Exam Code: 100-105 (Practice Exam Latest Test Questions VCE PDF)
Exam Name: Cisco Interconnecting Cisco Networking Devices Part 1 (ICND1 v3.0)
Certification Provider: Cisco
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2021 Mar 100-105 exam

Q61. - (Topic 7) 

Which component of a routing table entry represents the subnet mask? 

A. routing protocol code 

B. prefix 

C. metric 

D. network mask 

Answer:

Explanation: 

IP Routing Table Entry TypesAn entry in the IP routing table contains the following information in the order presented: Network ID. The network ID or destination corresponding to the route. The network ID can be class-based, subnet, or supernet network ID, or an IP address for a host route. Network Mask. The mask that is used to match a destination IP address to the network ID. Next Hop. The IP address of the next hop. Interface. An indication of which network interface is used to forward the IP packet. Metric. A number used to indicate the cost of the route so the best route among possible multiple routes to the same destination can be selected. A common use of the metric is to indicate the number of hops (routers crossed) to the network ID. Routing table entries can be used to store the following types of routes: Directly Attached Network IDs. Routes for network IDs that are directly attached. For directly attached networks, the Next Hop field can be blank or contain the IP address of the interface on that network. Remote Network IDs. Routes for network IDs that are not directly attached but are available across other routers. For remote networks, the Next Hop field is the IP address of a local router in between the forwarding node and the remote network. Host Routes. A route to a specific IP address. Host routes allow routing to occur on a per-IP address basis. For host routes, the network ID is the IP address of the specified host and the network mask is 255.255.255.255. Default Route. The default route is designed to be used when a more specific network ID or host route is not found. The default route network ID is 0.0.0.0 with the network mask of 

0.0.0.0. 


Q62. - (Topic 1) 

How does a switch differ from a hub? 

A. A switch does not induce any latency into the frame transfer time. 

B. A switch tracks MAC addresses of directly-connected devices. 

C. A switch operates at a lower, more efficient layer of the OSI model. 

D. A switch decreases the number of broadcast domains. 

E. A switch decreases the number of collision domains. 

Answer:

Explanation: 

Some of the features and functions of a switch include: 

A switch is essentially a fast, multi-port bridge, which can contain dozens of ports. 

Rather than creating two collision domains, each port creates its own collision domain. 

In a network of twenty nodes, twenty collision domains exist if each node is plugged into its 

own switch port. 

If an uplink port is included, one switch creates twenty-one single-node collision domains. 

A switch dynamically builds and maintains a Content-Addressable Memory (CAM) table, 

holding all of the necessary MAC information for each port. 

For a detailed description of how switches operate, and their key differences to hubs, see 

the reference link below. 

Reference: http://www.cisco.com/warp/public/473/lan-switch-cisco.shtml 


Q63. - (Topic 3) 

Which statement about IPv6 is true? 

A. Addresses are not hierarchical and are assigned at random. 

B. Only one IPv6 address can exist on a given interface. 

C. There are 2.7 billion addresses available. 

D. Broadcasts have been eliminated and replaced with multicasts. 

Answer:

Explanation: 

IPv6 has three types of addresses, which can be categorized by type and scope: 

Unicast addresses. A packet is delivered to one interface. 

Multicast addresses. A packet is delivered to multiple interfaces. 

Anycast addresses. A packet is delivered to the nearest of multiple interfaces (in terms of 

routing distance). 

IPv6 does not use broadcast messages. 

Unicast and anycast addresses in IPv6 have the following scopes (for multicast addresses, 

the scope are built into the address structure): 

Link-local. The scope is the local link (nodes on the same subnet). 

Site-local. The scope is the organization (private site addressing). 

Global. The scope is global (IPv6 Internet addresses). 

In addition, IPv6 has special addresses such as the loopback address. The scope of a 

special address depends on the type of special address. 

Much of the IPv6 address space is unassigned. 

http://technet.microsoft.com/en-us/library/cc757359(v=ws.10).aspx 


Q64. - (Topic 5) 

What are two recommended ways of protecting network device configuration files from outside network security threats? (Choose two.) 

A. Allow unrestricted access to the console or VTY ports. 

B. Use a firewall to restrict access from the outside to the network devices. 

C. Always use Telnet to access the device command line because its data is automatically encrypted. 

D. Use SSH or another encrypted and authenticated transport to access device configurations. 

E. Prevent the loss of passwords by disabling password encryption. 

Answer: B,D 

Explanation: 

Using a firewall is a must for networks of any size to protect the internal network from outside threats and unauthorized access. SSH traffic is encrypted while telnet is not, so it is always recommended to use SSH. 


Q65. - (Topic 3) 

Refer to the output of the corporate router routing table shown in the graphic. 

The corporate router receives an IP packet with a source IP address of 192.168.214.20 and a destination address of 192.168.22.3. 

What will the router do with this packet? 

A. It will encapsulate the packet as Frame Relay and forward it out interface Serial 0/0.117. 

B. It will discard the packet and send an ICMP Destination Unreachable message out interface FastEthernet 0/0. 

C. It will forward the packet out interface Serial 0/1 and send an ICMP Echo Reply message out interface serial 0/0.102. 

D. It will change the IP packet to an ARP frame and forward it out FastEthernet 0/0. 

Answer:

Explanation: 

Since the destination network is not in the routing table, and no default gateway has been configured, the router will discard the packet and send an ICMP Destination Unreachable message out interface FastEthernet 0/0. It knows to send it out Fa 0/0 because the routing table for the source IP address of 192.168.214.20 shows it was learned from the Fa 0/0 interface. 


Most recent 100-105 exam topics:

Q66. - (Topic 1) 

How does TCP differ from UDP? (Choose two.) 

A. TCP provides best effort delivery. 

B. TCP provides synchronized communication. 

C. TCP segments are essentially datagrams. 

D. TCP provides sequence numbering of packets. 

E. TCP uses broadcast delivery. 

Answer: B,D 

Explanation: 

Because TCP is a connection-oriented protocol responsible for ensuring the transfer of a datagram from the source to destination machine (end-to-end communications), TCP must receive communications messages from the destination machine to acknowledge receipt of the datagram. The term virtual circuit is usually used to refer to the handshaking that goes on between the two end machines, most of which are simple acknowledgment messages (either confirmation of receipt or a failure code) and datagram sequence numbers. Rather than impose a state within the network to support the connection, TCP uses synchronized state between the two endpoints. This synchronized state is set up as part of an initial connection process, so TCP can be regarded as a connection-oriented protocol. Much of the protocol design is intended to ensure that each local state transition is communicated to, and acknowledged by, the remote party. 

Reference: http://en.wikibooks.org/wiki/Communication_Networks/TCP_and_UDP_Protocols 


Q67. - (Topic 3) 

Which two statements describe the process identifier that is used in the command to configure OSPF on a router? (Choose two.) 

Router(config)# router ospf 1 

A. All OSPF routers in an area must have the same process ID. 

B. Only one process number can be used on the same router. 

C. Different process identifiers can be used to run multiple OSPF processes 

D. The process number can be any number from 1 to 65,535. 

E. Hello packets are sent to each neighbor to determine the processor identifier. 

Answer: C,D 

Explanation: 

Multiple OSPF processes can be configured on a router using multiple process ID’s. 

The valid process ID’s are shown below: Edge-B(config)#router ospf <1-65535> Process ID 


Q68. - (Topic 5) 

From which of the following attacks can Message Authentication Code (MAC) shield your network? 

A. DoS 

B. DDoS 

C. spoofing 

D. SYN floods 

Answer:

Explanation: 

Message Authentication Code (MAC) can shield your network from spoofing attacks. Spoofing, also known as masquerading, is a popular trick in which an attacker intercepts a network packet, replaces the source address of the packets header with the address of the authorized host, and reinserts fake information which is sent to the receiver. This type of attack involves modifying packet contents. MAC can prevent this type of attack and ensure data integrity by ensuring that no data has changed. MAC also protects against frequency analysis, sequence manipulation, and ciphertext-only attacks. MAC is a secure message digest that requires a secret key shared by the sender and receiver, making it impossible for sniffers to change both the data and the MAC as the receiver can detect the changes. A denial-of-service (DoS) attack floods the target system with unwanted requests, causing the loss of service to users. One form of this attack generates a flood of packets requesting a TCP connection with the target, tying up all resources and making the target unable to service other requests. MAC does not prevent DoS attacks. Stateful packet filtering is the most common defense against a DoS attack. A Distributed Denial of Service attack (DDoS) occurs when multiple systems are used to flood the network and tax the resources of the target system. Various intrusion detection systems, utilizing stateful packet filtering, can protect against DDoS attacks. In a SYN flood attack, the attacker floods the target with spoofed IP packets and causes it to either freeze or crash. A SYN flood attack is a type of denial of service attack that exploits the buffers of a device that accept incoming connections and therefore cannot be prevented by MAC. Common defenses against a SYN flood attack include filtering, reducing the SYN-RECEIVED timer, and implementing SYN cache or SYN cookies. 


Q69. - (Topic 3) 

Which command can you use to manually assign a static IPV6 address to a router interface? 

A. ipv6 address PREFIX_1::1/64 

B. ipv6 autoconfig 2001:db8:2222:7272::72/64 

C. ipv6 autoconfig 

D. ipv6 address 2001:db8:2222:7272::72/64 

Answer:

Explanation: 

An example of configuring IPv6 on an interface is shown below: Router(config)# interface fastethernet 0/1 Router(config-if)# ipv6 address 3000::2222:1/64 


Q70. - (Topic 5) 

What is the purpose of the switchport command? 

Switch(config-if)# switchport port-security maximum 1 

Switch(config-if)# switchport port-security mac-address 0018.DE8B.4BF8 

A. It ensures that only the device with the MAC address 0018.DE8B.4BF8 will be able to connect to the port that is being configured. 

B. It informs the switch that traffic destined for MAC address 0018.DE8B.4BF8 should only be sent to the port that is being configured. 

C. It will act like an access list and the port will filter packets that have a source or destination MAC of 0018.DE8B.4BF8. 

D. The switch will shut down the port of any traffic with source MAC address of 0018.DE8B.4BF8. 

Answer:

Explanation: 

The first command configurs the maximum number of secure MAC addresses on a port to one. The next command specifies that MAC addresses that are allowed with port security; in this case it is just the one single device MAC. If any other device connects on that port the port will be shut down by the port security feature.