2.0 Networking - A+ 1101 Flashcards

Question

31. When troubleshooting a network connectivity issue, you discover that the local computer has an IPv4 address of 169.254.2.2. What do you immediately know about this local computer? A. It is working fine. B. It can’t find a DHCP server. C. It isn’t on the network. D. It has an invalid IP address.

Answer 1

31. B. The 169.254.0.0/16 range in IPv4 is the automatic private IP addressing (APIPA) range. APIPA comes into play when the host is unable to locate a Dynamic Host Configuration Protocol (DHCP) server, and the network connection is configured to acquire an IP address dynamically. Since the computer is unable to get a dynamic IP address from the DHCP server, the operating system automatically assigns a random IP address in the APIPA range.

Answer 2

32. C. An IPv6 address in the FE80::/10 range is called a link-local address and is similar to an IPv4 automatic private IP addressing (APIPA) address. (The 169.254.0.0/16 range in IPv4 is the APIPA range, used for automatic configuration if the host can’t locate a Dynamic Host Configuration Protocol [DHCP] server.) Link-local addresses are generated by the PC when it boots up. Packets using a link-local address cannot be forwarded by a router

Answer 3

33. D. Universal Plug and Play (UPnP) is a standard designed to simplify the process of connecting devices to a network and to enable those devices to automatically announce their presence to other devices on the network. In a truly secure environment, UPnP would be disabled, but it is often left enabled on home networks. Dynamic Host Configuration Protocol (DHCP) automatically assigns an IP address to a device when it is powered on, attached to a network, and configured to obtain an address dynamically. Network address translation (NAT) is a feature of routers used to hide the IP addresses of computers on the local network side of the router from the other networks and computers on the outside of the network. Quality of Service (QoS) can be configured to give desired devices preference over others for using network bandwidth.

Answer 4

4. A, C. Addresses in the FE80::/10 range are link-local unicast addresses. A link-local address is assigned to each IPv6 interface but is not routable on the Internet. If this is the only address the host has, it will not be able to get on the Internet.

Answer 5

35. A. The File Transfer Protocol (FTP) is optimized for downloading files from servers. It uses port 21. Secure Shell (SSH) uses port 22, Telnet uses port 23, and Hypertext Transfer Protocol (HTTP) uses port 80.

Answer 6

36. D. The Lightweight Directory Access Protocol (LDAP) is a directory services protocol based on the X.500 standard. LDAP is designed to access information stored in an information directory typically known as an LDAP directory or LDAP database. This often includes employee phone numbers and email addresses. Simple Network Management Protocol (SNMP) is used in network monitoring, Simple Mail Transfer Protocol (SMTP) is used in sending email, and Common Internet File System (CIFS) is a filesystem for providing shared access between diverse clients.

Answer 7

40. C. Fiber-optic broadband Internet offers fast speeds (often in the 1–2 Gbps range) but is also the most expensive. Cable may have download speeds up to 1 Gbps (typically 10 to 500 Mbps), but upload speeds are typically only around 5 to 50 Mbps, while fiber-optic upload speeds may be in the 1 Gbps range. Digital Subscriber Line (DSL) uses plain old telephone service (POTS) lines and is slow. Satellite networks can be faster than DSL, but still only offer speeds up to about 150 Mbps.

Answer 8

41. A, B. IPv4 specifies private (nonroutable) IP address ranges for each class as follows: Class A: 10.0.0.0 to 10.255.255.255, Class B: 172.16.0.0 to 172.31.255.255, and Class C: 192.168.0.0. to 192.168.255.255. Other nonroutable numbers are 127.0.0.1, which is the loopback address, and 169.254.0.0 to 169.254.255.255, which is the automatic private IP addressing (APIPA) range. Class A addresses have a first octet from 0 to 127. Class B’s first octet ranges from 128 to 191. Class C’s first octet ranges from 192 to 223.\ Numbers above Class C are reserved.

Answer 9

42. C. Server Message Block (SMB) is a protocol used to provide shared access to files, printers, and other network resources. It originally ran on NetBIOS over UDP using ports 137/138 and over TCP using ports 137 and 139, but it’s now part of the TCP/IP stack and uses port 445. Running on NetBIOS allows SMB to facilitate file sharing on a single network, while being part of TCP/IP allows it to facilitate file sharing across the Internet. By itself, SMB is not secure, so it needs other network appliances or software to secure the data being sent over its port(s). File Transfer Protocol (FTP) uses ports 20/21, Secure Shell (SSH) uses port 22, and Simple Network Management Protocol (SNMP) uses ports 161/162.

Answer 10

43. A. All of the answer choices are communications protocols for sharing resources. The Common Internet File System (CIFS) is Microsoft’s version of Server Message Block (SMB.) Once upon a time CIFS was used extensively for file sharing over a network, but it has since fallen out of favor. While CIFS and SMB both facilitate file sharing, SMB does it better and has other features as well. Samba and Network File System (NFS) facilitate sharing files between clients and servers in Linux distributions. Samba will allow mixed environments with both Windows and Linux machines to share files. NFS will not.

Answer 11

44. B, D. Each IPv6 interface can and often does have multiple addresses assigned to it. IPv6 is backward compatible with IPv4 by using tunneling, dual stack, or translation. IPv6 uses multicast addresses in place of broadcast addresses, and a link-local address is established either automatically when a computer boots up or by manually configuring it, but either way the link-local address must be present

Answer 12

45. B. Hubs were once used extensively in Ethernet networks, but they have fallen out of favor because they have a large disadvantage when compared to switches. A hub forms a single collision domain with all of their ports. On a switch, each port is its own collision domain. A switch keeps a table of its ports and the media access control (MAC) address that can be reached from each port. A switch will only forward a packet to a specific port, whereas a hub will forward a packet to all of its ports. The exception is that a broadcast packet will be sent to all switch ports. Switches are faster and more accurate than hubs and are used almost exclusively as the connectivity device within a local area network (LAN.)

Answer 13

46. B. The Trivial File Transfer Protocol (TFTP) is a very simple connectionless protocol. It has little overhead, meaning that it doesn’t take much memory to run it. This makes it perfect for booting a thin client across a network. It can be used to transfer the needed boot files to devices that don’t have hard drives. It should not be used to transfer files across the Internet because it is not secure. File Transfer Protocol (FTP) is more robust than TFTP. File Transfer Protocol Secure (FTPS) is a secure version of FTP. Simple Mail Transfer Protocol (SMTP) is used to send email messages.

Answer 14

47. B. 127.0.0.1 is the IPv4 loopback address, used to ping the local network interface. The IPv6 equivalent is ::1.

Answer 15

48. D. If you need to trace a wire in a wall from one location to another, a tone generator and probe is the right tool to use. To use it, attach one end to one end of the cable, such as the end at the computer. Then go to the patch panel with the other end of the probe to locate the cable. These tools are lifesavers when the cables are not properly labeled. A cable tester is used to confirm the integrity of a cable and verity that it is wired correctly. A loopback plug is used to test a network interface card (NIC,) and a punchdown tool is used to terminate wires into a patch panel.

Answer 16

49. B. Dynamic Host Configuration Protocol (DHCP) dynamically assigns IP addresses and other IP configuration information to network clients. The Domain Name System (DNS) translates human-readable names to their associated IP addresses, the Remote Desktop Protocol (RDP) allows a user to access a computer remotely as if they were sitting there, and Lightweight Directory Access Protocol (LDAP) is used for retrieving information from a database.

Answer 17

50. B. Switches provide centralized connectivity for a LAN. Switches examine the header of incoming packets and forward each to only the port whose associated media access control (MAC) address matches the receiving MAC address in the header. Hubs are seldom used now because the entire hub is one collision domain and when a packet is received, the hub sends the packet out to all of its ports indiscriminately. Bridges are used to connect different networks to work as one, and routers are used to forward packets from one network to other networks.

Answer 18

51. B. Email is pushed from clients to servers using the Simple Mail Transfer Protocol (SMTP). SMTP uses port 25. When trying to remember if SMTP is sending or receiving email, think S for Send. Port 23 is used by Telnet, now considered insecure and obsolete. Port 110 is used by POP3 (Post Office Protocol 3), and port 143 is used by IMAP (Internet Mail Access Protocol), both of which are used to retrieve email.

Answer 19

52. C. Of the Wi-Fi standards listed, 802.11n has the longest range by default, at roughly 70 meters indoors and 250 meters outdoors. 802.11ac is newer and faster than 802.11n, but it transmits exclusively in the 5 GHz range, which restricts its functional distance. 802.11a, which is legacy and uses the 5 GHz frequency range, could only send a signal about 30 meters, and 802.11g, which is also legacy but uses the 2.4 GHz frequency range, could only send a signal about 50 meters.

Answer 20

54. C. Hubs send every communication they receive out every connected port. Switches will send broadcast packets out every port, but otherwise will send packets to a specific port based on the MAC address. A router will not forward any broadcast packet; therefore a router is the boundary of an IPv4 broadcast domain. A modem (modulator/demodulator) converts signals from one type to another, such as from an analog signal to a digital one.

Answer 21

55. A. Simple Network Management Protocol (SNMP) gathers and manages network performance information. A management device called an SNMP server can be set up to collect data from these devices (called agents) and ensure that your network is operating properly. SMTP is a mail protocol, LDAP is for accessing database information, and SMB is for file sharing.

Answer 22

56. C. Although Digital Subscriber Line (DSL) is being dropped by some providers in favor of fiber-optic lines, it is still a viable Internet connectivity solution in rural areas that fiber has not yet reached. DSL utilizes existing phone lines and provides fairly reliable access while carrying voice and data on the same lines. Most DSL subscriptions are asymmetrical, meaning they offer faster download speeds than upload speeds. POTS stands for Plain Old Telephone Service, an acronym from dial-up days. Cable connectivity is provided by cable TV companies. ISDN is Integrated Services Digital Network, a now obsolete technology that allowed voice and data communication on the same existing telephone lines, similar to DSL.

Answer 23

57. C. When setting up wireless access points, it’s good practice to have their ranges overlap to ensure that there is no loss of communication when roaming in the network’s area. However, to avoid problems, it’s best to set up the access points with nonoverlapping channels; in this way, the overlapping ranges ensure continuous signal coverage while the nonoverlapping channels avoid interference from one WAP to another in the overlapping areas.

Answer 24

60. B. The 802.11ac standard has an indoor range of approximately 35 meters. At a minimum, you will need three access points. Depending on coverage and indoor interference, such as thick walls, you might need more.

Answer 25

62. D. The cable can be any of the three major types, coaxial, twisted pair, or fiber, but it needs to be plenum rated. Normal cables have a PVC coating, which produces a poisonous gas when burned. Plenum-rated cables have a Teflon coating, which is not toxic when burned.

Answer 26

64. C. The private IP address ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. The address 172.168.38.155 is outside the private IP address range and is a public (routable) address

Answer 27

67. C. 802.11b/g transmits in the 2.4 GHz frequency, as does 802.11n, so they are compatible. The newer 802.11ac is a 5 GHz standard and therefore is not backward compatible with 802.11b/g. 802.11ax transmits in both the 2.4 GHz and 5 GHz frequencies, up to 7 GHz. 802.11r is not a standard related to Wi-Fi speed and is not in the A+ exam objectives.

Answer 28

65. A. By configuring Quality of Service (QoS), an administrator can set different priorities for one or more types of network traffic based on different applications, data flows, or users. UPnP allows devices to identify and connect to other devices on a network. A screened subnet is a secure area established using a router or routers to protect an internal network from traffic coming to a web-facing server. Port forwarding is configured on a router to send specific traffic to a specific device on a network.

Answer 29

69. A. A subnet mask of 255.255.224.0 has 8 bits in each of the first 2 octets set to on, and it has 3 bits in the third octet on. Therefore, it corresponds to /19 in shorthand. In the binary number system (base two), each bit has two possible values, 0 or 1. Each bit in an octet going from right to left increments by an exponent of two, making the bits of the octets worth the decimal values as follows: | 128 |64 |32 |16 | 8 | 4 | 2 | 1 |. Bits for the subnet mask are always used from left to right, so one bit would be equal to a decimal value of 128. Two bits would be equal to a decimal value of 192 (128 + 64). Three bits would be equal to a decimal value of 224 (128 + 64 + 32), and so on. When all 8 bits of the octet are used for the subnet mask, the equivalent decimal value is 255. For this example, the first 2 octets (8 bits each) are completely on, and in the third octet, only 3 bits are on, making a total of 19 bits in the subnet mask turned on to indicate the network number (8 + 8 + 3 = 19).

Answer 30

71. A, B. No two nodes on any network, whether IPv4 or IPv6, can have the same IP address because the host portion (or interface ID) of the IP address is what identifies the individual computer on the network. If the network has some machines manually configured, which is generally done with servers, and the remainder of the computers are configured to use Dynamic Host Configuration Protocol (DHCP), you would need to ensure that the manually configured numbers are outside of the DHCP scope (the numbers the DHCP server will automatically assign) but within the bounds of the network. For example, in an IPv4 network, if the network number is 200.100.1.0, the router, which is also acting as a default gateway, might be assigned 200.100.1.1, and numbers from 200.100.1.2 through 200.100.1.20 could be reserved for static configuration on devices that need an IP address that does not change. The DHCP scope would need to not include those numbers. If the network needed an available 180 IP addresses, then 200.100.1.21 to 200.100.1.200 could be safely assigned to the DHCP scope, avoiding any IP address duplication.

Answer 31

70. B. To communicate on an IPv4 network, a host must be configured with a valid IP address and a subnet mask. A default gateway is needed only if the host will connect to a remote network. DNS servers are optional but useful, because they resolve hostnames to IP addresses.

Answer 32

72. B, C. Certain devices on a network, such as printers and servers, should have an IP address that doesn’t change (static) so that the other nodes on the network can always find the device. Option A is incorrect because if the DHCP lease on the IP address expires, the print server would be assigned a different IP address the next time it logs in. A static IP could be configured on the printer server, or the IP address could be configured as reserved on the DHCP server for that print server. Either choice would work. Static and dynamic IP addresses almost always exist on the same network, because each is needed to have a network that runs smoothly.

Answer 33

73. D. Wired Equivalent Privacy (WEP) was one of the first security standards for wireless devices. It uses a static key; the keys are commonly 10, 26, or 58 hexadecimal characters long. WEP was depreciated in 2004 because it was no longer secure and was replaced temporarily by WPA, which was quickly replaced by WPA2. ' WPA3 is the current and most secure standard.

Answer 34

74. D. Simple Network Management Protocol (SNMP) uses UDP port 161. User Datagram Protocol (UDP) is considered connectionless, so it does not guarantee delivery of data packets and has a lower network overhead than Transmission Control Protocol (TCP), a connection oriented protocol, does. Port 143 is used for IMAP

Answer 35

75. B. Clients are unable to get to the DNS server, which resolves hostnames (or URLs) to IP addresses. DNS uses port 53. Ports 20 and 21 are used for File Transfer Protocol (FTP). Ports 67 and 68 are used by Dynamic Host Configuration Protocol (DHCP). Port 80 is used for Hypertext Transfer Protocol (HTTP), and port 443 is HTTP Secure (HTTPS).

Answer 36

79. D. Satellite Internet is not much like any other type of broadband connection. Instead of a cabled connection, it uses a satellite dish to receive data from an orbiting satellite and relay station that is connected to the Internet. Because it requires a clear line of sight between the transmitter and receiver, it can be referred to as “line of sight” wireless. Mobile hotspot (cellular) devices are also an option, but they may not be able to reach the speed of a satellite connection and they depend on a strong cellular signal. For an installation far from civilization (and cell towers), satellite may be the only option. Cable, DSL, and fiber rely on lines that would not run as far as a forest ranger lookout tower.

Answer 37

77. C. Normal (unsecured) websites are accessed on port 80, which is the port that Hypertext Transfer Protocol (HTTP) uses. Shut it down, and no one will be able to access websites, except secure sites that use HTTPS, which is on port 443.

Answer 38

80. C. Wireless Internet Service Providers (WISPs) use fixed wireless technology, which requires antennas to send radio waves between your location and a fixed hub on a tower or other tall structure similar to a cellular tower. Download speeds can be up to 1 Gbps. Satellite is an option in very remote areas but has the latency involved with traveling thousands of miles between the connection to the satellite and back again. Digital Subscriber Line (DSL) uses telephone lines to create an Internet connection, but many carriers no longer offer DSL. A cellular hotspot can be used in many remote locations but depends on connection to a cellular tower and is not as fast as satellite

Answer 39

81. C. The two host-to-host protocols are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). TCP guarantees packet delivery through the use of a virtual circuit and data acknowledgments, and UDP does not. Because of this, TCP is often referred to as connection-oriented, whereas UDP is connectionless. IP and ICMP are not considered hostto-host protocols.

Answer 40

83. A, B. 802.11a and 802.11g provide throughput that is only 54 Mbps, 802.11n (Wi-Fi 4) provides throughput over 100 Mbps (theoretically up to 300 Mbps), but 802.11ac (Wi-Fi 5) and 802.11ax (Wi-Fi 6) have far surpassed these standards with throughputs, over 1 Gbps and multiple Gbps, respectively.

Answer 41

84. B, D. 802.11ac operates in the 5 GHz frequency only. 802.11g is only 2.4 GHz. 802.11n and 802.11ax operate in both frequencies.

Answer 42

85. C. NetBIOS over TCP/IP (NetBT) is for older applications still reliant on NetBIOS, the legacy network protocol intended for very small networks. NetBT lets such applications communicate over TCP/IP. Trivial File Transfer Protocol (TFTP) is a basic connectionless protocol that allows file transfer functions without user interaction. Hypertext Transfer Protocol Secure (HTTPS) is a secure connection-oriented protocol that runs over port 443

Answer 43

89. B. The distance for Power over Ethernet (PoE) is limited by the maximum distance set by the Ethernet cabling: 100 meters (328 feet). The power injector, the device that sources the electrical power to certain wires in the cable, can be as much as 100 meters from the powered device. The injector also needs to have sufficient power to match device needs, and devices must be compatible. PoE devices such as powered switches can provide a few watts or well over 100 watts, depending on the device.

Answer 44

86. C. An unmanaged switch will simply perform the basic task a switch should do: direct network traffic out the correct destination port. Prioritizing traffic, configuring virtual LANs (VLANs), and mirroring ports are all jobs that are done using managed switches.

Answer 45

91. C. The end-user devices are configured to at least request a DHCP-assigned IP address or they are preconfigured with a static IP, gateway, subnet mask, and DNS information.

Answer 46

92. D. MAC address filtering uses the physical address of a NIC to determine whether or not to allow a device to connect to the router. Disabling the SSID will hide the network from neighbors, but it won’t keep them from connecting if they discover the network. Port forwarding redirects requests for a specific port to a specific device on the network. The DHCP scope can be set up to only allow five machines to connect, but it may not be the right five machines.

Answer 47

96. D. A web server consists of hardware and software used to provide information to remote clients via the Internet. The main protocols for web servers are HTTP and HTTPS, but they can use other protocols as well. File Transfer Protocol (FTP) servers are used for downloading files quickly, and while they may have a graphical user interface (GUI), they have much less overhead than a web server. Proxy servers are a security measure between an internal user and the web and are used to monitor and filter information going into or out of a network. File servers are often used on a LAN to provide access to the same files by multiple users.

Answer 48

98. C. The file server is a centralized repository for users, typically company employees. File Transfer Protocol (FTP) servers are used for downloading files quickly, and while they may have a graphical user interface (GUI), they have much less overhead than a web server. Proxy servers are a security measure between an internal user and the web, and they are used to filter information going into or out of a network, whereas web servers may provide information about a company or its products to the general public

Answer 49

99. B. Proxy servers act as a gateway through which Internet access requests are handled, monitored, and, if need be, filtered. File Transfer Protocol (FTP) servers are used for downloading files quickly, and while they may have a graphical user interface (GUI), they have much less overhead than a web server. File servers are often used on a LAN to provide access to the same files by multiple users, whereas web servers may provide information about a company or its products to the general public.

Answer 50

101. C. A print server can be either a physical device or software configured on a computer. The print server provides centralized availability of print services to authorized users on the network. It accepts print jobs, and the documents are printed according to order of receipt or some configured priority. A syslog server gathers event information from devices on a network, creating a central repository for a network administrator to monitor and respond to events. A DNS server resolves domain names to IP addresses, and an authentication server verifies identity before allowing access to a network.

Answer 51

100. A. The File Transfer Protocol (FTP) server hosts files for easy access, allowing users to browse it and download and upload files. Proxy servers monitor and filter traffic into and out of a network. File servers are a repository of files accessed by multiple users on a network. A DNS server resolves human-readable names such as Wiley.com to an IP address

Answer 52

104. A. The syslog server operates with the Syslog protocol, which is used by many different operating systems and devices. These system-generated messages vary from the mundane “System started” to critical alerts. DNS servers resolve domain names to IP addresses. Print servers facilitate and manage printing by multiple users to one or more printers on a network, and authentication servers verify identity before granting access to a resource

Answer 53

102. B. If a user types www.sybex.com into a web browser, the Domain Name System (DNS) server will resolve the domain name to an IP address. Similarly, DNS servers will resolve a fully qualified domain named (FQDN) network directory resource on the network to make locating that resource possible. Syslog servers provide a repository of events on the network to aid in network management. Print servers provide and manage access to one or more printers by multiple users on a network, and an authentication server verifies identity before granting access to resources on a network.

Answer 54

103. D. The authentication server facilitates the challenge/response service for validating someone’s credentials. Syslog servers provide a repository of events on the network to aid in network management. DNS servers resolve URLs to IP addresses, and print servers provide and manage access to one or more printers by multiple users on a network.

Answer 55

106. C, D. Connection-oriented protocols work over TCP, which guarantees delivery of packets. This guarantee requires greater resources than UDP, which is connectionless, therefore not requiring that a packet be resent if not received. HTTPS and SSH are connection-oriented protocols, whereas Trivial File Transfer Protocol (TFTP) and DHCP are connectionless protocols.

Answer 56

107. B. An intrusion detection system (IDS) will monitor and alert you on suspect behavior. The IDS can be a network-based device or host-based, meaning it runs as a process in the background. Proxy servers are used to control traffic into and out of a network. Unified Threat Management (UTM) provides multiple security features on a single appliance. ATM (Asynchronous Transfer Mode) has to do with transferring different types of traffic (i.e., voice and data) over the same communication lines at the same time.

Answer 57

108. D. The intrusion detection system (IDS) will alert on suspect activity, but it will not react or actively attempt to block the activity. The intrusion prevention system (IPS), however, should attempt to block the activity.

Answer 58

109. C. Unified Threat Management (UTM) systems can be hardware networking devices, virtual devices, or an off-premises service. UTM’s role is to combine several security features and services into a single device, allowing for easier management and compatibility. IDSs (intrusion detection systems) will only notify an admin if a threat is detected. Intrusion protection systems (IPSs) will detect and respond to security threats. UTP is unshielded twisted pair, a type of network cabling

Answer 59

110. A, D. A Simple Network Management Protocol (SNMP) trap is unrequested information being sent from an SNMP agent, in this case running on a managed switch. SNMP traps are sent via port 162.

Answer 60

111. B. Cellular is the only type of network connection that allows for the type of mobility that this photographer needs. A cellular hotspot device from a mobile provider would work well. Satellite would require repositioning of the dish on a regular basis and may not work well because of obstructions. WISP requires being within a few miles of a tower and line of-sight between the antenna and tower, so that wouldn’t work well either. DSL requires a stationary phone line.

Answer 61

112. C. Cable Internet service requires a cable modem to separate the Internet signal from TV channels and to convert the signal into one that your computer can use. A switch is used on a LAN as a central connection point. A hub for networking is an obsolete device that would send any signal it received out of all of its ports. A cable multiplexer connects several signals into one for transmission over a cable, such as input from multiple security cameras.

Answer 62

116. B. Virtual LANs, or VLANs, will segment your network into smaller broadcast domains. Multiple VLANs can exist on the same physical switch. Traffic is isolated to only the paths determined by how you have identified VLANs on your managed switches. A VPN (virtual private network) uses tunneling protocols to secure a private connection across a public network. A UPS (uninterruptable power supply) is a battery backup with other features used to maintain power to a device when the main power goes down, and SQL (Structured Query Language) is used to retrieve information from a database.

Answer 63

118. C. Wireless LAN (WLAN) networks commonly have three types of nodes: a client, a router, and a gateway. They typically don’t include a server and often are of fluid nature, where devices come and go as needed. They may include a printer. A WLAN can be used to connect wireless users to a wired network

Answer 64

119. A, B. A NIC can be configured either with a specific (static) IP address, or to obtain an IP address from an available Dynamic Host Configuration Protocol (DHCP) server. Many routers have the capability to provide DHCP services. When a device with a properly configured NIC attempts to join a network, a request for an address will be sent to the DHCP server, and the DHCP server will lease an address to that device, if one is available.

Answer 65

120. B. Option B, 2601::0f:ab:cd:123:4a, and the address in the question both have a subnet of 0f. IPv6 addresses consist of 128 bits, divided by colons (:) into 8 hextets. Therefore, each hextet represents 16 bits. Leading 0s can be omitted, and in one place in each address, consecutive groups of 0s can be omitted, represented by double colons (::). The last 64 bits (4 hextets) of an IPv6 address are the Interface ID, identifying the unique computer. The first 64 bits are called the prefix. ISPs and very large organizations are assigned /48 prefixes. The next 16-bits (the fourth hextet) are used to define subnets. Option A has a fourth hextet of 0. Option C is a link-local address. Option D is an invalid number because hex numbers only go to letter f.

Answer 66

121. B. The third octet’s subnet mask of 192 means that the first 2 bits of the octet are used to identify the network number, so the network can be broken down into four subnets using those first 2 bits of the octet. The subnets would be 00000000, 01000000, 10000000, and 11000000. IP addresses within each range would be 0 to 63, 64 to 127, 128 to 191, and 192 to 255. The first and last IP in each range would not be used because they would represent the subnet itself and the broadcast numbers. Options A, C, and D all fall in the second subnet’s range. Option B is in the third subnet.

Answer 67

122. A. The PoE standards are IEEE 802.3af (PoE), 802.3at (PoE+), and 802.3bt (PoE++). A main difference between the standards is how much power per port can be provided. 802.3af can supply up to 15.4 watts per port, 802.3at can provide up to 30 watts per port, and 802.3bt can provide 60 watts (Type 3) or 100 watts (Type 4). The power that actually reaches the devices is less due to voltage loss over distance. 802.3b is a legacy broadband Ethernet standard. 802.11 and802.11ax are Wi-Fi standards.

Answer 68

123. B, C. PoE devices providing power are backward compatible with older devices, meaning that while 802.3bt is rated at 60W for Type 3 and 10W for Type 4, an 802.3bt device will work with an 802.3at (Type 2) device. Option A would not provide enough power for your friend’s device. Option D is a Wi-Fi standard, not a PoE standard.

Answer 69

124. B, D. ONT (optical network terminal) is installed by a fiber-optic ISP, and it’s typically a small box on an outside wall. The terminal is a transducer, converting between copper/ electrical signals and fiber-optic/light signals. It does require power, and the terminal may have an indicator light to signal whether it is receiving power.

Answer 70

127. C. A wireless LAN (WLAN) would be the best solution for this office. A WLAN is a group of devices in the same location that communicate via radio waves instead of cables. WLANS can have multiple wireless access points (WAPs), preferably overlapping so that users won’t experience signal drop. Wi-Fi is a type of WLAN. A LAN is incorrect because it would require disconnecting and reconnecting cables in each room. A VLAN (virtual LAN) is established using security protocols to segregate a network. WAN is incorrect because this is a network in a single office, not geographically distant computers.

Answer 71

125. C. Software-defined networking (SDN) has many advantages over traditional networking. It can work with virtual and physical networks using SDN-compatible devices, providing centralized control of the entire network and the ability to reconfigure networks often without having to physically touch a router or switch.

Answer 72

126. B. Frequencies for wireless Internet service providers (WISPs) can be licensed or unlicensed. (The FCC is the licensing body.) Most WISPs use the unlicensed frequencies because they are free to use.

Answer 73

130. B. A fileshare server handles requests from fileshare clients for access to data stored on the server. The fileshare server resides on the same machine as the data. A client access license (CAL) is a license allowing one machine to connect to a server, and SAN is a storage area network, both of which are unrelated to the question

Answer 74

128. C. A storage area network (SAN) is a high-speed network whose purpose is to provide fast access by servers to storage. Network attached storage (NAS) differs from a SAN in that it is not a separate high-speed network but a single storage device attached to a LAN. SAS is statistical analysis software, and WAN is wide area network.

Answer 75

129. A, D. A network terminal access point (TAP) connects to a network in an area of concern and creates a copy of traffic, sending it on to monitoring devices. It can be an integral part of network management. TAPs can be active or passive. Passive TAPs do not require power or management, but active TAPs do.

Answer 76

132. B. Wireless Internet service providers (WISPs) that are operating in the 2.4 GHz band are limited to 4 watts of effective isotropic radiated power (EIRP) for their point-to-multipoint connections. Their point-to-point connections vary between 4 watts and 158 watts for the 2.4 GHz band. The maximum EIRP for the 5 GHz bands is 125 mw. FCC maximums can be found at www.air802.com/fcc-rules-and-regulations.html.

Answer 77

133. A. Channels 36 to 48 are set aside for domestic use. All channels above that require a router to have DFS and TPC. DFS will automatically switch to a different channel when weather radar and radar system signals are detected. TPC can be used to force clients to lower power so that they won’t interfere with nearby users or access points on the same channel. Channel 165 is set aside for industrial, scientific, and medical (ISM) use. In the United States, the FCC and IEEE are the authorities that approve channel uses.

Answer 78

134. B. The FCC’s ruling was expanded to include long-range fixed wireless hub or relay antennas and the customer’s right to place antennas of certain sizes on their premises, putting WISP providers on a more equal footing with satellite and cellular providers.

Answer 79

135. D. When an IP address and subnet mask are converted to the binary numbers that the computer sees, wherever there is a 1 in the subnet mask, that tells the computer that the corresponding bit in the IP address is part of the network number. Wherever there is a 0 in the subnet mask, the corresponding bit in the IP address is part of the host number. The address in the question, 192.168.2.200/24, is a Class C private address, where, in the subnet mask, the first three octets (24 bits) are all 1s, and the last octet (8 bits) are 0s. So, the first three decimal numbers of the IP address, which is expressed in dotted decimal notation, are the network number, (192.168.2) and the last octet (.200) is the host (individual computer) address. Network numbers will always go from left to right with no breaks between.

Answer 80

137. C. Load balancers do as their name implies. Rather than allow all incoming traffic on a port to go to one server or device, the traffic is distributed among devices. Proxy servers monitor incoming and outgoing packets, filtering them out based on specified criteria. Spam gateways don’t allow spam in; rather they are used to filter it out. Unified threat management (UTM) can employ an appliance or be software-driven, or even an outside service that monitors and manages malicious activities against a network.

Answer 81

138. A. Supervisory Control and Data Acquisition (SCADA) systems consist of both hardware and software. Hardware is used to gather information, which is sent to a computer running software that analyzes the data and logs events. SCADA can also initiate alarms when specified conditions exist. Infrared Data Association (IrDA) is network communications via infrared light. Unified threat management (UTM) is an appliance, software, or service that combines all malware security in one place. Remote Authentication Dial-In User Service (RADIUS) is a protocol for authentication servers that encrypts transmissions between client and server.

Answer 82

139. C. A DHCP server will “lease” an IP address to a client for a specified period of time. The default is usually 24 hours. In a SOHO where there are few new users, the lease time could be longer, but in a restaurant where many people come and go each hour, the DHCP scope might not have enough addresses to accommodate that many users. Setting the lease time to a shorter duration will release the IP address and make it available for a new user. MAC address filtering only allows connection from computers with specific MAC addresses and would greatly limit connectivity. Port forwarding sends traffic for a specific port to a specified computer on the network. The SSID is the wireless network name and can be broadcast so that it is easily found, or it can be hidden.

Answer 83

140. B. The Domain Name System (DNS) uses two types of records to resolve domain names to IP addresses. Type A records resolve the domain name to IPv4 addresses. Type AAAA records resolve domain names to IPv6 addresses. MAC and Physical addresses are two names for the NIC address.

Answer 84

141. A. Multiple Mail Exchanger (MX) records can be set up for a domain that specify different mail servers for load balancing. Direct Connect (DX) is an Amazon Web Services dedicated connection between client and AWS. AAAA signifies an IPv6 address in a DNS record, and TXT DNS records let an administrator specify text in their DNS record. These text records can be used to prevent email spam.

Answer 85

142. B. Sender Policy Framework (SPF) is a technique to prevent email address spoofing. It is done using a TXT entry in a domain’s DNS service. DomainKeys Identified Mail (DKIM) performs a similar function, but it uses a digital signature. Domain-Based Message Authentication, Reporting, and Conformance (DMARC) uses SPF or DKIM and in addition requires that the sender’s domain be the same as the DNS domain name. Domain administrators can specify to quarantine or reject emails that fail DMARC. To use DMARC, a DMARC record must exist in the DNS.

Answer 86

143. C. This is an IPv6 address. It is 128 bits long, and the last 64 bits are the interface ID, which identifies the individual computer. Since there are eight groups of hex numbers, that means the rightmost four groups are the interface ID. Any leading zeros in an IPv6 address can be omitted, and the :: can be used once in an address to replace consecutive groups of all zeros, so the number in the question fully expanded would be 2001:0000:0000:0000:01a3:0f1a:0308:0833. The interface ID is therefore 1a3:f1a:308:833. The leftmost three sections identify the network, and the fourth identifies the subnet. In this example, 2001:0:0 is the site prefix and 0 is the subnet ID. IPv6 addresses do not need a subnet mask like IPv4 addresses do

Answer 87

144. A, D. For decades now, wireless Internet service providers (WISPs) have been established by groups of individuals or small companies to provide Internet access to areas where it is not profitable for large commercial Internet providers to run, such as very rural areas. They are also called long-range fixed wireless providers. The first one was established in 1992 in the Midwest of the United States. Now there are thousands of them all over the world. In some areas of the world, where there is little or no wired infrastructure, WISPs are the only way that people can get Internet connectivity. A WISP connects to the Internet using either leased lines or microwaves, generally uses point-to-point microwaves between its towers, and uses point-to-multipoint connections between the final tower and users. An ISP is an Internet service provider, and a demarcation point is the place in a customer’s premises where the responsibility for the network changes from the ISP to the customer.

Answer 88

145. A, B. Option A is true. Channels 1, 6, and 11 are the only ones that don’t overlap in a 2.4 GHz network. Option B is also true. Each channel in a 2.4 GHz network is only about 5 MHz wide, while in a 5 GHz network the minimum is 20 MHz, but it can be configured to use 40 MHz or 80 MHz by combining channels. Option C is false. The 2.4 GHz frequency supports older devices; the 5 GHz frequency is newer. While 2.4 GHz channels overlap with the exception of 1, 6, and 11, 5 GHz channels don’t overlap. Your friend needs to choose a frequency and channel that are compatible with their devices, but the router may automatically configure the channel if using the 5 GHz frequency.

Answer 89

146. C. The Institute of Electrical and Electronics Engineers (IEEE) 802.11ax standard is now known as Wi-Fi 6, and is considered a replacement for 802.11ac (Wi-Fi 5). 802.11n is designated as Wi-Fi 4. Prior IEEE standards (802.11b, 802.11a, and 802.11g) are not designated with official Wi-Fi X nomenclature, but working backward in time, 802.11g would be Wi-Fi 3, 802.11a would be Wi-Fi 2, and 802.11b would be Wi-Fi 1. The CompTIA A+ objectives only ask that you know what Wi-Fi 5 and Wi-Fi 6 are.

2.0 Networking - A+ 1101 Flashcards

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