300-410 Practice Test 28 — 15 Questions

Question 1

A DMVPN network with EIGRP as the routing protocol is experiencing spoke-to-spoke tunnel failures. Spoke routers R1 and R2 are both connected to hub R3. R1 shows: 'show ip nhrp' lists R2's NBMA address, but 'show ip eigrp neighbors' does not show R2. R1's configuration: interface Tunnel0 ip nhrp network-id 1 ip nhrp nhs 10.0.0.3. What is the root cause?

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

Accepted Answer

R1 has no EIGRP configuration on the tunnel interface, so it does not send hellos over the tunnel.. R1's 'show ip nhrp' lists R2's NBMA address, confirming NHRP phase 2/3 spoke-to-spoke resolution is working. However, 'show ip eigrp neighbors' does not show R2, indicating EIGRP adjacency is not established. Since R1's tunnel interface lacks EIGRP configuration (no 'ip eigrp <as-number>' under Tunnel0), it does not send EIGRP hellos over the tunnel, preventing neighbor formation even though NHRP can dynamically map spoke addresses.

Answer

R2's NHRP registration is incomplete, so R1 cannot reach R2's NBMA address.

Answer

The hub R3 is not configured to forward EIGRP packets between spokes.

Answer

R1's tunnel interface has an ACL that blocks EIGRP packets.

Question 2

A network engineer runs the following command on Router R1:

R1# show ipv6 mld interface tunnel 0

Tunnel0 is up, line protocol is up
  Internet address is FE80::1
  MLD is enabled on interface
  Current MLD version is 2
  MLD query interval is 125 seconds
  MLD querier timeout is 255 seconds
  MLD max query response time is 10 seconds
  Last member query response interval is 1 second
  MLD activity: 0 joins, 0 leaves
  MLD querying router is FE80::1 (this system)

Based on this output, what can be concluded?

Accepted Answer

There are no multicast listeners on this tunnel interface.. The output shows 'MLD activity: 0 joins, 0 leaves', indicating that no multicast listeners have joined any multicast group on this tunnel interface. Since MLD (Multicast Listener Discovery) is used to track group membership, zero joins means there are no active listeners. Therefore, option C is correct.

Answer

MLD is disabled on this interface.

Answer

This router is not the MLD querier.

Answer

MLD version 1 is in use.

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_ACTIVE      1       0     ACTIVE
10.1.1.3        10.1.1.1        MM_ACTIVE      2       0     ACTIVE

Based on this output, which statement is correct?

Accepted Answer

IKE phase 1 is complete for both peers.. The show crypto isakmp sa command shows IKE phase 1 security associations. The state MM_ACTIVE indicates that IKE phase 1 is complete and active. The output shows two active SAs with the local router (10.1.1.1) and two remote peers (10.1.1.2 and 10.1.1.3).

Answer

IKE phase 2 is complete for both peers.

Answer

The IPsec tunnels are established.

Answer

The peers are not responding.

Question 4

Which BGP attribute is considered 'well-known mandatory' and must be present in all BGP update messages?

Accepted Answer

AS_PATH. The AS_PATH attribute is well-known mandatory, meaning it must be included in all BGP updates. Other well-known mandatory attributes include NEXT_HOP and ORIGIN.

Answer

LOCAL_PREF

Answer

MED

Answer

COMMUNITY

Question 5

What is the default ERSPAN ID range on Cisco IOS-XE devices?

Accepted Answer

1 to 1023. ERSPAN sessions use an ID from 1 to 1023 (or 1 to 256 on some platforms) to identify the session. The default is 1 if not specified.

Answer

1 to 256

Answer

1 to 4096

Answer

1 to 65535

Question 6

Which of the following is true about the SPAN source interface configuration?

Accepted Answer

By default, only ingress traffic is monitored.. A SPAN source interface can be configured to monitor both ingress and egress traffic, or either direction. By default, only ingress traffic is monitored if no direction is specified.

Answer

By default, both ingress and egress traffic are monitored.

Answer

By default, only egress traffic is monitored.

Answer

The direction must always be specified; there is no default.

Question 7

What is the default NHRP holdtime value on a Cisco router?

Accepted Answer

3600 seconds. The default NHRP holdtime is 3600 seconds (1 hour). This value can be modified with the 'ip nhrp holdtime' command.

Answer

1800 seconds

Answer

7200 seconds

Answer

600 seconds

Question 8

What is the default OSPF network type for a tunnel interface configured with 'tunnel mode gre multipoint'?

Accepted Answer

Broadcast. By default, a multipoint GRE tunnel interface uses the broadcast network type, which requires DR/BDR elections.

Answer

Point-to-multipoint

Answer

Point-to-point

Answer

Non-broadcast

Question 9

Which TWO commands would a network engineer use to verify the NHRP registration status of a spoke router in a DMVPN Phase 2 network? (Choose TWO.)

Accepted Answer

show dmvpn. The 'show dmvpn' command displays the current DMVPN tunnel status, including the NHRP registration state of each peer. The 'show ip nhrp' command shows the NHRP cache entries, which include the registration status and mapping information. The other commands either do not show NHRP registration details or are for different purposes.

Answer

show crypto isakmp sa

Answer

show ip route

Answer

show ip eigrp neighbors

Question 10

Which statement about RSPAN source session is correct?

Accepted Answer

The RSPAN source session must specify a destination RSPAN VLAN.. An RSPAN source session mirrors traffic from source ports to an RSPAN VLAN. The source session can monitor a single VLAN or a set of ports, but not both in the same session. The destination is always the RSPAN VLAN.

Answer

The RSPAN source session can send mirrored traffic to multiple RSPAN VLANs simultaneously.

Answer

The RSPAN source session can monitor both a VLAN and individual ports at the same time.

Answer

The RSPAN source session can use a physical interface as a destination instead of a VLAN.

Question 11

What is the default ERSPAN encapsulation type on Cisco IOS-XE devices?

Accepted Answer

ERSPAN Type II. ERSPAN defaults to Type II encapsulation, which uses a 4-byte GRE header with a 4-byte ERSPAN header (8 bytes total). Type III is optional and requires explicit configuration.

Answer

ERSPAN Type I

Answer

ERSPAN Type III

Answer

ERSPAN Type IV

Question 12

A DMVPN Phase 3 network uses BGP for routing between hubs and spokes. R1 (hub) and R2 (spoke) have an eBGP peering. R2 advertises a prefix 192.168.1.0/24 to R1. R3 (another spoke) receives this prefix via R1 but with a higher local preference than expected, causing R3 to prefer the path through R1 even though a direct spoke-to-spoke tunnel exists. What is the root cause?

Accepted Answer

R1 has a route-map that sets local preference to 200 for prefixes received from R2, causing R3 to prefer the path through R1 over the direct path.. BGP local preference is manipulated on the hub (R1) using route-maps or policy, causing the prefix to have a higher local preference when advertised to other spokes. This overrides the normal BGP path selection and forces traffic through the hub, even if a direct spoke-to-spoke tunnel is available.

Answer

R3 has a static route pointing to R1 for 192.168.1.0/24, overriding BGP.

Answer

NHRP redirect is disabled on R1, preventing spoke-to-spoke tunnel establishment.

Answer

R2 is advertising the prefix with a MED of 0, causing R3 to prefer the path through R1.

Question 13

What is the default MTU size for ERSPAN encapsulated packets on Cisco IOS-XE?

Accepted Answer

The ERSPAN packet inherits the interface MTU, with no separate default.. ERSPAN adds a GRE header (4 bytes) and an ERSPAN header (4 bytes for Type II) to the original packet. The default system MTU is 1500 bytes, but the ERSPAN packet may exceed this; however, the default MTU for the ERSPAN session itself is not explicitly set—it inherits the interface MTU. There is no separate default ERSPAN MTU; the question tests understanding that ERSPAN adds 8 bytes overhead.

Answer

1500 bytes

Answer

1492 bytes

Answer

The default ERSPAN MTU is 1518 bytes.

Question 14

Which TWO statements about the limitations of local SPAN are correct? (Choose TWO.)

Accepted Answer

A local SPAN session can only monitor traffic on the same switch where the session is configured.. Local SPAN has several restrictions: it cannot send traffic across Layer 3 boundaries, it can only use interfaces on the same switch, and it has limitations on the number of sessions and the types of traffic that can be mirrored (e.g., control plane traffic is not included).

Answer

A local SPAN destination port can be a routed port or a switchport in trunk mode.

Answer

A local SPAN session can include a VLAN as a source, which monitors all traffic in that VLAN except the control plane traffic.

Answer

A local SPAN session can have multiple destination ports to send the mirrored traffic to multiple analyzers.

Question 15

A network engineer runs the following command to verify DMVPN tunnel status:

R1# show ip nhrp detail

10.0.0.2/32 via Tunnel0
   Created: 00:10:15, Expire: 01:49:45
   Type: dynamic, Flags: unique registered
   NBMA: 192.168.1.2
   (no socket)

What does this output indicate?

Accepted Answer

The spoke 10.0.0.2 has registered with the hub and its NBMA address is 192.168.1.2.. The output shows a dynamic NHRP cache entry for a spoke (10.0.0.2) with NBMA address 192.168.1.2, indicating the spoke has registered and the entry is valid.

Answer

The spoke 10.0.0.2 is using a static NBMA mapping.

Answer

The NHRP entry is about to expire and needs re-registration.

Answer

The spoke has not registered; the entry is incomplete.