300-410 Practice Test 32 — 15 Questions

Question 1

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology 10.50.50.0/24
EIGRP-IPv4 Topology Entry for AS(100)/ID(192.168.1.1) for 10.50.50.0/24
  State: Active, Reply status: 0, Originating router: 192.168.1.1
  Routing Descriptor Blocks:
  10.1.1.2 (GigabitEthernet0/0), from 10.1.1.2, Send flag: 0x0
      Composite metric: (4294967295/4294967295), Route is Internal
      Vector metric:
        Minimum bandwidth: 100000 Kbit
        Total delay: 100 microseconds
        Reliability: 255/255
        Load: 1/255
        Minimum MTU: 1500
        Hop count: 1

Based on this output, what is the problem?

Accepted Answer

The route is in Active state with an infinite metric, indicating that the router has lost the route and is querying for a new path.. The route is in Active state with a composite metric of 4294967295 (the maximum 32-bit value, effectively infinite), which indicates that the router has lost the feasible successor and is actively sending queries to neighbors to find an alternative path. This is a classic sign of an EIGRP query process in progress, meaning the route is not stable or reachable.

Answer

The route is passive and stable.

Answer

The metric of 4294967295 is normal for a summary route.

Answer

The hop count of 1 indicates the route is one hop away and reachable.

Question 2

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

R1# debug ip routing vrf CUSTOMER_E

Output:
RT: add 10.3.3.0/24 via 10.1.1.2, ospf 200 metric [110/20]
RT: add 10.3.3.0/24 via 10.1.1.2, eigrp 100 metric [90/131072] tag 0
RT: closer admin distance for 10.3.3.0/24, adding via eigrp 100
RT: add 10.3.3.0/24 to routing table, via eigrp 100

What does this output indicate?

Accepted Answer

The route 10.3.3.0/24 is added from EIGRP 100 because it has a lower administrative distance than OSPF.. The debug output shows EIGRP 100 winning the route selection because the router compares administrative distance (AD) before metrics when routes come from different routing protocols. EIGRP's default AD of 90 is lower than OSPF's 110, so the EIGRP path is installed even though OSPF's metric of 20 looks numerically smaller. The line 'closer admin distance for 10.3.3.0/24, adding via eigrp 100' confirms this AD-based decision.

Answer

The route 10.3.3.0/24 is added from OSPF 200 because it has a lower metric.

Answer

The route 10.3.3.0/24 is added from both OSPF and EIGRP, creating an equal-cost path.

Answer

The route 10.3.3.0/24 is not added to the routing table due to a tag mismatch.

Question 3

A network engineer is troubleshooting a PBR (Policy-Based Routing) issue on router R5. The engineer configured a route-map to set the next-hop for traffic from a specific source subnet. The route-map is applied to the incoming interface, but traffic from the source subnet is still being forwarded using the regular routing table. The engineer verifies that the ACL matches the traffic correctly. What is the most likely cause?

Accepted Answer

The route-map is missing a 'set ip next-hop' command, or the next-hop is not reachable.. For PBR to actually change forwarding, the route-map must contain a 'set' clause (such as 'set ip next-hop' or 'set interface') that matches the ACL; if the set clause is missing or the specified next-hop is unreachable, the route-map matches but does nothing, and traffic falls back to the normal routing table. The scenario states the ACL matches correctly, so the failure is in the action, not the match.

Answer

The route-map is applied outbound instead of inbound on the interface.

Answer

The ACL is using a standard ACL, which cannot match source subnet correctly.

Answer

The route-map has a 'set default interface' command that overrides the next-hop.

Question 4

In MPLS, what is the default behavior of a Cisco IOS-XE router regarding the 'auto-summary' command for BGP routes?

Accepted Answer

Auto-summary is disabled by default for BGP.. In Cisco IOS and IOS-XE, BGP auto-summary is disabled by default. Unlike older Interior Gateway Protocols such as RIP or EIGRP (where auto-summary was historically enabled by default), BGP does not automatically summarize routes to their classful network boundaries unless explicitly configured with the 'auto-summary' command under the BGP router configuration. This default behavior ensures that BGP advertises the exact prefixes it learns, which is essential for precise routing in modern classless networks.

Answer

Auto-summary is enabled by default for BGP.

Answer

Auto-summary is enabled by default only for directly connected routes.

Answer

Auto-summary is disabled by default for BGP but enabled for OSPF.

Question 5

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

R1# show ip route vrf CUSTOMER_A summary

Output:
IP routing table name: CUSTOMER_A (0x00000001)
IP routing table maximum-paths: 32
Route Source    Networks    Subnets     Replicates  Overhead    Memory (bytes)
connected       2           0           0           0           576
static          1           0           0           0           288
eigrp 100       3           0           0           0           864
  Internal      3       0       0       0       864
  External      0       0       0       0       0
ospf 200        0           0           0           0           0
  Intra-area    0       0       0       0       0
  Inter-area    0       0       0       0       0
  External-1    0       0       0       0       0
  External-2    0       0       0       0       0
  NSSA-1        0       0       0       0       0
  NSSA-2        0       0       0       0       0
bgp 65000       0           0           0           0           0
  Internal      0       0       0       0       0
  External      0       0       0       0       0
Total           6           0           0           0           1728

What does this output indicate?

Accepted Answer

The VRF CUSTOMER_A has 6 routes, with EIGRP 100 providing 3 internal routes.. The summary shows 6 total routes in VRF CUSTOMER_A: 2 connected, 1 static, and 3 internal EIGRP 100 routes. OSPF 200 and BGP 65000 contribute zero routes. This matches option A exactly, confirming EIGRP is the only dynamic protocol populating the VRF.

Answer

The VRF CUSTOMER_A has 6 routes, all redistributed from BGP 65000.

Answer

The VRF CUSTOMER_A has 6 routes, with OSPF 200 providing 3 external routes.

Answer

The VRF CUSTOMER_A has 6 routes, all from connected and static only.

Question 6

A network engineer runs the following command on Router R2:

R2# show logging | include %SYS-5-CONFIG_I

*Mar  1 00:10:15.123: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 00:12:45.678: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 00:15:30.001: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 00:20:00.999: %SYS-5-CONFIG_I: Configured from console by console

Based on this output, what is the most likely problem?

Accepted Answer

The router is being reconfigured repeatedly from the console, which could indicate unauthorized access or a script issue.. The %SYS-5-CONFIG_I syslog message is generated whenever the running configuration is modified — in this case, 'Configured from console by console' indicates changes were made via the console line. Four such messages within ten minutes strongly suggest repeated reconfiguration, which could be unauthorized access, a misbehaving script, or a console session left open with automated commands. This is the most likely problem given the evidence.

Answer

The router has a memory leak causing frequent reloads.

Answer

The logging buffer is full and messages are being overwritten.

Answer

The syslog server is not reachable, so messages are only logged locally.

Question 7

A network engineer runs the following command on Router R1:

R1# show dmvpn
Legend: Attrb -> S: Static, D: Dynamic, I: Incomplete
        N: NATed, L: Local, X: No Socket
        #Ent -> Number of NHRP entries with same NBMA peer
        NHS Status: E => Expecting Replies, R => Responding, W => Waiting
        UpDn Time -> Up or Down Time for a Tunnel
==========================================================================
Interface: Tunnel0, IPv4 NHRP Details
Type:Hub, NHRP Peers:2,

# Ent  Peer NBMA Addr Peer Tunnel Addr State  UpDn Tm Attrb
 ----- --------------- ---------------- ----- -------- -----
     1 10.1.1.2        172.16.0.2        UP    00:02:15 D
     1 10.1.1.3        172.16.0.3        UP    00:01:45 D

Based on this output, which statement is correct?

Accepted Answer

Router R1 is a hub with two dynamically registered spokes.. The output shows that Router R1 is a hub (Type: Hub) with two NHRP peers that are dynamically registered (Attrb: D). The peers have tunnel addresses 172.16.0.2 and 172.16.0.3, and both are in UP state. Therefore, R1 is a hub with two dynamically registered spokes.

Answer

Router R1 is a spoke with two hub peers.

Answer

The NHRP peers are static and not dynamic.

Answer

One spoke is experiencing a registration failure.

Question 8

A network engineer runs the following command on Router R1:

R1# show snmp mib ifmib ifindex

ifIndex: 1
Interface: GigabitEthernet0/0
Description: GigabitEthernet0/0

ifIndex: 2
Interface: GigabitEthernet0/1
Description: GigabitEthernet0/1

ifIndex: 3
Interface: Loopback0
Description: Loopback0

ifIndex: 10
Interface: Tunnel0
Description: Tunnel0

Based on this output, which statement is correct?

Accepted Answer

The ifIndex for Loopback0 is 3.. The output of 'show snmp mib ifmib ifindex' displays the ifIndex values assigned to each interface by the SNMP agent. The table clearly shows Loopback0 with ifIndex 3, making option A correct. ifIndex values are not guaranteed to be sequential or start from 0; they are assigned dynamically and can have gaps, as seen with Tunnel0 having ifIndex 10.

Answer

The ifIndex values are assigned sequentially starting from 0.

Answer

GigabitEthernet0/0 has ifIndex 2.

Answer

Tunnel0 has ifIndex 3.

Question 9

Examine this configuration:
```
router ospf 1
 distance ospf intra-area 150 inter-area 160 external 170
```
What is the effect of this command?

Accepted Answer

It sets the administrative distance for intra-area OSPF routes to 150, inter-area to 160, and external to 170.. This command sets different administrative distances for different OSPF route types: intra-area to 150, inter-area to 160, external to 170.

Answer

It sets the administrative distance for all OSPF routes to 150.

Answer

It sets the administrative distance for OSPF routes to 150, but only for routes learned from area 1.

Answer

It sets the administrative distance for OSPF external routes to 170 and leaves intra-area and inter-area at default.

Question 10

Examine this configuration:

interface GigabitEthernet0/4
 ipv6 address 2001:db8:2::1/64
 ipv6 verify unicast source reachable-via any

What is the effect of the 'ipv6 verify unicast source reachable-via any' command?

Accepted Answer

The router performs loose uRPF: the source address must be reachable via any route in the FIB.. The command 'ipv6 verify unicast source reachable-via any' enables loose unicast Reverse Path Forwarding (uRPF) for IPv6. In loose mode, the router checks that the source address of an incoming packet is reachable via any route in the Forwarding Information Base (FIB), not necessarily through the receiving interface. This is the correct behavior described in option B.

Answer

The router performs strict uRPF: the source address must be reachable via the same interface the packet arrived on.

Answer

The router drops all packets with source addresses not in the same subnet as the interface.

Answer

The command is invalid because 'ipv6 verify unicast' requires a route-map.

Question 11

An engineer configures unicast Reverse Path Forwarding (uRPF) in strict mode on an interface connected to a network with asymmetric routing. Users report intermittent connectivity issues. Which is the most likely explanation?

Accepted Answer

Asymmetric routing causes packets to arrive on an interface that is not the best return path, so uRPF drops them.. Unicast Reverse Path Forwarding (uRPF) in strict mode checks that the source IP address of an incoming packet has a route in the routing table pointing back out the same interface on which the packet arrived. In an asymmetric routing scenario, packets may arrive on an interface that is not the best return path, causing the uRPF check to fail and the packet to be dropped. This explains the intermittent connectivity issues reported by users.

Answer

The uRPF configuration is missing the 'allow-default' option.

Answer

The routing table does not have a route for the source IP.

Answer

The interface has multiple IP addresses.

Question 12

Review the following configuration:

ipv6 access-list FILTER
 permit tcp 2001:db8:1::/48 any eq 80
 permit tcp 2001:db8:1::/48 any eq 443
 deny ipv6 any any

interface GigabitEthernet0/3
 ipv6 traffic-filter FILTER out

What is the effect of this configuration?

Accepted Answer

Only HTTP and HTTPS traffic from 2001:db8:1::/48 is permitted outbound; all other traffic is denied.. The IPv6 ACL named FILTER explicitly permits TCP traffic from source prefix 2001:db8:1::/48 to any destination on ports 80 (HTTP) and 443 (HTTPS), and then denies all other IPv6 traffic. Applied as an outbound traffic filter on GigabitEthernet0/3, this configuration restricts outbound traffic to only HTTP and HTTPS sessions originating from the specified prefix.

Answer

All traffic from 2001:db8:1::/48 is permitted because the ACL does not specify destination prefix.

Answer

The ACL is misconfigured because 'out' should be 'in' for source-based filtering.

Answer

The ACL permits all traffic because the deny statement is implicit.

Question 13

Which TWO configuration steps are required to apply an IPv4 extended access list to an interface in Cisco IOS? (Choose TWO.)

Accepted Answer

Configure the ACL using access-list or ip access-list commands.. An IPv4 extended ACL must first be defined using either the numbered `access-list` command or the named `ip access-list extended` command before it can be applied. Option B is correct because the `ip access-group` command is the only way to bind a configured ACL to an interface in Cisco IOS, specifying the direction (in or out) and optionally the VLAN filter.

Answer

Create the ACL directly under the interface configuration mode.

Answer

Use the access-class command on the interface.

Answer

Enable the ACL with the ip inspect command.

Question 14

A service provider network is experiencing MPLS label distribution failures between R1 and R2. R1 has: event manager applet LDP-MONITOR event syslog pattern "%LDP-4-ERROR" action 1.0 cli command "enable" action 2.0 cli command "clear mpls ldp neighbor *" action 3.0 syslog msg "Cleared LDP neighbors". Router R2 shows: LDP session is down, and logs show repeated LDP errors. What is the root cause?

Accepted Answer

The EEM applet clears all LDP neighbors upon any LDP error, preventing the session from stabilizing.. The EEM applet is configured to trigger on the syslog pattern '%LDP-4-ERROR' and immediately execute 'clear mpls ldp neighbor *', which tears down all LDP sessions on R1. Each time LDP tries to re-establish and logs another error, the applet fires again, creating a loop that prevents the LDP session from ever stabilizing. The root cause is the overly aggressive automated remediation, not an LDP configuration issue on R2.

Answer

The LDP router-id is misconfigured on R1.

Answer

The syslog pattern matches only severity 4, but LDP errors are severity 3.

Answer

The MPLS label range is exhausted on R1.

Question 15

In MPLS L3VPN, what is the default behavior of BGP auto-summary on Cisco IOS-XE?

Accepted Answer

Auto-summary is disabled by default.. BGP auto-summary is disabled by default on Cisco IOS-XE. When enabled, it would summarize subnets to their classful boundary, but this is not default.

Answer

Auto-summary is enabled by default for all BGP sessions.

Answer

Auto-summary is enabled only for iBGP sessions.

Answer

Auto-summary is disabled for eBGP but enabled for iBGP.