Quiz On CCENT/CCNA ICND2 CHAPT. 4 & 5

1. What does the acronym VLSM stand for?

Variable-length subnet mask

Very long subnet mask

Vociferous longitudinal subnet mask

Vector-length subnet mask

Vector loop subnet mask

Note that sometimes VLSM stands for variable-length subnet masking, which refers to the process of using different masks in the same classful network, whereas variablelength subnet mask refers to the subnet masks themselves.

Explanation

Note that sometimes VLSM stands for variable-length subnet masking, which refers to the process of using different masks in the same classful network, whereas variablelength subnet mask refers to the subnet masks themselves.

2. Which of the following commands correctly conﬁgures a static route?

Ip route 10.1.3.0 255.255.255.0 10.1.130.253

Ip route 10.1.3.0 serial 0

Ip route 10.1.3.0 /24 10.1.130.253

Ip route 10.1.3.0 /24 serial 0

The correct syntax lists a subnet number, then a subnet mask in dotted decimal form, and then either an outgoing interface or a next-hop IP address.

Explanation

The correct syntax lists a subnet number, then a subnet mask in dotted decimal form, and then either an outgoing interface or a next-hop IP address.

3. A PC user turns on her computer, and as soon as the computer is up and working, she opens a command prompt. From there, she issues the ping 2.2.2.2 command, and the ping shows 100 percent success. The PC’s IP address is 1.1.1.1 with mask 255.255.255.0. Which of the following settings would be required on the PC to support the successful ping?

The IP address of a DNS server

The IP address of a default gateway

The IP address of an ARP server

The IP address of a DHCP server

The ping 2.1.1.2 command does not use a host name, so no DNS server is required. A DHCP client does not need to know the DHCP server’s IP address to use DHCP. There’s no such thing as an ARP server. However, to send the packet to another subnet,the PC needs to know the IP address of its default gateway.

Explanation

The ping 2.1.1.2 command does not use a host name, so no DNS server is required. A DHCP client does not need to know the DHCP server’s IP address to use DHCP. There’s no such thing as an ARP server. However, to send the packet to another subnet,the PC needs to know the IP address of its default gateway.

4. A PC user turns on her computer, and as soon as the computer is up and working, she
opens a web browser to browse https://www.ciscopress.com. Which protocol(s) would
deﬁnitely not be used by the PC during this process?

DHCP

DNS

ARP

ICMP

The host might need to use Dynamic Host Configuration Protocol (DHCP) to acquire an IP address, and it would likely use Domain Name System (DNS) to resolve www.ciscopress.com into an IP address. It would also use Address Resolution Protocol (ARP) to find the default gateway’s MAC address, because the ARP cache would have
been cleared as part of the boot process.

Explanation

The host might need to use Dynamic Host Configuration Protocol (DHCP) to acquire an IP address, and it would likely use Domain Name System (DNS) to resolve www.ciscopress.com into an IP address. It would also use Address Resolution Protocol (ARP) to find the default gateway’s MAC address, because the ARP cache would have
been cleared as part of the boot process.

5. A router has been conﬁgured with the ip classless global conﬁguration command. The router receives a packet destined to IP address 168.13.4.1. The following text lists the contents of the router’s routing table. Which of the following is true about how this router forwards the packet?

It is forwarded to 168.13.100.3.

It is forwarded to 168.13.1.101.

It is forwarded out interface Fa0/0, directly to the destination host.

The router discards the packet.

With classless routing enabled, the router uses the default route if no other routes are matched. The line beginning “Gateway of last resort . . .” lists the IP address of the next-hop router, 168.13.1.101, which will be used as the default route.

Explanation

With classless routing enabled, the router uses the default route if no other routes are matched. The line beginning “Gateway of last resort . . .” lists the IP address of the next-hop router, 168.13.1.101, which will be used as the default route.

6. Which of the following routing protocols support VLSM?

RIP-1

RIP-2

EIGRP

OSPF

RIP-2, EIGRP, and OSPF are the routing protocols that support VLSM. VLSM (Variable Length Subnet Masking) allows the use of different subnet mask lengths within the same network, which helps in efficient utilization of IP addresses. RIP-1 does not support VLSM as it only uses classful routing, where the subnet mask is fixed for all subnets. However, RIP-2, EIGRP, and OSPF support VLSM by allowing the use of different subnet masks for different subnets within the network.

Explanation

RIP-2, EIGRP, and OSPF are the routing protocols that support VLSM. VLSM (Variable Length Subnet Masking) allows the use of different subnet mask lengths within the same network, which helps in efficient utilization of IP addresses. RIP-1 does not support VLSM as it only uses classful routing, where the subnet mask is fixed for all subnets. However, RIP-2, EIGRP, and OSPF support VLSM by allowing the use of different subnet masks for different subnets within the network.

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7. Which of the following summarized subnets is the smallest (smallest range of addresses) summary route that includes subnets 10.3.95.0, 10.3.96.0, and 10.3.97.0, mask 255.255.255.0?

10.0.0.0 255.0.0.0

10.3.0.0 255.255.0.0

10.3.64.0 255.255.192.0

10.3.64.0 255.255.224.0

All the listed answers include the range of all three subnets, except for 10.3.64.0 255.255.224.0, which implies an address range of 10.3.64.0–10.3.95.255. Of the other three answers, 10.3.64.0 255.255.192.0 is the smallest range (10.3.64.0–10.3.127.255). It also happens to be the smallest single summary route that includes all three subnets listed in the question.

Explanation

All the listed answers include the range of all three subnets, except for 10.3.64.0 255.255.224.0, which implies an address range of 10.3.64.0–10.3.95.255. Of the other three answers, 10.3.64.0 255.255.192.0 is the smallest range (10.3.64.0–10.3.127.255). It also happens to be the smallest single summary route that includes all three subnets listed in the question.

8. Which of the following must be true before IOS lists a route as “S” in the output of a show ip route command?

The IP address must be conﬁgured on an interface.

The router must receive a routing update from a neighboring router.

The ip route command must be added to the conﬁguration.

The ip address command must use the special keyword.

The interface must be up and up.

The “S” code means that the route is a static route, which is defined with the ip route global configuration command.

Explanation

The “S” code means that the route is a static route, which is defined with the ip route global configuration command.

9. R1 has conﬁgured interface Fa0/0 with the ip address 10.5.48.1 255.255.240.0 command. Which of the following subnets, when conﬁgured on another interface on R1, would not be considered to be an overlapping VLSM subnet?

10.5.0.0 255.255.240.0

10.4.0.0 255.254.0.0

10.5.32.0 255.255.224.0

10.5.0.0 255.255.128.0

Subnet 10.5.0.0 255.255.240.0 implies range 10.5.0.0–10.5.15.255, which does not overlap. 10.4.0.0 255.254.0.0 implies range 10.4.0.0–10.5.255.255, which does overlap. 10.5.32.0 255.255.224.0 implies range 10.5.32.0–10.5.63.255, which does overlap. 10.5.0.0 255.255.128.0 implies range 10.5.0.0– 10.5.127.255, which does overlap.

Explanation

Subnet 10.5.0.0 255.255.240.0 implies range 10.5.0.0–10.5.15.255, which does not overlap. 10.4.0.0 255.254.0.0 implies range 10.4.0.0–10.5.255.255, which does overlap. 10.5.32.0 255.255.224.0 implies range 10.5.32.0–10.5.63.255, which does overlap. 10.5.0.0 255.255.128.0 implies range 10.5.0.0– 10.5.127.255, which does overlap.

10. Which of the following is affected by whether a router is performing classful or classless routing?

When to use a default route

When to use masks in routing updates

When to convert a packet’s destination IP address to a network number

When to perform queuing based on the classiﬁcation of a packet into a particular queue

The correct answer is "When to use a default route." This is because the decision to use a default route or not is influenced by whether a router is performing classful or classless routing. In classful routing, a default route is used when there is no specific route for a destination network. In classless routing, a default route is used as a backup or last resort when there are no more specific routes available for a destination network. Therefore, the choice of using a default route is affected by the routing protocol and its classification as classful or classless.

Explanation

The correct answer is "When to use a default route." This is because the decision to use a default route or not is influenced by whether a router is performing classful or classless routing. In classful routing, a default route is used when there is no specific route for a destination network. In classless routing, a default route is used as a backup or last resort when there are no more specific routes available for a destination network. Therefore, the choice of using a default route is affected by the routing protocol and its classification as classful or classless.

11. An internetwork has a discontiguous network 10.0.0.0, and it is having problems. All routers use RIP-1 with all default conﬁgurations. Which of the following answers lists an action that, by itself, would solve the problem and allow the discontiguous network?

Migrate all routers to use OSPF, using as many defaults as is possible.

Disable autosummarization with the no auto-summary RIP conﬁguration command.

Migrate to EIGRP, using as many defaults as is possible.

The problem cannot be solved without ﬁrst making network 10.0.0.0 contiguous.

Discontiguous networks are allowed as long as autosummarization is disabled. OSPF does not even support autosummarization, so using OSPF would solve the problem. RIP-1 cannot disable autosummarization. EIGRP can disable autosummarization, but it is on by default.

Explanation

Discontiguous networks are allowed as long as autosummarization is disabled. OSPF does not even support autosummarization, so using OSPF would solve the problem. RIP-1 cannot disable autosummarization. EIGRP can disable autosummarization, but it is on by default.

12. Which of the following routing protocols support manual route summarization?

RIP-1

RIP-2

EIGRP

OSPF

RIP-2, EIGRP, and OSPF support manual route summarization. Manual route summarization is a technique used to reduce the size of routing tables by aggregating multiple network prefixes into a single summary route. RIP-2, EIGRP, and OSPF allow network administrators to manually configure summary routes, which improves network efficiency and reduces the amount of routing information exchanged between routers.

Explanation

RIP-2, EIGRP, and OSPF support manual route summarization. Manual route summarization is a technique used to reduce the size of routing tables by aggregating multiple network prefixes into a single summary route. RIP-2, EIGRP, and OSPF allow network administrators to manually configure summary routes, which improves network efficiency and reduces the amount of routing information exchanged between routers.

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13. Which routing protocol(s) perform(s) autosummarization by default?

RIP-1

RIP-2

EIGRP

OSPF

RIP-1, RIP-2, and EIGRP perform autosummarization by default. Autosummarization is a feature in routing protocols that allows the summarization of multiple subnets into a single summarized route. This helps in reducing the size of the routing table and conserving network resources. OSPF, on the other hand, does not perform autosummarization by default.

Explanation

RIP-1, RIP-2, and EIGRP perform autosummarization by default. Autosummarization is a feature in routing protocols that allows the summarization of multiple subnets into a single summarized route. This helps in reducing the size of the routing table and conserving network resources. OSPF, on the other hand, does not perform autosummarization by default.

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14. Which of the following summarized subnets is not a valid summary that includes subnets 10.1.55.0, 10.1.56.0, and 10.1.57.0, mask 255.255.255.0?

10.0.0.0 255.0.0.0

10.1.0.0 255.255.0.0

10.1.55.0 255.255.255.0

10.1.48.0 255.255.248.0

10.1.32.0 255.255.224.0

10.0.0.0 255.0.0.0 implies a range of all addresses that begin with 10, and 10.1.0.0 255.255.0.0 implies a range of all addresses that begin with 10.1, so both these answers include all the address ranges listed in the question. 10.1.32.0 255.255.224.0 implies a range of 10.1.32.0–10.1.63.255, which includes all addresses listed in the question. 10.1.55.0 255.255.255.0 implies a range of only 10.1.55.0–10.1.55.255, which does not include all addresses. 10.1.48.0 255.255.248.0 implies a range of 10.1.48.0–10.1.55.255, which omits two of the subnets listed in the question.

Explanation

10.0.0.0 255.0.0.0 implies a range of all addresses that begin with 10, and 10.1.0.0 255.255.0.0 implies a range of all addresses that begin with 10.1, so both these answers include all the address ranges listed in the question. 10.1.32.0 255.255.224.0 implies a range of 10.1.32.0–10.1.63.255, which includes all addresses listed in the question. 10.1.55.0 255.255.255.0 implies a range of only 10.1.55.0–10.1.55.255, which does not include all addresses. 10.1.48.0 255.255.248.0 implies a range of 10.1.48.0–10.1.55.255, which omits two of the subnets listed in the question.

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Quiz On CCENT/CCNA Icnd2 Chapt. 4 & 5