300-410 Practice Test 41 — 15 Questions

Question 1

A network engineer runs the following command on Router R6:

R6# show ip route 10.0.0.0
Routing entry for 10.0.0.0/8
  Known via "eigrp 100", distance 90, metric 28160
  Redistributing via eigrp 100
  Last update from 192.168.1.1 on GigabitEthernet0/0, 00:00:10 ago
  Routing Descriptor Blocks:
  * 192.168.1.1, from 192.168.1.1, 00:00:10 ago, via GigabitEthernet0/0
      Route metric is 28160, traffic share count is 1

Additionally, an OSPF route for the same prefix is learned with distance 110. Which route will be installed in the routing table?

Accepted Answer

The EIGRP route will be installed because it has a lower administrative distance.. EIGRP internal routes have a default administrative distance of 90, which is lower than OSPF's default distance of 110. Therefore, the EIGRP route will be preferred and installed in the routing table.

Answer

The OSPF route will be installed because it has a lower metric.

Answer

Both routes will be installed for load balancing.

Answer

Neither route will be installed due to a conflict.

Question 2

A router configured as a DHCPv6 relay agent is not forwarding DHCPv6 requests from clients to the server. The relay interface has 'ipv6 dhcp relay destination' configured. Clients are on a different VLAN. Which is the most likely explanation?

Accepted Answer

The relay destination is configured on the client-facing interface; it should be on the server-facing interface.. The 'ipv6 dhcp relay destination' command must be configured on the interface facing the DHCPv6 clients, not the server-facing interface. This command instructs the router to intercept DHCPv6 messages arriving on that interface and forward them as relay-forward messages to the specified DHCPv6 server. Placing it on the server-facing interface would cause the router to attempt relaying on the wrong interface, so client requests on the client-facing VLAN are never intercepted or forwarded.

Answer

The DHCPv6 server is not reachable via the relay agent's routing table.

Answer

The relay agent must have 'ipv6 dhcp server' configured to act as a server.

Answer

The clients are using DHCPv4, not DHCPv6.

Question 3

What is missing from this RSPAN configuration on a switch?

monitor session 1 source interface GigabitEthernet1/0/1 both
monitor session 1 destination remote vlan 100

Assume VLAN 100 exists but is not configured as an RSPAN VLAN.

Accepted Answer

The 'remote-span' command under VLAN 100.. For RSPAN to work, the VLAN used as the destination remote VLAN must be configured with the 'remote-span' command. Without it, the session will not function correctly.

Answer

An IP address on the destination interface.

Answer

A destination interface on the source switch.

Answer

The 'no shutdown' command on VLAN 100.

Question 4

An EIGRP network is experiencing a stuck-in-active (SIA) condition for a route 192.168.1.0/24. R1 has the following configuration: router eigrp 100 network 10.0.0.0 distribute-list prefix PL-FILTER in. R2 shows: 'show ip eigrp topology 192.168.1.0/24' is in active state, and 'show ip eigrp events' shows that R1 sent a query but never received a reply. R1's prefix-list PL-FILTER permits only 10.0.0.0/8. What is the root cause?

Accepted Answer

The distribute-list inbound on R1 filters the EIGRP query for 192.168.1.0/24, preventing R1 from replying and causing SIA on R2.. The distribute-list prefix PL-FILTER in on R1 filters incoming routes, but it also affects queries. When R2 sends a query for 192.168.1.0/24, R1 receives it but the distribute-list filters the query (since the prefix is not permitted), so R1 does not process it and does not send a reply. This causes R2 to wait indefinitely for a reply, leading to an SIA condition. The distribute-list should be applied outbound or should permit the necessary prefixes to allow queries to be processed.

Answer

The EIGRP K-values are mismatched between R1 and R2.

Answer

The route 192.168.1.0/24 is not in R1's topology table, so it cannot reply.

Answer

The EIGRP timers on R1 are set too high, causing a delay in reply.

Question 5

A network engineer runs the following command to troubleshoot a VRF-Lite IPsec issue:

R1# show crypto ipsec transform-set vrf CUSTOMER_H

Output:
Transform set combined: { esp-aes 256 esp-sha-hmac }
   will negotiate = { Tunnel,  }

What does this output indicate?

Accepted Answer

The transform set uses ESP with AES 256 and SHA-HMAC in tunnel mode.. The 'show crypto ipsec transform-set vrf' command displays the IPsec transform set for a specific VRF. The output shows a transform set named 'combined' that uses ESP with AES 256-bit encryption and SHA-HMAC authentication. It will negotiate a tunnel mode (as opposed to transport mode).

Answer

The transform set uses ESP with AES 256 and SHA-HMAC in transport mode.

Answer

The transform set uses AH with AES 256 and MD5.

Answer

The transform set does not specify any encryption or authentication.

Question 6

R1 and R2 have an IPsec VPN tunnel between their physical interfaces. They are running OSPF over the tunnel interface. R1's show ip ospf neighbor shows R2 as FULL, but R1's show ip route ospf does not include any routes from R2. R2's show ip route ospf shows routes from R1. What is the root cause?

Accepted Answer

The OSPF cost on R1's tunnel interface is set to 65535, preventing route installation.. When the OSPF cost on R1's tunnel interface is set to 65535, OSPF considers the route unreachable because the maximum OSPF cost for route installation is 65534 (per RFC 2328). Routes with cost 65535 are not installed in the routing table, even though the neighbor state is FULL. This explains why R1 sees R2 as FULL but has no OSPF routes, while R2 (with a normal cost) installs routes from R1.

Answer

OSPF network type mismatch: R1 uses broadcast, R2 uses point-to-point.

Answer

R1 has a distribute-list in filtering OSPF routes.

Answer

The IPsec tunnel is only encrypting unicast traffic, not OSPF multicast.

Question 7

Router R1 is configured with ip nat inside source list 100 interface GigabitEthernet0/1 overload. Users report that some websites load slowly or partially. Router R1 shows: show ip nat statistics: Total active translations: 65535 (0 static, 65535 dynamic; 65535 extended). The NAT pool is exhausted. What is the root cause?

Accepted Answer

Reduce the NAT timeout values using ip nat translation timeout and ip nat translation tcp-timeout.. The NAT pool is exhausted with 65535 active translations, which is the maximum number of PAT entries (port numbers) available for a single public IP. This causes new or existing sessions to fail or load partially. Reducing NAT timeout values (e.g., ip nat translation timeout and ip nat translation tcp-timeout) frees port mappings faster, alleviating the exhaustion without requiring additional public IPs.

Answer

Increase the access-list 100 to include more internal hosts.

Answer

Change the NAT to use a pool of public IPs instead of overload.

Answer

Clear the NAT table with clear ip nat translation * periodically.

Question 8

A DMVPN Phase 3 network with MPLS LDP configured on the tunnel interfaces experiences label distribution failures. R1 (hub) and R2 (spoke) have LDP neighborships established, but R2 is not receiving labels for prefixes behind R3 (another spoke). What is the root cause?

Accepted Answer

LDP is not enabled on the tunnel interface of R3, so R2 cannot receive labels for prefixes behind R3.. In DMVPN Phase 3, the tunnel interface is a multipoint interface. LDP uses the primary IP address of the interface for neighbor discovery. If the tunnel interface is configured with 'ip mtu' or 'ip tcp adjust-mss' that differs between routers, or if the LDP hello packets are not reaching the other routers due to NHRP resolution issues, label distribution may fail. The most common cause is that LDP is not enabled on the tunnel interface or the label space is not correctly configured for DMVPN.

Answer

R2 has a higher LDP router ID, causing it to become the LDP session initiator.

Answer

NHRP is not resolving R3's tunnel IP to its physical IP, preventing LDP hello packets from reaching R3.

Answer

The MPLS label range on R2 is exhausted, preventing new label bindings.

Question 9

A network engineer is troubleshooting a router that is experiencing high CPU utilization. The engineer checks the process list and sees that the 'EEM Server' process is consuming a significant amount of CPU. The engineer reviews the EEM configuration and finds multiple applets that are triggered by syslog events. What should the engineer do first to reduce CPU utilization?

Accepted Answer

Use the 'show event manager statistics' command to see which applets are triggered most often.. High CPU from EEM is often due to excessive syslog triggers. The engineer should first identify which applets are being triggered most frequently and either optimize their conditions or reduce the number of applets.

Answer

Disable all EEM applets.

Answer

Increase the router's CPU priority for the EEM process.

Answer

Change the syslog trigger to use a less frequent pattern.

Question 10

Which THREE symptoms indicate that an Embedded Event Manager (EEM) applet configured to send a syslog message upon interface down has failed to execute? (Choose THREE.)

Accepted Answer

No custom syslog message appears on the console or in the log buffer when the interface goes down.. If the applet fails, no custom syslog is generated, the 'show event manager history events' will not show the trigger, and the 'show event manager policy active' may show the policy but with a non-zero failure count. The other options either describe normal behavior or unrelated issues.

Answer

The interface goes down and the router generates a default syslog message like '%LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down'.

Answer

The 'show event manager environment' output shows the variable '_event_type' as 'none'.

Question 11

A network engineer runs the following command to troubleshoot a VRF-Lite DMVPN issue:

R1# show ip nhrp vrf CUSTOMER_G detail

Output:
10.6.6.1/32 via 10.6.6.1, Tunnel0 created 00:01:00, expire 01:59:00
  Type: dynamic, Flags: used
  NBMA address: 192.168.1.1
  (no-socket)
  Registration handle: 0x00000001
  Cache entries: 1

What does this output indicate?

Accepted Answer

The NHRP mapping for 10.6.6.1 is dynamic, with NBMA address 192.168.1.1, and is actively used.. The 'show ip nhrp vrf detail' command displays NHRP cache entries for a specific VRF. The output shows a dynamic NHRP mapping for destination 10.6.6.1/32, with NBMA address 192.168.1.1, learned via Tunnel0. The entry was created 1 minute ago and will expire in 1 hour 59 minutes. The 'used' flag indicates the mapping is actively being used.

Answer

The NHRP mapping is static and was manually configured.

Answer

The NHRP mapping has expired and needs to be refreshed.

Answer

The NHRP mapping is for a multicast group address.

Question 12

Which TWO commands can be used to troubleshoot EIGRP route redistribution issues when routes are not appearing in the routing table? (Choose TWO.)

Accepted Answer

show ip protocols. The 'show ip protocols' command (A) is correct because it displays the routing protocol configuration, including redistribution settings such as the metric, route map, and which protocols are being redistributed. When EIGRP routes are missing from the routing table, this command helps verify that redistribution is correctly configured and active, which is a primary troubleshooting step for redistribution issues.

Answer

show ip route

Answer

show ip ospf database

Answer

debug ip routing

Question 13

What is the default BGP update timer interval in Cisco IOS-XE?

Accepted Answer

30 seconds for eBGP, 0 seconds for iBGP. BGP does not have a fixed update timer like RIP; updates are triggered by changes, but the default minimum route advertisement interval (MRAI) is 30 seconds for eBGP and 0 seconds for iBGP.

Answer

60 seconds for both eBGP and iBGP

Answer

5 seconds for eBGP, 15 seconds for iBGP

Answer

0 seconds for eBGP, 30 seconds for iBGP

Question 14

What is the default BGP keepalive timer value in Cisco IOS-XE?

Accepted Answer

60 seconds. The default BGP keepalive timer is 60 seconds, as defined in RFC 4271 and implemented in Cisco IOS-XE.

Answer

30 seconds

Answer

90 seconds

Answer

180 seconds

Question 15

An engineer is troubleshooting BGP convergence issues. Which THREE commands can be used to verify BGP path selection and best path criteria? (Choose THREE.)

Accepted Answer

show ip bgp . BGP path selection can be verified using 'show ip bgp ' to see the best path and all paths, 'show ip bgp neighbors routes' to see received routes, and 'show ip bgp' to see the BGP table summary. 'show ip route bgp' shows only the RIB, not the BGP decision process. 'show ip bgp community' filters by community but does not show path selection details.

Answer

show ip route bgp

Answer

show ip bgp community <community>