300-410 Practice Test 24 — 15 Questions

Question 1

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?

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

Accepted Answer

ip helper-address <server-ip>. The ip helper-address command on an interface enables the router to forward DHCP broadcast requests to a specified DHCP server on another subnet. This is essential when clients and the DHCP server are on different broadcast domains. The command also forwards other UDP broadcasts by default, but DHCP relay is the primary use case here.

Answer

ip forward-protocol udp 67

Answer

ip dhcp pool <name>

Answer

ip dhcp relay <server-ip>

Question 2

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?

Accepted Answer

The router will not assign addresses 10.10.10.1 through 10.10.10.20 to DHCP clients, but those addresses can still be manually configured on other devices.. The excluded-address command removes a range of addresses from dynamic DHCP allocation, ensuring they are not offered to clients. Those addresses can still be statically configured on other devices, such as routers, switches, or servers. This prevents IP address conflicts while allowing manual assignment where needed.

Answer

The router will reserve addresses 10.10.10.1 through 10.10.10.20 for DHCP clients only, preventing static assignment on other devices.

Answer

The router will exclude the entire 10.10.10.0 /24 subnet from DHCP, so no addresses will be assigned from that pool.

Answer

The router will assign addresses 10.10.10.1 through 10.10.10.20 only to clients that match a specific MAC address in a manual binding.

Question 3

A network engineer runs the following command on Router R1:

R1# show ip nat translations
Pro Inside global      Inside local       Outside local      Outside global
--- 192.0.2.10         10.0.0.10          ---                ---

R1# show ip nat statistics
Total active translations: 1 (1 static, 0 dynamic; 0 extended)
Outside interfaces: GigabitEthernet0/1
Inside interfaces: GigabitEthernet0/0
Hits: 5  Misses: 0
CEF Translated packets: 5, CEF Punted packets: 0
Expired translations: 0

Based on this output, which statement is correct?

Accepted Answer

Static NAT is configured for host 10.0.0.10 to 192.0.2.10.. The output shows a single static NAT translation from inside local address 10.0.0.10 to inside global address 192.0.2.10. The 'show ip nat statistics' confirms '1 static' translation with no dynamic entries, and the NAT table lacks a port number, indicating a one-to-one static mapping rather than PAT. Therefore, static NAT is correctly configured for host 10.0.0.10 to 192.0.2.10.

Answer

Dynamic NAT is configured with overload.

Answer

The NAT pool is exhausted.

Answer

PAT is translating multiple hosts to the same global address.

Question 4

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?

Accepted Answer

Configure the OSPF process within the VRF and do not redistribute it into the provider's OSPF process.. To keep the customer's OSPF separate, the PE router runs a VRF-specific OSPF process that is not redistributed into the provider's global OSPF. Customer routes are instead redistributed into MP-BGP for VPNv4 transport. This ensures isolation and prevents the customer's routes from entering the provider's IGP.

Answer

Configure a separate OSPF process for the customer VRF and use distribute-list to filter routes.

Answer

Configure OSPF with the capability vrf-lite command under the routing process.

Answer

Configure OSPF with the domain-id command to match the provider's OSPF domain.

Question 5

A network engineer is troubleshooting NAT for a VoIP phone that uses SIP. The phone is at 192.168.2.10, and the router performs PAT to the outside interface 198.51.100.1. The phone can register with the SIP server, but calls fail after 30 seconds. The engineer notices that the SIP signaling includes the phone's private IP in the SDP body. What is the most likely cause?

Accepted Answer

The router's SIP ALG is disabled, so the private IP in the SDP is not translated.. The SIP signaling includes the phone's private IP in the SDP body, which is used for media negotiation. When the router's SIP Application Layer Gateway (ALG) is disabled, it does not inspect and translate the private IP addresses embedded in the SDP payload. As a result, the SIP server sends media (RTP) to the private IP 192.168.2.10, which is unreachable from outside, causing the call to fail after the initial registration and signaling succeed.

Answer

The PAT port range is exhausted.

Answer

The phone's default gateway is misconfigured.

Answer

The outside interface has a firewall blocking UDP ports.

Question 6

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?

Accepted Answer

Enable NHRP redirect on the hub.. In DMVPN Phase 3, direct spoke-to-spoke communication is achieved by combining NHRP redirect on the hub and NHRP shortcut on the spokes. The hub uses NHRP redirect to inform a spoke that a better path exists to another spoke. The spoke then uses NHRP shortcut to resolve the destination and build a direct tunnel. Without redirect on the hub, spokes never learn about the direct path and continue to forward traffic through the hub, defeating the purpose of Phase 3.

Answer

Enable NHRP shortcut on the hub.

Answer

Set the tunnel mode to multipoint GRE on the hub.

Answer

Configure the hub as a route reflector for BGP.

Question 7

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?

Accepted Answer

The route targets are not properly configured for import/export.. In MPLS L3VPN, route targets are extended BGP communities that determine which VRFs import and export routes. For a route to be installed in a remote VRF, the export RT attached to the route by the originating PE must match an import RT configured on the receiving PE's VRF. If they do not match, the route is discarded. This is a frequent issue when VRFs are newly configured or when RTs are changed. Verifying RT configuration on both PEs is essential.

Answer

The MPLS LDP session between the PEs is down.

Answer

The PE routers are not configured with unique route distinguishers.

Answer

The BGP session is not configured with the correct address-family.

Question 8

A network engineer runs the following command to troubleshoot a Route Summarization issue:

R1# debug ip routing
IP: route table change: 10.0.0.0/16 via 10.1.1.2, Serial0/0/0, distance 90, metric 128576
IP: route table change: 10.0.1.0/24 via 10.1.1.2, Serial0/0/0, distance 90, metric 128576
IP: route table change: 10.0.2.0/24 via 10.1.1.2, Serial0/0/0, distance 90, metric 128576

What does this output indicate?

Accepted Answer

Both the summary route 10.0.0.0/16 and more specific /24 routes are being installed, which could indicate that summarization is not properly filtering the specific routes.. The debug output shows that multiple routes (a /16 and two /24s) are being installed into the routing table via the same next hop. This indicates that both the summary route and more specific routes are present, which may be a sign of inconsistent summarization or a leak of more specific routes.

Answer

Only the summary route is being installed, and the /24 routes are being ignored.

Answer

The summary route is being replaced by the more specific routes.

Answer

The routes are being learned via different routing protocols.

Question 9

Which TWO configuration steps are required to implement Policy-Based Routing (PBR) on a Cisco router? (Choose TWO.)

Accepted Answer

Create a route-map with match and set commands.. Option A is correct because PBR is defined inside a route-map, where 'match' statements identify the traffic (typically via an ACL or prefix-list) and 'set' statements define the forwarding action such as 'set ip next-hop' or 'set interface'. Option B is correct because the route-map must be attached to the ingress interface with the interface-level command 'ip policy route-map <name>' for PBR to take effect on transit traffic. Option C is not required as a separate step because the ACL is referenced within the route-map's match statement rather than configured as an independent mandatory configuration element. Option D is not required because Cisco Express Forwarding is enabled by default on modern Cisco IOS platforms and is not a PBR-specific configuration step. Option E is incorrect for this scenario because 'ip local policy route-map' applies PBR to router-generated (locally sourced) traffic, not to traffic being routed through an interface.

Answer

Configure an access-list to match the traffic.

Answer

Enable CEF globally.

Answer

Use the 'ip local policy route-map' command.

Question 10

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?

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

Accepted Answer

BGP with the VPNv4 address family. MP-BGP with the VPNv4 address family is the standard protocol for exchanging VPNv4 routes between PE routers in MPLS L3VPN deployments. It carries the necessary extended communities (route targets, route distinguishers) to support multiple VPNs. Other protocols like OSPF, LDP, and RSVP-TE serve different purposes and cannot distribute VPNv4 routes.

Answer

RSVP-TE

Answer

OSPFv2

Answer

LDP

Question 11

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?

Accepted Answer

Apply the service policy to the control-plane interface.. CoPP is implemented by creating a traffic class that matches control-plane traffic, defining a policy map with a policer, and attaching the policy to the control-plane interface. This interface is a virtual interface that represents traffic destined to the route processor. Applying the policy elsewhere, such as physical interfaces, would not selectively target control-plane traffic and could impact transit traffic.

Answer

Apply the service policy to all physical interfaces.

Answer

Configure an ACL to match ICMP echo requests and apply it inbound on the WAN interface.

Answer

Enable IP source guard on all interfaces.

Question 12

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.)

Accepted Answer

Route targets configured under VRFs. MPLS Layer 3 VPNs rely on MP-BGP with the VPNv4 address family to exchange customer routes between PE routers. Route targets, implemented as extended BGP communities, are used to control import and export of these routes into VRFs. Together, they enable the PE routers to maintain separate routing tables and forward customer traffic correctly across the shared MPLS core.

Answer

OSPF as the PE-CE routing protocol

Answer

RSVP-TE for traffic engineering

Answer

LDP for label distribution

Question 13

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?

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

Accepted Answer

ip helper-address 10.1.1.100. To configure a Cisco IOS router as a DHCP relay agent, the ip helper-address command must be applied to the interface where DHCP broadcasts are received. This command forwards the broadcasts as unicast packets to the specified DHCP server. It is the standard and required configuration for this functionality.

Answer

ip dhcp relay 10.1.1.100

Answer

ip forward-protocol udp 67

Answer

ip dhcp server 10.1.1.100

Question 14

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?

Accepted Answer

ip route 0.0.0.0 0.0.0.0 203.0.113.1. The NAT configuration correctly translates inside addresses to the outside interface address using PAT. However, the router lacks a default route to reach the Internet. Without a default route pointing to the ISP's next-hop address, the router cannot forward packets beyond its directly connected networks, so inside hosts cannot access external destinations.

Answer

ip nat inside source list 1 pool overload

Answer

ip nat inside source static 192.168.1.0 203.0.113.5

Answer

ip nat pool overload 203.0.113.5 203.0.113.5 netmask 255.255.255.0

Question 15

What is the default authentication type for NHRP in a DMVPN configuration?

Accepted Answer

No authentication. By default, NHRP does not use any authentication. Authentication can be configured using the 'ip nhrp authentication' command, but it is disabled by default.

Answer

Plaintext password

Answer

MD5 hash

Answer

IPsec