300-410 Mock Exam 72 — 25 Questions

Question 1

Which TWO statements correctly describe the behavior of EIGRP route summarization when using the 'summary-address' command under an interface? (Choose TWO.)

Accepted Answer

A summary route is advertised with the metric equal to the best metric among the component routes.. Option A is correct because when EIGRP advertises a summary route configured with the interface-level summary-address command, the summary inherits the minimum (best) metric among the component routes it covers, so the advertised metric reflects the most favorable path. Option C is correct because EIGRP automatically installs a discard route pointing to Null0 for the summary prefix on the summarizing router, which prevents the router from forwarding traffic for unallocated subnets within the summary and thus avoids routing loops. Option B is incorrect because administrative distance is a local routing-table preference (EIGRP internal is 90) and is not assigned to an advertised summary route by the summary-address command. Option D is incorrect because the interface summary-address command summarizes EIGRP-learned routes, not connected routes, which must be redistributed into EIGRP to be summarized. Option E is incorrect because, by default, the more specific component routes are suppressed from being advertised out the interface where the summary is configured.

Answer

The summary route is automatically assigned an administrative distance of 90 by default.

Answer

The 'summary-address' command also summarizes connected routes that fall within the summary range.

Answer

More specific routes are still advertised out the same interface even after the summary is configured.

Question 2

Which TWO statements about EEM applet debugging and verification are correct? (Choose TWO.)

Accepted Answer

The 'debug event manager action cli' command enables debugging output for CLI actions executed by EEM applets.. Option B is correct because 'debug event manager action cli' specifically turns on debug output for CLI actions that EEM applets execute, letting you see the exact commands run and their results. Option C is correct because 'show event manager history events' displays the recent event history, showing which events fired and triggered applets, which is useful for verifying applet triggering. Option A is wrong because 'show event manager policy available' lists the EEM policies/applets available to be registered on the device, not all configured applets. Option D is wrong because 'show event manager policy active' shows policies that are currently registered and active, not everything that has run recently. Option E is wrong because 'show event manager applet' is not the correct syntax for verifying EEM applets; the valid commands use 'show event manager policy' or 'show event manager history'.

Answer

The command 'show event manager policy available' displays all configured EEM applets on the device.

Answer

The 'show event manager policy active' command shows all applets that are currently running or have run recently.

Answer

The 'show event manager applet' command is not a valid IOS command.

Question 3

A network engineer runs the following command on Router R1:

R1# show crypto isakmp sa
dst             src             state          conn-id slot status
10.1.1.2        10.1.1.1        MM_NO_STATE       1    0    ACTIVE

Based on this output, what is the problem?

Accepted Answer

The IKE phase 1 negotiation has failed; the pre-shared key may be mismatched.. The MM_NO_STATE indicates that the IKE phase 1 negotiation has not progressed past the initial state. This typically means the peer is not responding to the ISAKMP proposals, often due to mismatched pre-shared keys or access-list blocking UDP port 500.

Answer

The IPsec SA is established and working correctly.

Answer

The tunnel is up but no interesting traffic is triggering the IPsec SA.

Answer

The ISAKMP SA is in MM_ACTIVE state, meaning phase 1 is complete.

Question 4

A network engineer runs the following command on Router R1:

R1# show bfd neighbors detail

IPv4 Sessions
NeighborAddr      LD/RD         Int        State         Holdown(mult)  Intf
10.1.1.2          1/3           Gi0/0      Up            3000(3)        Gi0/0

Session state is UP and not using echo function.
OurAddr: 10.1.1.1
Handle: 1
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3
Received MinRxInt: 1000000, Received Multiplier: 3
Holddown (hits): 3000(0)
Rx Count: 100, Tx Count: 100

Based on this output, what is the BFD session's detection time?

Accepted Answer

The detection time is 3000 ms.. The detection time is the holddown timer, which is the negotiated transmit interval multiplied by the multiplier. The negotiated transmit interval is 1000 ms (maximum of local MinTxInt and received MinRxInt), and the multiplier is 3, so the detection time is 3000 ms.

Answer

The detection time is 1000 ms.

Answer

The detection time is 1500 ms.

Answer

The detection time is 9000 ms.

Question 5

Which of the following statements about MPLS L3VPN label operations is true?

Accepted Answer

The ingress PE pushes two labels: the outer IGP label and the inner VPN label.. In MPLS L3VPN, the PE router assigns a per-VRF label (VPN label) for each prefix in the VRF. When forwarding a packet from the CE, the ingress PE pushes an IGP label (for the egress PE) and the VPN label. The egress PE pops the IGP label and uses the VPN label to identify the VRF and forward to the correct CE.

Answer

The egress PE uses the IGP label to determine the VRF.

Answer

The P routers swap the VPN label as they forward the packet.

Answer

The ingress PE pushes only one label (the VPN label) and uses the IP destination for forwarding.

Question 6

Which BGP attribute is considered the highest priority (most preferred) in the BGP best path selection process?

Accepted Answer

Weight. C is correct because the Weight attribute is Cisco-proprietary and is evaluated first in the BGP best path selection process. It has the highest priority, with a higher weight being preferred, and it is local to the router only.

Answer

Local preference

Answer

AS path length

Answer

MED

Question 7

What is the default administrative distance for OSPF routes in Cisco IOS?

Accepted Answer

110. OSPF has a default administrative distance (AD) of 110 in Cisco IOS. This value is used by the router to select the best route when multiple routing protocols provide a route to the same destination, with lower AD values being preferred. OSPF's AD of 110 is higher than that of static routes (1) and EIGRP (90/170), but lower than RIP (120) and IS-IS (115).

Answer

90

Answer

100

Answer

120

Question 8

Consider the following EIGRP configuration on Router R4:

router eigrp 300
 variance 2
 network 172.16.0.0

What is the purpose of the variance command?

Accepted Answer

It allows load balancing over paths with metrics up to twice the best metric.. The variance command in EIGRP allows unequal-cost load balancing by instructing the router to include routes in the routing table whose metric is less than or equal to the best metric multiplied by the variance value. With variance 2, any feasible successor route with a metric up to twice the best metric (i.e., ≤ best_metric × 2) will be installed and used for load balancing, provided it satisfies the feasibility condition (reported distance < feasible distance). Only option B accurately describes this behavior; option C is tempting but less precise because unequal-cost load balancing also requires feasible successors.

Answer

It sets the maximum number of equal-cost paths to 2.

Answer

It enables unequal-cost load balancing with a factor of 2.

Answer

It sets the EIGRP metric weight for delay to 2.

Question 9

Which IP SLA operation type uses ICMP to discover the path (hops) between source and destination?

Accepted Answer

ICMP Path Echo. The ICMP Path Echo operation (type 10) uses ICMP Echo requests with increasing TTL values to trace the path from source to destination, similar to traceroute.

Answer

ICMP Echo

Answer

UDP Jitter

Answer

TCP Connect

Question 10

Which TWO statements about BGP route reflectors are true? (Choose TWO.)

Accepted Answer

A route reflector adds its own cluster ID to the cluster-list attribute when reflecting a route.. Option B is correct because when a route reflector reflects a route, it prepends its cluster ID to the CLUSTER_LIST attribute (creating it if absent), which allows loop prevention within the cluster. Option D is correct because a route reflector reflects routes learned from a client to all other clients and to all non-clients (with the exception of the route's originator), which is the core behavior that eliminates the need for a full IBGP mesh. Option A is wrong because the route reflector does not rewrite NEXT_HOP to its own address; NEXT_HOP is typically preserved (or changed per normal BGP rules), not set to the reflector. Option C is wrong because routes received from a non-client are reflected only to clients and the originator, not to other non-clients. Option E is wrong because the ORIGINATOR_ID is set to the router ID of the router that first injected the route into the IBGP mesh, not to the route reflector's own router ID.

Answer

A route reflector modifies the NEXT_HOP attribute to its own address when reflecting routes.

Answer

A route reflector reflects routes received from a non-client to all other non-clients.

Answer

A route reflector always sets the originator-id attribute to the router ID of the route reflector.

Question 11

An engineer configures CoPP on a router that is a route reflector for iBGP. The policy includes a class-map matching BGP traffic and polices it to 500 pps. After deployment, some iBGP prefixes are missing from the route reflector's table, but the BGP sessions are up. Which is the most likely explanation?

Accepted Answer

CoPP drops BGP update packets from specific clients due to rate limiting, so those prefixes are not learned.. B is correct because CoPP polices BGP traffic to 500 pps, and if BGP update packets from specific iBGP clients exceed this rate, they are dropped. Since BGP keepalives are small and infrequent, the session remains up, but the dropped updates prevent the route reflector from learning certain prefixes, leading to missing routes in the table.

Answer

CoPP drops BGP keepalive packets, causing the session to reset.

Answer

The route reflector is configured to ignore certain prefixes.

Answer

CoPP only affects eBGP, not iBGP.

Question 12

A network engineer runs the following command on Router R2:

R2# show ip route 192.168.10.0
Routing entry for 192.168.10.0/24
  Known via "ospf 1", distance 110, metric 20
  Redistributing via ospf 1
  Last update from 10.0.0.1 on GigabitEthernet0/1, 00:00:10 ago
  Routing Descriptor Blocks:
  * 10.0.0.1, from 10.0.0.1, 00:00:10 ago, via GigabitEthernet0/1
      Route metric is 20, traffic share count is 1

Based on this output, what is the most likely origin of this route?

Accepted Answer

The route is an OSPF external route, likely redistributed.. The metric of 20 is the default metric for OSPF external routes of type E2 (external type 2). The administrative distance of 110 is the default for OSPF routes. This combination indicates the route was redistributed into OSPF from another protocol.

Answer

The route is an OSPF intra-area route.

Answer

The route is an OSPF inter-area route.

Answer

The route is an OSPF NSSA external route.

Question 13

A network engineer is troubleshooting a DHCPv6 prefix delegation issue on router R1 and runs the following command:

R1# debug ipv6 dhcp detail

Output:
 IPv6 DHCP: Received SOLICIT message from FE80::21A:2BFF:FE3C:4D01 on GigabitEthernet0/0
 IPv6 DHCP: Using interface pool DHCP_POOL
 IPv6 DHCP: Sending ADVERTISE message to FE80::21A:2BFF:FE3C:4D01
 IPv6 DHCP: Received REQUEST message from FE80::21A:2BFF:FE3C:4D01
 IPv6 DHCP: Client requests prefix 2001:DB8:1::/48
 IPv6 DHCP: Prefix 2001:DB8:1::/48 not available in pool DHCP_POOL
 IPv6 DHCP: Sending REPLY message with Status Code NoPrefixAvail

What does this output indicate?

Accepted Answer

The DHCPv6 server has a pool configured but the requested prefix is not in that pool or is already allocated.. The debug output shows the client sent a REQUEST for prefix 2001:DB8:1::/48, but the server responded with a REPLY containing the status code NoPrefixAvail. This indicates the requested prefix is either not defined in the DHCP_POOL or has already been allocated to another client, so the server cannot assign it.

Answer

The DHCPv6 client successfully received the prefix 2001:DB8:1::/48.

Answer

The DHCPv6 client is using a relay agent because the SOLICIT was received on a different interface.

Answer

The DHCPv6 server is configured with a stateless configuration because it sent an ADVERTISE without a prefix.

Question 14

In Policy-Based Routing (PBR), what is the default action for packets that do not match any route-map sequence?

Accepted Answer

They are forwarded using the normal routing table.. Route-maps have an implicit deny at the end. For PBR, if a packet does not match any permit sequence, it is not policy-routed and is forwarded using the normal routing table.

Answer

They are dropped.

Answer

They are forwarded using the default route.

Answer

They are sent to the next-hop specified in the last sequence.

Question 15

Which of the following is true regarding the placement of an IPv4 ACL to filter traffic between two internal subnets?

Accepted Answer

Standard ACLs should be placed closest to the destination.. Standard ACLs filter based solely on the source IP address and lack the granularity to distinguish between different destination subnets. Placing a standard ACL closest to the destination ensures that traffic is filtered only after it has reached the target subnet, preventing the ACL from inadvertently blocking traffic to other destinations that share the same source. This placement aligns with the Cisco best practice of placing standard ACLs near the destination to minimize unintended filtering.

Answer

Standard ACLs should be placed closest to the source.

Answer

Extended ACLs should be placed closest to the destination.

Answer

Placement does not affect ACL functionality.

Question 16

What is the default BFD multiplier (detection time multiplier) on Cisco IOS-XE?

Accepted Answer

3. The default BFD multiplier is 3, meaning the detection time is 3 times the negotiated hello interval.

Answer

1

Answer

2

Answer

4

Question 17

A network engineer runs the following command on Router R1:

R1# show ipv6 snooping policy
Interface                      Policy                      Role            State
Gi0/0/0                        GUARD_POLICY                device-guard    ACTIVE
Gi0/0/1                        GUARD_POLICY                device-guard    ACTIVE
Gi0/0/2                        (default)                   host            ACTIVE

Based on this output, which statement is correct?

Accepted Answer

Interface Gi0/0/2 is not protected by the custom guard policy and may be vulnerable to spoofing attacks.. The output shows that Gi0/0/2 is using the default policy with a role of 'host', meaning it is not protected by the custom GUARD_POLICY. The device-guard feature, part of IPv6 First Hop Security, applies only to interfaces with a custom policy; a default policy does not enforce spoofing protection, leaving the interface vulnerable to attacks like rogue RA or ND spoofing.

Answer

Interface Gi0/0/2 is protected by the GUARD_POLICY policy.

Answer

All interfaces are equally protected by the same policy.

Answer

The role 'host' means Gi0/0/2 is acting as a device-guard.

Question 18

A network engineer runs the following command to verify redistribution with route-maps:

R1# show ip route 10.10.10.0 255.255.255.0
Routing entry for 10.10.10.0/24
  Known via "eigrp 100", distance 170, metric 2560002816
  Tag 100, type internal
  Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:45 ago
  Routing Descriptor Blocks:
  * 10.1.1.2, from 10.1.1.2, 00:00:45 ago, via GigabitEthernet0/0
      Route metric is 2560002816, traffic share count is 1
      Total delay is 2000 microseconds, minimum bandwidth is 100000 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 1/255, Hops 1

What does the 'Tag 100' indicate?

Accepted Answer

The route has a tag of 100, likely set by a route-map during redistribution.. The 'Tag 100' indicates that a route-map applied during redistribution set the tag to 100. Route tags are often used for filtering or administrative purposes during redistribution.

Answer

The route was originated by EIGRP autonomous system 100.

Answer

The route is internal to EIGRP and has a metric of 100.

Answer

The route is from a BGP AS 100.

Question 19

A network engineer runs the following command to troubleshoot an IPv4 Access Control Lists issue:

R1# show access-lists 120
Extended IP access list 120
    10 permit tcp 192.168.1.0 0.0.0.255 any eq 80
    20 permit tcp 192.168.2.0 0.0.0.255 any eq 443
    30 deny ip any any log

What does this output indicate?

Accepted Answer

The ACL permits HTTP traffic from 192.168.1.0/24 and HTTPS traffic from 192.168.2.0/24, and denies all other traffic with logging.. The output shows an extended ACL with two permit statements: the first permits TCP traffic from 192.168.1.0/24 to any destination on port 80 (HTTP), and the second permits TCP traffic from 192.168.2.0/24 to any destination on port 443 (HTTPS). The final deny ip any any log statement explicitly denies all other IP traffic and logs matches, which is standard practice for ACL troubleshooting. Therefore, option A correctly describes the ACL's behavior.

Answer

The ACL permits all traffic from 192.168.1.0/24 and 192.168.2.0/24.

Answer

The ACL denies all traffic from 192.168.1.0/24 and 192.168.2.0/24.

Answer

The ACL is applied inbound on an interface and is blocking all traffic.

Question 20

A large enterprise network is experiencing intermittent reachability to a subnet 10.1.1.0/24 from the rest of the network. Router R1 has the following relevant configuration:
router eigrp 100
 redistribute ospf 1 metric 10000 100 255 1 1500
!
router ospf 1
 redistribute eigrp 100 subnets
 summary-address 10.0.0.0 255.255.0.0
!
interface GigabitEthernet0/0
 ip summary-address eigrp 100 10.0.0.0 255.255.0.0 5

Router R2 shows:
R2# show ip route 10.1.1.0
Routing entry for 10.0.0.0/16, supernet
  Known via "eigrp 100", distance 90, metric 128256
  Redistributing via eigrp 100
  Last update from 10.10.10.1 on GigabitEthernet0/1

What is the root cause?

Accepted Answer

The OSPF summary-address command on R1 is blocking the redistribution of the specific /24 route.. The issue is that R1 has both an OSPF summary-address and an EIGRP interface summary-address, causing the more specific /24 route to be suppressed by the /16 summary. The EIGRP summary-address command on the interface creates a null0 summary route, and the OSPF redistribution of the EIGRP summary further aggregates, losing the specific prefix. The fix is to remove the interface summary-address or adjust the summary to include the specific subnet.

Answer

The EIGRP metric values are too high, causing the route to be unreachable.

Answer

The redistribute ospf command under EIGRP is missing the subnets keyword.

Answer

The route is being filtered by a distribute-list on R2.