCPv6 servers from assigning addresses to clients on a VLAN. The engineer has already enabled IPv6 snooping on the VLAN. Which additional feature should be configured to meet this requirement?

Hard
78

A network engineer is troubleshooting an MPLS L3VPN where customer routes are not being advertised between PE routers. The engineer verifies that the VRFs are configured correctly and that MPLS forwarding is operational. Which MP-BGP configuration is required to exchange VPNv4 routes between PE routers?

Hard
79

A network administrator is implementing MPLS Layer 3 VPNs. The customer edge (CE) router is connected to the provider edge (PE) router via a single link and runs OSPF with the PE. The administrator wants to prevent the customer's OSPF routes from being redistributed into the provider's IGP and to keep the customer's OSPF topology separate. Which OSPF process configuration on the PE router achieves this?

Hard
80

A network administrator is troubleshooting an OSPFv3 network. Routers R1 and R2 are directly connected on a point-to-point link. R1 is configured with OSPFv3 area 0, and R2 is configured with OSPFv3 area 1. The administrator notices that no OSPFv3 adjacency forms between them. What is the most likely cause?

Hard
81

A network engineer is configuring a Cisco IOS XE router to act as a DHCP server for a subnet. The router must assign IP addresses from the 192.168.100.0/24 pool, but the first 10 addresses and the last address in the range must be excluded from dynamic assignment. Which command accomplishes this requirement?

Easy
82

A network administrator is configuring a Cisco IOS XE router for MPLS Traffic Engineering (TE). The administrator wants to ensure that the router can signal an MPLS TE tunnel using RSVP. Which protocol must be enabled on the interfaces along the path to reserve bandwidth and distribute labels?

Easy
83

A network administrator is configuring a Cisco IOS router to authenticate users via TACACS+ using a TACACS+ server at 10.1.1.50. The administrator wants to ensure that if the TACACS+ server is unreachable, the router will fall back to using the local username database. Which command set achieves this?

Hard
84

A network engineer is configuring a Cisco IOS XE router as a LISP ITR. The router must encapsulate traffic from local EIDs to remote RLOCs. Which command is required to enable LISP functionality and allow the router to act as an ITR?

Hard
85

A network engineer is configuring MPLS Traffic Engineering (TE) with RSVP-TE on a Cisco IOS XE router. The engineer wants to establish a TE tunnel from Router A to Router D. The path must be explicitly defined to go through Router B and then Router C. The engineer has configured the tunnel interface with the destination and an explicit path. However, the tunnel is not coming up. Which command is required to enable RSVP-TE on the core interfaces of Router A, B, C, and D?

Hard
86

A network engineer is configuring DHCPv6 on a Cisco IOS-XE router. The router must provide IPv6 addresses and other configuration parameters to clients on the LAN. The engineer wants the router to assign addresses using stateless address autoconfiguration (SLAAC) but also provide DNS server information via DHCPv6. Which command set correctly configures the router's LAN interface to achieve this?

Medium
87

A network engineer is troubleshooting a Cisco IOS XE router that is configured for IPv6 First Hop Security on a user VLAN. Hosts report intermittent connectivity, and the engineer suspects that IPv6 Router Advertisement (RA) messages from an unauthorized device are being accepted. Which feature should be enabled to ensure that only RAs from the legitimate router are processed by hosts?

Hard
88

A network administrator is deploying IPv6 First Hop Security (FHS) on a Cisco Catalyst switch to mitigate rogue Router Advertisement (RA) attacks. The switch is running Cisco IOS Software and is configured with the command ipv6 nd raguard policy POLICY1. Which additional step is required to activate RA guard on an interface?

Hard
89

A network engineer is configuring a Cisco IOS XE router to act as a DHCP relay agent. The router receives DHCP discover messages on interface GigabitEthernet0/1 and must forward them to a DHCP server at 10.1.1.100. The engineer configures the command 'ip helper-address 10.1.1.100' on GigabitEthernet0/1. However, the DHCP server is not receiving the requests. Which additional configuration is required to ensure that DHCP relay works correctly?

Hard
90

A network administrator is deploying a DMVPN Phase 3 hub-and-spoke topology using Cisco IOS routers. The hub router is configured with a multipoint GRE (mGRE) interface and NHRP. Spokes are configured with mGRE and NHRP as well. The administrator wants to ensure that spoke-to-spoke traffic flows directly without traversing the hub after initial registration. Which two statements about DMVPN Phase 3 operation are true? (Choose two.)

Hard
91

A network engineer is troubleshooting a DMVPN Phase 3 network. Spoke-to-spoke tunnels are not being established directly; traffic between spokes is going through the hub. The hub is configured with 'ip nhrp redirect' and spokes with 'ip nhrp shortcut'. Which additional configuration is required on the spokes to enable direct spoke-to-spoke communication?

Medium
92

A network engineer is configuring a Cisco IOS XE router to support MPLS L3VPN. The router is a PE device with a VRF named CUSTOMER. The engineer wants to ensure that the PE router can forward traffic for the CUSTOMER VRF using MPLS labels. Which command must be configured on the PE router's core-facing interface to enable MPLS forwarding?

Medium
93

A network engineer is configuring a Cisco router to act as a DHCP relay agent. The DHCP server is located on a different subnet. Which command is required on the router's interface to forward DHCP requests to the server?

Easy
94

A network administrator is configuring a Cisco IOS router to support MPLS Layer 3 VPNs. The router is a PE device that must exchange VPNv4 routes with other PE routers. The administrator has enabled MPLS LDP on the core-facing interfaces and configured BGP with the address-family vpnv4. Which additional configuration is required on the PE router to properly forward MPLS VPN traffic?

Medium
95

A network administrator is configuring a Cisco IOS router to provide first-hop redundancy for a group of hosts on VLAN 10. The design requires that the virtual IP address be 10.1.10.1 and that the router with the highest priority become the active gateway. The administrator has configured the interface with 'standby 10 ip 10.1.10.1' and 'standby 10 priority 150'. Which additional command is required to ensure that the router preempts and becomes the active gateway if it reboots?

Easy
96

A network engineer is configuring a Cisco IOS router to act as a DHCP server for a remote subnet. The router interface connected to that subnet is configured with the address 10.10.10.1/24. The engineer wants the router to assign addresses from the 10.10.10.0/24 range and also provide the default gateway and DNS server information to clients. Which configuration is required on the router to accomplish this?

Medium
97

A network engineer is configuring a Cisco IOS XE router to act as a Dynamic Host Configuration Protocol (DHCP) client on its WAN interface. The service provider requires the router to send a specific client identifier in its DHCP requests. Which command accomplishes this?

Medium
98

A network administrator is troubleshooting an MPLS L3VPN where customer routes are not being propagated between PE routers. The PE routers are Cisco IOS-XE devices running MP-BGP. Which address family must be configured on the PE routers to exchange VPNv4 prefixes?

Hard
99

A network engineer is deploying a DMVPN Phase 3 hub-and-spoke topology. The hub router must dynamically learn spoke-to-spoke routes and allow direct spoke-to-spoke tunnels. Which technology should be implemented on the hub to achieve this?

Medium
100

A network engineer is configuring a Cisco IOS router to support MPLS Traffic Engineering (TE). The engineer has enabled MPLS TE globally and on the interfaces, and has configured a TE tunnel. However, the tunnel is not coming up. The engineer verifies that the IGP (OSPF) is advertising TE information. Which additional configuration is required to establish the TE tunnel?

Medium
101

A network administrator is implementing IPsec VPN between two Cisco routers. The administrator wants to ensure that only specific traffic, defined by an extended access list, is encrypted and sent through the tunnel, while all other traffic is sent unencrypted. Which IPsec configuration element is used to define this traffic?

Hard
102

A network engineer is configuring a Cisco IOS router to use Policy-Based Routing (PBR) to forward traffic from a specific subnet to a next-hop address. The route-map is named PBR_MAP, and the interface is GigabitEthernet0/0. Which command sequence correctly applies the route-map to the interface for incoming packets?

Medium
103

A network engineer is configuring a Cisco IOS XE router as a Dynamic Host Configuration Protocol (DHCP) server for a guest wireless subnet. The router must dynamically allocate addresses from the 192.168.50.0/24 pool, but the first 30 addresses must be reserved for static assignment to access points and controllers. Which command must be issued to prevent the DHCP server from offering those addresses?

Medium
104

A network engineer is troubleshooting a DMVPN Phase 3 deployment on a Cisco IOS XE hub. Spokes use NHRP to register with the hub and have working mGRE tunnels to the hub. The design requires that spoke-to-spoke traffic be sent directly between spokes without transiting the hub's data path. The engineer observes that all spoke-to-spoke packets still traverse the hub even though spoke registration and routing are correct. Which configuration change on the hub is required to enable direct spoke-to-spoke forwarding?

Hard
105

A network engineer is configuring a GRE tunnel between two Cisco IOS routers to transport multicast traffic. The engineer notices that multicast packets are not being forwarded over the tunnel. Which command is required on the tunnel interface to enable multicast forwarding?

Easy
106

A network engineer is configuring a Cisco IOS router to support MPLS Layer 3 VPNs. The engineer needs to enable the provider edge (PE) router to exchange VPNv4 routes with other PE routers. Which protocol is used to distribute VPNv4 routes between PE routers?

Easy

Frequently asked questions

What does the Infrastructure Services domain cover on the 300-410 exam?
Be able to select and apply the exact IOS commands that enable DMVPN Phase 3 spoke-to-spoke forwarding, IPv6 First Hop Security filtering, and TACACS+ AAA with fallback. The single most important thing is knowing which command goes on the hub versus the spoke.
How many questions are in this domain?
This page lists all 106 Infrastructure Services questions in the 300-410 question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
What is the best way to practise this domain?
Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
Can I practise only Infrastructure Services questions?
Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.
enarsi ENARSI infrastructure services Practice Questions