300-410 Practice Test 29 — 15 Questions

Question 1

An engineer configures NAT overload (PAT) on a router to translate internal addresses to a single public IP. Users can browse the web, but some applications that use non-standard ports fail. Which is the most likely explanation?

Accepted Answer

The application uses protocols that do not have port numbers, such as GRE, and PAT cannot handle them.. PAT uses port numbers to differentiate translations. Some applications use protocols that do not have port numbers (e.g., GRE, IPsec ESP) or use ports that conflict with NAT's own port allocation. Additionally, if the application uses embedded IP addresses or ports (e.g., FTP, SIP), PAT may not translate them correctly without ALG support.

Answer

The NAT pool is exhausted.

Answer

The inside interface is not configured correctly.

Answer

The outside interface has a different MTU.

Question 2

Which THREE statements about NAT and PAT behavior in Cisco IOS are true? (Choose THREE.)

Accepted Answer

PAT allows multiple inside hosts to share a single public IP address by using unique source port numbers.. PAT (overload) uses unique port numbers to distinguish multiple inside hosts sharing a single public IP. The NAT table stores five tuples (protocol, inside local IP:port, inside global IP:port, outside local IP:port, outside global IP:port). 'ip nat inside source list 1 interface GigabitEthernet0/0 overload' is the correct syntax for PAT with an interface. The 'ip nat inside source static' command creates a one-to-one mapping and does not use overload. The 'ip nat pool' command defines a range of addresses, but PAT can also use a single interface IP.

Answer

The 'ip nat inside source static' command automatically enables PAT when multiple inside hosts are configured.

Answer

The 'ip nat pool' command is required for all PAT configurations.

Question 3

A network engineer runs the following command to troubleshoot Control Plane Policing (CoPP):

R1# show policy-map control-plane input class class-default
  Class-map: class-default (match-any)
    140091 packets, 12345678 bytes
    5 minute offered rate 1000 bps, drop rate 0 bps
    Match: any
    police:
        cir 8000 bps, bc 1500 bytes
        conformed 140091 packets, 12345678 bytes; actions:
          transmit
        exceeded 0 packets, 0 bytes; actions:
          drop
        violated 0 packets, 0 bytes; actions:
          drop

What does this output indicate?

Accepted Answer

CoPP is rate-limiting traffic to 8000 bps and not dropping any packets.. The output shows that the CoPP policy on the control-plane input class-default is policing traffic to 8000 bps. All packets are conforming and being transmitted, with no drops.

Answer

CoPP is dropping all traffic to the control plane.

Answer

CoPP is not configured; the class-default shows no action.

Answer

CoPP is dropping packets due to exceeding the rate.

Question 4

An engineer configures OSPF on two routers connected via a serial link. Both routers have 'ip ospf network point-to-point' configured, but the link is actually a Frame Relay multipoint subinterface. The OSPF neighbors remain stuck in EXSTART state. Which is the most likely explanation?

Accepted Answer

The MTU on the serial link is not consistent between the two routers, causing DBD packets to be dropped.. OSPF network type mismatch between the configured point-to-point and the actual multipoint topology can cause MTU mismatch issues. On a multipoint subinterface, the default MTU may be lower, and OSPF uses the interface MTU to determine the maximum packet size. If the MTU is not consistent, the Database Description (DBD) packets may be dropped, causing the neighbor to remain in EXSTART.

Answer

The OSPF hello timer is set too high, causing the neighbor to time out.

Answer

The area ID is different on the two routers.

Answer

The OSPF router ID is duplicated.

Question 5

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

R1# show ip route vrf CUSTOMER summary
IP routing table name is CUSTOMER (0x1)
IP routing table maximum-paths is 32
Route Source    Networks    Subnets    Overhead    Memory (bytes)
connected       2           0          0           320
static          1           0          0           160
eigrp 100       3           0          0           480
  Internal      3
Total           6           0          0           960

What does this output indicate?

Accepted Answer

The VRF CUSTOMER routing table has 6 routes, including static and EIGRP routes.. The output shows the routing table summary for VRF CUSTOMER, with 6 total routes: 2 connected, 1 static, and 3 EIGRP routes. No red flags are present.

Answer

The VRF CUSTOMER routing table is empty.

Answer

The VRF CUSTOMER has only connected routes.

Answer

The VRF CUSTOMER routing table has an error due to overlapping subnets.

Question 6

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

Accepted Answer

110. The default administrative distance for OSPF is 110. This is a Cisco IOS default value used when comparing routes from different routing protocols.

Answer

90

Answer

100

Answer

120

Question 7

An engineer configures EIGRP named mode on a router and uses an offset-list to increase the feasible distance (FD) of a specific route. Unexpectedly, the route is still installed in the routing table with the original metric. Which is the most likely explanation?

Accepted Answer

The offset-list was applied to outbound updates instead of inbound, so it affected the FD on the neighbor, not the local router.. In EIGRP, the offset-list modifies the metric of routes received or sent, but it affects the FD only if the route is the successor. However, if the route is a feasible successor, the offset-list may not change the FD for the successor path. Additionally, the offset-list in named mode applies to the topology table entry, but the route selection still uses the original metric if the offset-list is applied incorrectly (e.g., to the wrong direction).

Answer

The offset-list value was too large, causing the route to be suppressed.

Answer

The offset-list was applied to the wrong interface.

Answer

The route is a connected route, and offset-lists do not affect connected routes.

Question 8

What is the default OSPF dead interval on a point-to-point network when the hello interval is set to 10 seconds?

Accepted Answer

40 seconds. By default, the OSPF dead interval is four times the hello interval. On point-to-point networks, the default hello interval is 10 seconds, so the dead interval is 40 seconds.

Answer

10 seconds

Answer

20 seconds

Answer

30 seconds

Question 9

Which loop prevention mechanism does RIP use to avoid routing loops?

Accepted Answer

Maximum hop count of 15. RIP uses multiple loop prevention mechanisms, including maximum hop count (15), split horizon, route poisoning, and hold-down timers. The maximum hop count of 15 (with 16 considered infinite) is a fundamental loop prevention method.

Answer

TTL expiration in IP header

Answer

DUAL algorithm

Answer

LSA aging

Question 10

What is the default OSPF network type for a serial interface configured with HDLC encapsulation on Cisco routers?

Accepted Answer

Point-to-point. By default, Cisco IOS sets serial interfaces with HDLC or PPP encapsulation to OSPF network type point-to-point. This is because these encapsulations typically indicate a direct link between two routers.

Answer

Broadcast

Answer

Non-broadcast (NBMA)

Answer

Point-to-multipoint

Question 11

An engineer configures mutual redistribution between OSPF and EIGRP on a router. After a few minutes, the router's CPU spikes and routes start flapping. Which is the most likely explanation?

Accepted Answer

The redistribution is creating a routing loop because there is no route tagging or filtering to prevent re-redistribution.. Mutual redistribution without route tagging can cause a routing loop where a route redistributed from OSPF into EIGRP is then redistributed back into OSPF with a different metric, causing the router to prefer the redistributed route and create a loop. This leads to route flapping and CPU spikes as the router continuously updates.

Answer

The seed metric is not configured, so the routes are not redistributed.

Answer

The administrative distance is set too low, causing the router to prefer the wrong route.

Answer

The OSPF process ID is the same on both routers.

Question 12

Which EIGRP packet type is used to confirm receipt of an update during reliable transport?

Accepted Answer

ACK. EIGRP uses Reliable Transport Protocol (RTP). When a router receives an update, it sends an ACK packet (a hello packet with no data) to confirm receipt. ACKs are always sent unreliably (unicast).

Answer

Hello

Answer

Update

Answer

Query

Question 13

Which TWO statements about SNMPv3 configuration on Cisco IOS XE are true? (Choose TWO.)

Accepted Answer

The 'snmp-server user' command can specify an authentication and privacy password for a user.. SNMPv3 supports both noAuthNoPriv and authPriv security levels. The engine ID is automatically generated based on the router's MAC address but can be manually configured. The 'snmp-server group' command does not directly specify the username; it creates a group that users belong to. The 'snmp-server user' command requires the engine ID to be specified if the remote engine ID is known, but for local users it uses the local engine ID. The 'snmp-server host' command can specify a username for SNMPv3 informs, but the default for traps is to use the community string for SNMPv1/v2c.

Answer

The 'snmp-server group' command creates a group and assigns a username to it.

Answer

The engine ID is automatically generated and cannot be manually configured.

Answer

SNMPv3 supports only the authPriv security level.

Question 14

An engineer configures a DMVPN Phase 2 network. Spoke routers can communicate with the hub, but spoke-to-spoke traffic does not trigger a direct tunnel. Which is the most likely explanation?

Accepted Answer

The hub router is missing the 'ip nhrp redirect' command.. In DMVPN Phase 2, spoke-to-spoke tunnels require NHRP redirect messages from the hub and NHRP shortcut requests from the spoke. If the hub does not have 'ip nhrp redirect' configured, it will not send redirect messages, and spokes will not attempt to build a direct tunnel.

Answer

The spoke routers have 'ip nhrp shortcut' configured.

Answer

The tunnel mode is set to gre multipoint on the spokes.

Answer

The NHRP authentication is mismatched.

Question 15

Which TWO actions will prevent a Cisco IOS router from responding to ICMP echo requests on an interface? (Choose TWO.)

Accepted Answer

Apply an inbound access-list on the interface that denies ICMP echo requests.. The 'no ip unreachables' command disables ICMP unreachable messages but does not affect echo replies. The 'no ip redirects' disables ICMP redirects. The 'no ip proxy-arp' disables proxy ARP. The 'access-group' with a deny rule for ICMP echo can block the replies. The 'ip icmp echo-reply disable' global command disables all ICMP echo replies. The 'ip access-group' applied outbound on the interface would affect traffic leaving, not incoming echo requests.

Answer

Configure 'no ip unreachables' on the interface.

Answer

Configure 'no ip redirects' on the interface.

Answer

Configure 'no ip proxy-arp' on the interface.