4.1.6 Practice, LESSON 4, Telecommunication week 4
Which of the following ports does NTP run on?
123 Explanation NTP runs on UDP port 123. HTTP operates on port 80. HTTPS traffic using TLS runs on port 443. FTP traffic runs on port 21.
Which of the following is the highest stratum level allowed?
15 Explanation Stratum Level 15 is the highest level allowed.
Which of the following services automatically creates and deletes host records when an IP address lease is created or released?
Dynamic DNS
Which of the following is the first place a computer looks at during the name resolution process?
HOSTS file
What are the small, rapid variations in a system clock called?
Jitter Explanation Jitter refers to small, rapid variations in a system clock. Dispersion measures how scattered the time offsets (in seconds) are from a given time server. Skew measures the difference (in hertz) between a clock's actual frequency and the frequency necessary to keep a more accurate time. Drift measures how quickly a clock's skew changes in hertz per second.
4.7.9
Practice Questions
Which of the following gives the same IP address to multiple servers and manually defines different routes on an IPv4 network?
BGP Explanation Anycast only works on IPv6 networks. We can use Border Gateway Protocol (BGP) on an IPv4 network to give the same IP address to multiple servers and manually define different routes. Anycast only works on IPv6 networks. The Internet Group Management Protocol (IGMP) is used to identify multicast group members. It can also forward multicast packets to the segments where group members reside. Multicast is used to send a message to a specific group of devices.
Which of the following will not function properly if there is a time mismatch error?
Security certificates Explanation If there is a time mismatch error, security certificates suspect malicious behavior and block connections. Event logging still functions properly if a system's time is off. Program installation and logging into Windows are not affected by time mismatch errors.
In this scenario, you would most likely need to configure the forward lookup zone. The forward lookup zone matches the hostname to the IP address. You wouldn't need to configure the reverse lookup zone since you can access the intranet site using the IP address. A reverse lookup zone matches the IP address to the hostname. Dynamic DNS (DDNS) enables clients or the DHCP server to update records in the zone database automatically. This occurs whenever an IP address lease is created or renewed. This is not necessary in this scenario. The CNAME record provides alternate names (or aliases) to hosts that already have a host record. Using a single A record with multiple CNAME records means that when the IP address changes, only the A record needs to be modified. This is not necessary in this scenario.
com
Which stratum level does the authoritative time device fall under?
0 Explanation Stratum 0 is the highest level in the hierarchy. Stratum 0 is the authoritative time device itself, such as a GPS time source or atomic clock. The higher the stratum number, the lower it is on the stratum hierarchy, and the less precedence it has in relation to other time providers with a lower number.
Based on the address prefix for each IPv6 address on the right, identify the address type from the list on the left. (Addresses may not represent actual addresses used in production.
2001:6789:9078::ABCE:AFFF:FE98:0001 Global unicast FD00::8907:FF:FE76:ABC Unique local FEA0::AB89:9FF:FE77:1234 Link-local FF00:98BD:6532::1 Multicast FF02::1:2 Multicast Explanation Based on previous standards, global unicast addresses start with 20, but they can now include any prefix that isn't reserved. Addresses beginning with FC or FD are unique local addresses. Addresses beginning with FE8, FE9, FEA, or FEB are link-local addresses. Addresses beginning with FF are multicast addresses. There are no broadcast addresses in IPv6.
4.8.3 Practice Questions
4.8.3 Practice Questions
Which of the following are valid IPv6 addresses? (Select two.)
6384:1319:7700:7631:446A:5511:8940:2552 141:0:0:0:15:0:0:1 Explanation An IPv6 address is a 128-bit address listed as eight 16-bit hexadecimal sections. Leading 0s can be omitted in each section. Therefore, 6384:1319:7700:7631:446A:5511:8940:2552 and 141:0:0:0:15:0:0:1 are both valid IPv6 addresses. A single set of all-zero sections can be abbreviated with two colons (::). So, 141::15:0:0:1 is also a valid address.
You manage a network with two locations (Portland and Seattle). Both locations are connected to the internet. The computers in both locations are configured to use IPv6. You'd like to implement an IPv6 solution to meet the following requirements: Hosts in each location should be able to use IPv6 to communicate with hosts in the other location through the IPv4 internet. You want to use a site-to-site tunneling method instead of a host-to-host tunneling method. Which IPv6 solution should you use?
6to4 tunneling Explanation Use 6to4 tunneling to create a router-to-router tunnel between two sites through an IPv4 network. Use Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) to enable IPv6 hosts to communicate over a private IPv4 network within a site. ISATAP doesn't work between sites. Use Teredo tunneling to configure a host-to-host tunnel between two hosts separated by symmetric NAT. Use 4to6 tunneling to allow IPv4 traffic on an IPv6 network.
Which of the following IPv6 addresses is equivalent to the IPv4 loopback address of 127.0.0.1?
::1 Explanation The IPv6 loopback address is ::1. The local loopback address isn't assigned to an interface. It can be used to verify that the TCP/IP protocol stack has been properly installed on the host. :: is the unspecified address (also identified as ::/128). The unspecified address is used when there's no IPv6 address. It's typically used during system startup, or when the host hasn't yet configured its address. The unspecified address shouldn't be assigned to an interface. Multicast addresses have an FF00::/8 prefix. FF02::/8 is the multicast prefix for all nodes on the local link.
Listed below are several DNS record types. Match each record type on the left with its function on the right.
A CNAME PTR AAAA MX
Which of the following allows the same IPv6 address to be assigned to multiple interfaces?
Anycast Explanation The anycast address is a unicast address that's assigned to more than one interface, typically ones that belong to different hosts. An anycast packet is routed to the nearest interface, having that address based on routing protocol decisions. Unicast transmissions are one-to-one communication between two devices. Unicast does not allow the same IPv6 address to be assigned to multiple interfaces. Multicast is used to send a message to a specific group of devices. Multicast does not allow the same IPv6 address to be assigned to multiple interfaces. A broadcast message sends data to all the hosts on the subnet. This does not allow the same IPv6 address to be assigned to multiple interfaces.
Which of the following works as an authoritative time device?
Atomic clock Explanation An atomic clock, or GPS time source, works as an authoritative time device. None of the other options are exact enough to be used as authoritative time devices.
Which access control model is based on assigning attributes to objects and using Boolean logic to grant access based on the attributes of the subject? Role-based access control (RBAC) Mandatory access control (MAC) Rule-based access control Attribute-based access control (ABAC)
Attribute-based access control (ABAC)
Which of the following BEST describes the special MAC address that multicast traffic frames are sent to?
Begins with 01-00-5E and ends with a form of the IP multicast group address Explanation Frames that contain multicast traffic are sent to a special MAC address. The MAC address begins with 01-00-5E. The last portion is a form of the IP multicast group address.
You want to implement a protocol on your network that allows computers to find a host's IP address from a logical name. Which protocol should you implement?
DNS
You need to enable hosts on your network to find the IP address of logical names, such as srv1.myserver.com. Which device should you use?
DNS server
You have a system that allows the owner of a file to identify users and their permissions to the file. Which type of access control model is implemented? Role-based access control (RBAC) Mandatory access control (MAC) Rule-based access control Correct Answer: Attribute-based access control (ABAC)
Discretionary Access Control (DAC)
If dynamic DNS is in use, which of the following events causes a dynamic update of the host records? (Select two.)
Enter the ipconfig /registerdns command on a workstation. Renew the DHCP server's IP address lease.
You want to implement an access control list in which only the users you specifically authorize have access to the resource. Anyone not on the list should be prevented from having access. Which of the following methods of access control should the access list use? Explicit allow, explicit deny Implicit allow, implicit deny Implicit allow, explicit deny Explicit allow, implicit deny
Explicit allow, implicit deny
Which of the following IPv6 addresses is used by a host to contact a DHCP server?
FF02::1:2 Explanation FF02::1:2 is the IPv6 address used to contact a DHCP server. All addresses with the FF00::/8 prefix are multicast addresses. IPv6 uses multicasts instead of broadcasts. FF02::2 is the multicast address for all routers on the local link; FF02::1 is for all hosts on the link. FE80::/10 is the prefix for link-local unicast addresses.
You are the network administrator for a small consulting firm. The firm has recently rolled out a new intranet site, and you are responsible for configuring the DNS. You are able to connect to the intranet site by using the IP address, but you cannot connect when you use the hostname. Which of the following do you need to configure so that the site can be accessed with the hostname?
Forward lookup zone
After implementing the National Institute of Standards and Technology (NIST) Cybersecurity Framework, the chief information security officer (CISO) is assessing the company's security posture to identify deficiencies from the framework's recommendations. What process can the CISO run to get a better sense of what the company needs to improve upon? Penetration test Implement disaster recovery plan Gap analysis Implement business continuity plan
Gap analysis
Consider the following IPv6 address: FD01:0001:0001:005::7/64 Drag the component parts of this address on the left to the corresponding descriptions on the right. (Not all descriptions on the right have corresponding components on the left.)
Global routing prefix = FD01:0001:0001:005 Subnet ID =:005 Interface ID = ::7 Prefix length =/64 Unique local unicast prefix= FD Explanation The IPv6 address FD01:0001:0001:005::7/64 is a unique local unicast address. As such, it's composed of the following component parts: Unique local unicast prefix: FD Global routing prefix: FD01:0001:0001:005 Subnet ID: 005 Interface ID: ::7 Prefix length: /64
You need to design an IPv6 addressing scheme for your network. The following are key requirements for your design: Infrastructure hosts, such as routers and servers, are assigned static interface IDs. However, workstations, notebooks, tablets, and phones are assigned interface IDs dynamically. Internet access must be available to all hosts through an ISP. Site-to-site WAN connections are created using leased lines. Which type of IPv6 addressing is most appropriate for hosts on this network?
Global unicast addressing Explanation You should use global unicast addressing in this scenario because internet access is required by network hosts. Global unicast addressing uses registered addresses and is equivalent to public addressing in IPv4. Because the addresses are registered with IANA, no other organization can use them on any public network, including on the internet. Unique local unicast addresses are private addresses used for communication within a site or between a limited number of sites. These addresses aren't registered with IANA and can't be used on a public network without address translation. Link-local addresses are assigned to all IPv6 interfaces on the network by default, but they can only be used on the local subnet. Routers never forward packets destined for local-link addresses to other subnets. Anycast addresses are used to locate the nearest server of a specific type. For example, this could be the nearest DNS or network time server.
Which protocol does an IP host use to inform a router that it wants to receive specific multicast frames?
IGMP Explanation IP hosts use IGMP (Internet Group Management Protocol) to inform multicast-enabled routers that they want to receive specific multicast frames. ICMP notifies routers of problems on the network and of undeliverable packets. SNMP (Simple Network Management Protocol) lets network administrators set up alerts to monitor the state of a network. SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used to send email.
Which of the following are characteristics of Teredo tunneling? (Select three.)
Is configured between individual hosts Can be used to send data over the internet Has dual-stack hosts Explanation Teredo tunneling has the following characteristics. It: Is configured between individual hosts. Each host handles the encapsulation and de-encapsulation process. Uses dual-stack hosts and performs IPv6 tunneling to send data on an IPv4 network. Can be used to send data over the internet. Miredo tunneling is the Teredo tunneling equivalent used on Linux systems.
You have a server at work with a custom application installed. Connections to the server that use the custom application must use IPv6, but the server is currently running IPv4. You're the only person who connects to the server, and you always use your Linux laptop for the connection. Your laptop supports both IPv4 and IPv6, but the rest of your company network runs only IPv4. You need a cost-effective solution to allow your laptop to connect to the server. Your solution must also support communication through NAT servers. Which client software should you use to connect to the server?
Miredo Explanation On Linux, Miredo client software is used to implement Teredo tunneling. Teredo tunneling establishes a tunnel between individual hosts. Hosts must be dual-stack hosts so that they can tunnel IPv6 packets inside of IPv4 packets. Teredo works with NAT. ISATAP and 6to4 tunneling both require at least one router. You only need to tunnel between two individual computers. 4to6 tunneling is used to send IPv4 traffic through an IPv6 network by encapsulating IPv4 packets within IPv6 packets.
Which of the following address types shares multiple hosts and groups of computers that receive the same data stream?
Multicast Explanation A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address. A unicast address is an address that identifies a single host. A broadcast address is an address that's sent to all hosts. Broadcast traffic is typically only forwarded with one subnet, but not between two. A half-duplex address uses a separate channel for sending and receiving, but the channels are shared by multiple devices and can only be used by one single device at a time.
Which type of address is the IP address 232.111.255.250?
Multicast Explanation The address 232.111.255.250 is a multicast address. A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address, and multicast addresses are in the range of 224.0.0.0 to 239.255.255.255. A unicast address is an address that identifies a single host. A broadcast address is an address that is sent to all hosts. Broadcast addresses are the last possible address on a subnet (typically ending in 255). The private IPv4 address ranges are: 10.0.0.1 to 10.255.255.254 172.16.0.1 to 172.31.255.254 192.168.0.1 to 192.168.255.254
Which address type do people use to support video conference calls consisting of multiple participants?
Multicast Explanation Unified communication (UC) systems typically use unicast network transmissions. An example of a unicast transmission is a one-on-one VoIP phone call. UC systems also support multicast transmissions. Examples of a multicast transmission are conference phone calls or video conference calls consisting of multiple users. The anycast address is a unicast address that's assigned to more than one interface, typically belonging to different hosts. The local loopback address for the local host is 0:0:0:0:0:0:0:1 (also identified as ::1 or ::1/128).
Which of the following principles is implemented in a mandatory access control model to determine object access by classification level? Separation of duties Clearance Ownership Principle of least privilege Need to know
Need to know
You are a cybersecurity expert implementing a zero trust model in a large organization. You are tasked with designing the control and data planes. Which of the following strategies should you prioritize and why?
Neither, focus on the application plane to ensure that applications are secure and function properly. Prioritize the data plane to ensure that data traffic flows securely and efficiently across the network. Focus on the control plane to ensure that all network devices are properly configured and managed. Correct Answer: Balance your focus between the control and data planes, ensuring both are optimized for security and efficiency.
Which of the following best describes NTP efficiency?
One packet per minute is necessary to sync two machines to an accuracy of within a millisecond of one another. Explanation NTP is very efficient. Only one packet per minute is necessary to synchronize two machines to an accuracy of within a millisecond of one another.
A corporation's IT department is integrating a new framework that permits, ascertains, and applies various resources in accordance with established company policies. Which principle should the department incorporate? Policy-driven access control Zero trust AAA Authorization models
Policy-driven access control
What is the primary purpose of separation of duties? Grant a greater range of control to senior management. Increase the difficulty of performing administrative duties. Prevent conflicts of interest. Inform managers that they are not trusted.
Prevent conflicts of interest.
What is the process of a DNS server asking other DNS servers to perform name resolution known as?
Recursive lookup
You have implemented an access control method that only allows users who are managers to access specific data. Which type of access control model is being used? Discretionary access control (DAC) Mandatory access control (MAC) Discretionary access control list (DACL) Role-based access control (RBAC)
Role-based access control (RBAC)
Which of the following is an example of rule-based access control? A computer file owner who grants access to the file by adding other users to an access control list. A subject with a government clearance that allows access to government classification labels of Confidential, Secret, and Top Secret. A member of the accounting team that is given access to the accounting department documents. Router access control lists that allow or deny traffic based on the characteristics of an IP packet.
Router access control lists that allow or deny traffic based on the characteristics of an IP packet.
You are the network administrator for a small consulting firm. You've set up an NTP server to manage the time across all the machines in the network. You have a computer that's experiencing a slight time drift of just a few seconds. Which time correction should you use to fix the system's clock?
Slew Explanation If time is off by just a few seconds, slewing is better for putting it back on track. Slewing is a slower, methodical method of correcting the time, but the risk of problems occurring is much less. Slamming is used if the time is off by quite a bit and slewing will take too long. While this is a quick and immediate fix, slamming can cause some programs to function improperly. Jitter refers to small, rapid variations in a system's clock. Skew measures the difference (in hertz) between a clock's actual frequency and the frequency necessary to keep a more accurate time.
You manage a network that uses IPv6 addressing. When clients connect devices to the network, they generate an interface ID and use NDP to learn the subnet prefix and default gateway. Which IPv6 address assignment method is being used?
Stateless autoconfiguration Explanation With stateless autoconfiguration, clients automatically generate an interface ID and learn the subnet prefix and default gateway through Neighbor Discovery Protocol (NDP). With static full assignment, the entire 128-bit address and all other configuration information is statically assigned. Static partial assignment generates the interface ID from the MAC address, and clients are statically assigned the prefix. Stateful DHCPv6 is when the DHCP server provides each client with an IP address, default gateway, and other IP configuration information.
Which IP address do broadcast messages use?
The last valid IP address on the subnet Explanation We use broadcast messages to send data to all the hosts on the subnet. The last IP address on the subnet is reserved for broadcast messages. The first valid IP address on a subnet is reserved for the network ID. 224.0.0.1 is used for the query messages from routers. The 224.0.0.0 address range is reserved for local subnets.
What is it called when a system's clock begins to be off by a few seconds or even minutes?
Time drift Explanation Time drift is when a system's clock begins to be off by a few seconds or minutes. Using Network Time Protocol (NTP) can help reduce the risk of time drift. Slewing is an NTP correction method where the time is adjusted a few milliseconds at a time until it's correct again. Slamming is an NTP correction method where the time is hard reset to the correct time. Dispersion measures how scattered the time offsets (in seconds) are from a given time server.
You are the network administrator for a consulting firm. A website that users on your network visit has a habit of frequently changing its IP address. When these IP mappings change, users are unable to connect until you clear the DNS cache. Which of the following settings should you configure so that the cache does not need to be manually cleared every time?
Time to live
Which of the following time standards does NTP use?
UTC Explanation Network Time Protocol (NTP) uses Coordinated Universal time (UTC) instead of time zones. Each device is responsible for converting the time to the local time zone. The other options are United States time zones: EDT = Eastern Time PDT = Pacific Time CDT = Central Time
Which type of address identifies which single host to send a packet to?
Unicast Explanation A unicast address is an address that identifies a single host. A broadcast address is an address that's sent to all hosts. Broadcast traffic is typically only forwarded with one subnet, but not between two. A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address. Simplex communication uses a single channel for both sending and receiving.
Which type of address is the IP address 198.162.12.254/24?
Unicast Explanation The IP address 198.162.12.254 is a unicast address that identifies a single host on the 198.162.12.0 subnet. 198.162.12.255 is the broadcast address for the subnet. Multicast addresses are in the range of 224.0.0.0 to 239.255.255.255. The private IPv4 address ranges are: 10.0.0.1 to 10.255.255.254 172.16.0.1 to 172.31.255.254 192.168.0.1 to 192.168.255.254
