Networking

Which TCP/IP protocol is responsible for dynamically assigning IP addresses to client computers? A. DNS B. DHCP C. RDP D. LDAP

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.

Which one of the following TCP/IP protocols was designed as a replacement for Telnet? 1. SMB 2. SSH 3. SFTP 4. FTPS

B. Secure Shell (SSH) can be used to set up a secure session over port 22 for remote logins or for remotely executing programs and transferring files. Because it's secure, it was originally designed to be a replacement for the unsecure telnet command. Server Message Block (SMB), File Transfer Protocol (FTP), and FTP Secure (FTPS) protocols are used for sharing files across a network.

Which of the following IP addresses is not a private address and therefore is routable on the Internet? 10.1.2.3 172.18.31.54 172.168.38.155 192.168.38.155

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.

Which type of IPv6 address identifies a single node on the network? A. Multicast B. Anycast C. Unicast D. Localcast

C. There are three types of addresses in IPv6: unicast, anycast, and multicast. A unicast address identifies a single node on the network. An anycast address refers to one that has been assigned to multiple nodes, and a packet will be delivered to one of them. A multicast address is one that identifies multiple hosts, and a packet will be sent to all of them.

If you are connecting to a website that encrypts its connection using TLS, what port does that traffic travel on? 21 80 143 443

D. To encrypt traffic between a web server and client securely, Hypertext Transfer Protocol Secure (HTTPS) can be used. HTTPS connections are secured using either Secure Sockets Layer (SSL) or Transport Layer Security (TLS). HTTPS uses port 443. Port 21 is used by File Transfer Protocol (FTP), port 80 is used by Hypertext Transfer Protocol (HTTP), and port 143 is used by Internet Mail Access Protocol (IMAP).

Which of the following are public IPv4 addresses? (Choose two.) A. 69.252.80.71 B. 144.160.155.40 C. 172.20.10.11 D. 169.254.1.100

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.

Which of the following IPv6 addresses is equivalent to 127.0.0.1 in IPv4? A. ::0 B. ::1 C. ::127 D. 2000::/3

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

Which TCP/IP protocol is used to provide shared access to files and printers on the network? 1. FTP 2. SSH 3. SMB 4. SMTP

C. Server Message Block (SMB) is a protocol used to provide shared access to files, printers, and other network resources. In a way, it functions a bit like File Transfer Protocol (FTP), only with a few more options, such as the ability to connect to printers and more management commands. Secure Shell (SSH) uses encryption to create a secure contact between two computers, and Simple Mail Transfer Protocol (SMTP) is used for sending email.

You are installing a fiber-optic cable between two buildings. To install the cable, you must run it through a conduit between the buildings, and access to the conduit is not easy. Before you run the cable, you want to ensure that it's working properly. Which tool should you use? 1. Cable tester 2. Multimeter 3. Loopback plug 4. Tone generator and probe

A. Cable testers are indispensable tools for any network technician. Usually you would use a cable tester before you install a cable to make sure it works. Of course, you can test them after they've been run as well. Multimeters are used to test power supplies and wall outlets. Loopback plugs are used to test network interface cards, and tone generators and probes are used to locate a wire among other wires.

You have just installed a wireless 802.11ac network for a client. The IT manager is concerned about competitors intercepting the wireless signal from outside the building. Which tool is designed to test how far your wireless signal travels? 1. Tone generator and probe 2. Protocol analyzer 3. Packet sniffer 4. Wi-Fi analyzer

D. A wireless locator, or a Wi-Fi analyzer, can be either a handheld hardware device or specialized software that is installed on a laptop, smartphone, or other mobile device and whose purpose is to detect and analyze Wi-Fi signals. It can detect where signals are strong or weak to determine whether there are potential security issues. A tone generator and probe are used for locating a wire. Protocol analyzers and packet sniffers are tools used for capturing and analyzing network traffic.

What type of network spans multiple buildings or offices, possibly even crossing roads, but is confined to a relatively small geographical area? LAN WAN PAN MAN

D. Networks that are larger than a LAN but confined to a relatively small geographical area are metropolitan area networks (MANs). A MAN is generally defined as a network that spans a city or a large campus. LAN stands for local area network. PAN (personal area network) is the smallest of the types of networks, and a WAN is the largest type of network. It could connect faraway cities or even other countries.

You are configuring hosts on a network running IPv4. Which elements are required for the computer to connect to the network? IP address IP address and subnet mask IP address, subnet mask, and default gateway IP address, subnet mask, default gateway, and DNS server address

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.

You are troubleshooting a computer with an IPv6 address that is in the FE80::/10 range. Which of the following statements are true? (Choose two.) A. The computer will not be able to get on the Internet using that IP address. B. The computer will be able to get on the Internet using that IP address. C. The computer is configured with a link-local unicast address. D. The computer is configured with a global unicast address.

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.

Which of the following devices will be found in a telecommunications room and provides a means to congregate horizontal wiring, terminating each run in a female port? A. Patch panel B. Multiplexer C. Rack U D. Demarcation point

A. A patch panel can be found in a telecommunications room (also called a wiring closet), usually mounted in a networking rack. On the back will be connections to "punch down" wires into. On the front will be a female port, usually an RJ45 type. A multiplexer is a device that aggregates several connections into one. A rack U is simply a measurement of the height of a device mounted into a rack (e.g., my patch panel is 4U). Each U is equal to 1.75 inches. The demarcation point is where responsibility for a network changes from the ISP to its customer.

Which of the following shorthand notations corresponds to the CIDR subnet mask 255.255.224.0? /19 /20 /21 /22

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).

What rendition of SMB was used by Windows servers and NAS servers but is no longer often used? A. CIFS B. Samba C. NFS D. SMB3

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.

You are configuring a wireless 802.11ax router. The office manager insists that you configure the router such that traffic from her computer receives higher priority on the network than other users' traffic. Which setting do you need to configure to enable this? QoS UPnP Screened subnet Port forwarding

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.

Which TCP/IP protocol, developed by Microsoft, uses port 3389 to connect to a remote computer? A. RDP B. SMB C. CIFS D. Telnet

A. Developed by Microsoft, the Remote Desktop Protocol (RDP) allows users to connect to remote computers and run programs on them as if they were sitting at the computer. It uses port 3389. A port is associated with a specific protocol and must be "opened" on a router to allow traffic from the program or protocol to enter the LAN. The combination of an IP address and a port is considered a socket. The IP address gets the data to the right destination, and the port number tells the transmission layer of the OSI model which application the data is to be sent to. Server Message Block (SMB) and Common Internet File System (CIFS) are used in sharing files across a network. Telnet is an unsecure protocol that has been largely replaced by the Secure Shell (SSH) protocol.

You are installing network cabling in a highly secure facility. The cables need to be immune to electronic eavesdropping. What type of cable should you use? A. Fiber-optic B. UTP C. STP D. Coaxial

A. Fiber-optic cabling uses pulses of light instead of electric voltages to transmit data, so it is immune to electrical interference and to wiretapping. UTP, STP, and coaxial are all copper cables, which use electricity to transmit data and so can be subjected to electronic eavesdropping.

Bob has a device that operates at 5 GHz. He is unable to connect his device to a LAN that he hasn't accessed before, although he has verified that he has the correct password. What type of network might pose this problem? 1. 802.11g 2. 802.11n 3. 802.11ac 4. 802.11ax

A. If Bob is trying to connect to an 802.11g network, his device will not be able to connect because 802.11g operates on the 2.4 GHz frequency only. 802.11n and 802.11ax both operate on 2.4 GHz and 5 GHz. 802.11ac operates only on the 5 GHz frequency.

Which of the following IP addresses is not routable on the Internet? A. 10.1.1.1 B. 11.1.1.1 C. 12.1.1.1 D. 13.1.1.1

A. Private IP addresses are not routable on the Internet. IPv4 network numbers were arranged in classes, and classes A, B, and C each have their own private range. The private IP address range for Class A networks is 10.0.0.0/8. The /8 means that the first 8 bits of the subnet mask denote the network number. Expressing a subnet mask this way is known as CIDR (pronounced cider) notation. CIDR stands for classless interdomain routing. While the term CIDR doesn't appear on the objectives for this CompTIA A+ exam, you may still run into it while working in IT.

What type of address does a router use to get data to its destination? A. IP B. MAC C. Memory D. Loopback

A. Routers are OSI model Layer 3 devices. They keep a chart containing the IP address of the device connected to each port, whether that device is a computer or another router's external address. A media access control (MAC) address is the address of a network interface card (NIC). Memory addresses identify where information is stored, and a loopback address is used to test TCP/IP on the local host. The loopback address for IPv4 is 127.0.0.1, and for IPv6 it is ::1.

Which TCP/IP protocol gathers and manages network performance information using devices called agents? A. SNMP B. SMTP C. LDAP D. SMB

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.

You are using your laptop on the company network. In your web browser, you type www.google.com and press Enter. The computer will not find Google. You open the browser on your phone, and using your cellular connection, you can open Google without a problem. Your laptop finds internal servers and can print without any issues. What is the most likely reason you can't open Google? 1. DNS server problem 2. DHCP server problem 3. Missing subnet mask 4. Duplicate IP address

A. The Domain Name System (DNS) server is responsible for resolving hostnames, such as www.google.com, to IP addresses to enable communication. If it's not working properly or you can't connect to it, you won't be able to browse the Internet using friendly website names. Dynamic Host Configuration Protocol (DHCP) is used to assign IP addresses to network clients. The subnet mask might be incorrect, but it wouldn't be missing, and a duplicate IP address would provide an error message stating that.

You have set up your web server to function as an FTP server as well. Users on the Internet complain that they are not able to access the server using FTP clients. What port should they be trying to access the server on? A. 21 B. 22 C. 23 D. 80

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.

Which TCP/IP Internet layer protocol is responsible for delivering error messages if communication between two computers fails? A. ICMP B. IP C. TCP D. UDP

A. The main Internet layer protocol is Internet Protocol (IP), and it's the workhorse of TCP/IP. Another key protocol at this layer is Internet Control Message Protocol (ICMP), which is responsible for delivering error messages. If you're familiar with the ping utility, you'll know that it utilizes ICMP to send and receive packets. Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are both communication protocols; TCP guarantees delivery but UDP does not.

Which network connectivity device does not forward broadcast messages, thereby creating multiple broadcast domains? A. Hub B. Switch C. Bridge D. Router

Answer:D. One of the key features of routers is that they break up broadcast domains. Broadcast traffic from one port of the router will not get passed to the other ports, which greatly reduces network traffic. Bridges, hubs, and switches will all forward broadcast packets.

For IPv6, which of the following statements are true? (Choose two.) A. Each IPv6 interface can have only one address. B. Each IPv6 interface is required to have a link-local address. C. IPv6 addresses are incompatible with IPv4 networks. D. IPv6 does not use broadcasts.

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.

Which of the following network connectivity devices operates at Layer 2 of the OSI model? 1. Hub 2. Switch 3. Cable 4. Router

B. A switch operates at layer 2 of the open systems interconnection (OSI) model. Layers of the OSI model are (1) physical, (2) datalink, (3) network, (4) transport, (5) session, (6) presentation, and (7) application. The physical layer encompasses transmission media such as unshielded twisted pair (UTP), shielded twisted pair (STP), fiber optic, and so on. The datalink layer deals with transmitting frames on a LAN, so it includes the network interface card (NIC) and switch. Routers operate on OSI layer 3, because they transmit data between networks. Hubs work on OSI layer 1 because they merely connect devices in the same collision domain without regard to packet header information. The OSI model is not listed as an objective on the CompTIA A+ exam, but understanding it will help you understand network communications.

What type of network covers large geographical areas and often supports thousands of users, often using lines owned by other entities? A. LAN B. WAN C. PAN D. MAN

B. A wide area network (WAN) covers large geographical areas and often supports thousands of users. A WAN can be for different locations of a single company, or a WAN may connect several different companies together to share information. WAN lines are often leased from a WAN provider. The Internet is considered to be a very large WAN. A local area network (LAN) covers a relatively small area such as a home or business. A personal area network (PAN) is usually used by one person and consists of their computer and its Bluetooth devices. A metropolitan area network (MAN) is similar to a WAN, but the area covered is much smaller, such as a university or a city.

Which TCP/IP port will an email client use to push email to its email server? A. 23 B. 25 C. 110 D. 143

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.

Which network connectivity device is seldom used in modern networks, except to extend a network? A. Bridge B. Hub C. Switch D. Router

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.)

You need to install a wireless access point in a drop ceiling where there is no access to a power source. Which technology will allow you to get power to that device? EoP PoE Hub Repeater/extender

B. Power over Ethernet (PoE) allows you to power an Ethernet device (such as a switch) through one of the Ethernet ports. For it to work, the access point and the device it plugs into both need to support PoE. Further, both the access point and device need to be compatible with each other. EoP, while not on the current A+ objectives, is a technology that allows the user to transmit Ethernet signals over existing power lines. This can be useful in a place where running Ethernet wires is impossible, but more often Wi-Fi is used in those situations instead. A hub can be used to regenerate a signal, but they also need a power source and are not a wireless access point. A repeater/extender is essentially the same as a hub. It requires power to regenerate a signal and send it on its way.

Which of the following technologies will enable you to install networking devices that need power to function, in a location that has no power outlets? A. EoP B. PoE C. WAP D. Hub

B. Power over Ethernet (PoE) enables placement of equipment in areas that otherwise would not be able to accept it. Only four of the eight wires in twisted pair wiring are used for communication. The power is sent over the wires that are not used in communication. If the devices on both ends don't support PoE, then an injector can be used to add power to the line on the way to its destination. Compatibility is important, and there are limits to the amount of power that can be transmitted this way. Ethernet over Power (EoP) is not in the CompTIA A+ objectives, but it uses special devices to send Ethernet communications over existing wiring such as in a household. A wireless access point (WAP) is a device that is used to connect wireless devices to a wired network or to each other. Some WAPs support PoE. A hub is a very simple network connectivity device.

What port does the SSH protocol use? A. 21 B. 22 C. 23 D. 25

B. Secure Shell (SSH) can be used to set up a secure session for remote logins or for remotely executing programs and transferring files. SSH uses port 22. SSH has largely replaced the insecure Telnet, which uses port 23. Port 21 is used by File Transfer Protocol (FTP), and port 25 is used by Simple Mail Transfer Protocol (SMTP).

Which networking device has multiple ports, each of which is its own collision domain, and examines the header of the incoming packet to determine which port the packet gets sent to? A. Hub B. Switch C. Bridge D. Router

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.

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.

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.

You have been asked to install a Wi-Fi network in a building that is approximately 100 meters long and 25 meters wide. Because of cost considerations, you will be using 802.11ac. At a minimum, how many wireless access points will you need? A. Two B. Three C. Four D. Six

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.

There is a TCP/IP protocol that should only be used locally because it has virtually no security. It may be used as a part of a preboot execution environment (PXE) or with thin clients booting from a network drive. It uses very little memory and is good for transferring boot files or configuration data between computers on a LAN, and it is connectionless. Which file transfer protocol is this? A. FTP B. TFTP C. FTPS D. SMTP

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.

You are configuring network hosts with static IP addresses. You have chosen to use a Class B network address. What is the default subnet mask that you should configure on the hosts? A. 255.0.0.0 B. 255.255.0.0 C. 255.255.255.0 D. 255.255.255.255

B. The default subnet mask for Class B networks is 255.255.0.0, or written in shorthand, /16. The default subnet mask for Class A networks is 255.0.0.0, or written in shorthand, /8, and for Class C it is 255.255.255.0, or written in shorthand, /24. 255.255.255.255 is an IPv4 broadcast address. As a subnet mask it is represented as /32 (in shorthand) in the classless interdomain routing (CIDR) notation.

Which of the following TCP/IP protocols is connection-oriented and attempts to guarantee packet delivery? 1. IP 2. TCP 3. UDP 4. ICMP

B. Transmission Control Protocol (TCP) guarantees packet delivery through the use of a virtual circuit and data acknowledgments, and User Datagram Protocol (UDP) does not. Because of this, TCP is often referred to as connection-oriented, whereas UDP is connectionless. Internet Protocol (IP) is used to get packets to their destination across the Internet, and Internet Control Message Protocol (ICMP) is used by connectivity devices to diagnose problems and send messages.

What two tools will you need to connect an RJ45 connector to an appropriate cable? (Choose two.) Punchdown tool Network tap Crimper Cable stripper

C, D. Punchdown tools are used to connect unshielded twisted pair (UTP) and shielded twisted pair (STP) to a patch panel. A network tap is used to monitor network traffic. The crimper and cable stripper are both needed to add an RJ45 connector to the end of a twisted pair cable. Often both tools are included in one. The stripper removes the outer insulation from the group of wires so that they can be individually inserted into the RJ45 jack. Once the wires are properly inserted, the crimping tool is used to force metal teeth into each wire so that an electrical connection can be made.

You want to ensure that client computers can download email from external email servers regardless of the protocol their email client uses. Which ports do you open on the firewall to enable this? (Choose two.) A. 23 B. 25 C. 110 D. 143

C, D. Simple Mail Transfer Protocol (SMTP, port 25), Post Office Protocol 3 (POP3, port 110), and Internet Message Access Protocol (IMAP, port 143) are all email protocols. SMTP is for sending email. POP3 and IMAP are for downloading (receiving) email. Port 23 is used by Telnet. Option B is incorrect because the question specifically asks about downloading (not sending) email.

Which Wi-Fi standard is the fastest, operating in both the 2.4 and 5 GHz frequencies? 1. 802.11a 2. 802.11ac 3. 802.11ax 4. 802.11n

C. 802.11ax (Wi-Fi 6) is considered a replacement for 802.11ac (Wi-Fi 5). 802.11ac operates in the 5 GHz frequency, while 802.11ax can operate between 1 and 7.125 GHz frequencies, encompassing the 2.4 GHz and 5 GHz bands. 802.11ac can send data at over 1 Gbps, while 802.11ax can be several times that. 802.11a was adopted in 1999. It operates at 54 Mbps in the 5 GHz frequency band. 802.11n was adopted in 2008. It operates at 600 Mbps in both the 2.4 GHz and 5 GHz ranges.

Your network is currently running a mix of 802.11b and 802.11g devices. At the end of the year, you have extra budget to upgrade some, but not all, of the wireless infrastructure. You want to upgrade to the newest technology possible but still maintain backward compatibility. Which standard should you choose? 802.11g 802.11ac 802.11ax 802.11r

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.

You are troubleshooting an intermittently failing Cat 6 network connection. You suspect that there is a short in the connection. Which tool can you use to determine this? A. Tone generator and probe B. Loopback plug C. Cable tester D. Crimper

C. A cable tester typically uses lights to indicate that the cable is working correctly, and if there is a short, then the indicators for two wires would light up at the same time. Cable testers can range from basic ones that are only a few dollars to very sophisticated ones that are hundreds of dollars. Some of the better ones can tell you how many feet from you that the problem in the cable occurs. A tone generator and probe are used to trace a wire or find a specific wire from a group, a loopback plug is used to test a network interface card (NIC), and a crimper attaches a network wire to its terminator, usually an RJ45 plug.

Which network device is designed to be a security guard, blocking malicious data from entering your network? A. PoE injector B. EoP device C. Firewall D. Router

C. A firewall is a hardware or software solution that serves as your network's security guard. Firewalls can protect you in two ways: they protect your network resources from hackers lurking in the dark corners of the Internet, and they can simultaneously prevent computers on your network from accessing undesirable content on the Internet or sending out data that they shouldn't. PoE stands for Power over Ethernet, and EoP stands for Ethernet over Power. Neither has to do with protection. While a router may incorporate a firewall, it is not, by itself, a firewall. Routers are responsible for communications with other networks or broadcast domains. A firewall may be a discrete physical network appliance or software incorporated into another device like a router.

You have a desktop computer that is behaving erratically on the network. The wired connection will often disconnect without warning. Which tool should you use to troubleshoot the network adapter? A. Multimeter B. Tone generator and probe C. Loopback plug D. Cable tester

C. A loopback plug is for testing the ability of a network adapter to send and receive. The plug gets plugged into the network interface card (NIC), and then a loopback test is performed using troubleshooting software. You can then tell whether the card is working properly. Multimeters are used for testing power supplies and wall outlets, a tone generator and probe help the technician to find a specific wire, and a cable tester checks that an Ethernet wire was configured correctly and that it can make an end-to-end connection.

What type of network is most commonly associated with Bluetooth devices such as wireless keyboards, mice, and headphones, and covers a small area? A. LAN B. WAN C. PAN D. MAN

C. A personal area network (PAN) is a small-scale network designed around one person within a limited boundary area. The term generally refers to networks that use Bluetooth technology. A local area network (LAN) covers a larger area such as a house or perhaps one floor of a building and likely uses the Ethernet protocol. A metropolitan area network (MAN) covers a larger area such as a city or university campus, and a wide area network (WAN) covers a very large geographic area such as one connecting distant cities or different countries.

Which Internet connection type, once popular for home use, offers asymmetrical download and upload speeds and is implemented over common phone lines? A. POTS B. Cable C. DSL D. ISDN

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.

Which of the following IPv6 addresses is automatically assigned by the host when it boots and is only usable on the broadcast domain that it exists in? A. 2000::/3 B. FC00::/7 C. FE80::/10 D. FF00::/8

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.

Which of the following Internet connection types offers the fastest download speeds? A. Cable B. DSL C. Fiber-optic D. Satellite

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.

What marks the boundary of a IPv4 broadcast domain? A. Hub B. Switch C. Router D. Modem

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.

Which TCP/IP protocol, designed to download email, allows for multiple clients to be simultaneously connected to the same mailbox? 1. SMTP 2. POP3 3. IMAP 4. SMB

C. Internet Message Access Protocol (IMAP) is a secure protocol designed to download email. It has several advantages over the older Post Office Protocol 3 (POP3). First, IMAP4 works in connected and disconnected modes. Second, it lets you store the email on the server, as opposed to POP3, which requires you to download it. Third, IMAP4 allows multiple clients to be simultaneously connected to the same inbox. Simple Mail Transfer Protocol (SMTP) is used for sending mail, and Server Message Block (SMB) is used in sharing files across a network.

Some of your network users are concerned about submitting confidential information to an online website. What should you tell them? A. It's fine, because all Internet traffic is encrypted. B. If the website address starts with TLS://, it should be OK to submit confidential information to a trusted site. C. If the website address starts with HTTPS://, it should be OK to submit confidential information to a trusted site. D. Don't ever submit confidential information to any online website.

C. Internet traffic is not encrypted by default. Websites that are secure and encrypt their transmissions will start with HTTPS:// rather than HTTP://. These sites can be trusted to encrypt the data, and their identity is verified.

What port is associated with the LDAP protocol? A. 22 B. 139 C. 389 D. 3389

C. Lightweight Directory Access Protocol (LDAP) is designed to access information stored in an information directory typically known as an LDAP directory or LDAP database. LDAP uses port 389. Port 22 is used by Secure Shell (SSH,) 139 is used by NetBIOS, and 3389 is used by the Remote Desktop Protocol (RDP.)

A technician is going to set up a Wi-Fi network using standard omnidirectional antennae. Because of the building configuration, transmitting signals for the greatest distance is the technician's primary criterion. Which standard should they choose? A. 802.11a B. 802.11g C. 802.11n D. 802.11ac

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.

Which TCP/IP protocol uses port 445? A. FTP B. SSH C. SMB D. SNMP

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.

What port does the Telnet protocol use? 1. 21 2. 22 3. 23 4. 25

C. Telnet lets users log into another machine and "see" the remote computer in a window on their screen. Although this vision is text only, users can manage files on that remote machine just as if they were logged in locally. Telnet uses port 23. Telnet has been largely replaced by Secure Shell (SSH), and SSH (over port 22) is more secure than Telnet. Port 21 is used by File Transfer Protocol (FTP), and port 25 is used by Simple Mail Transfer Protocol (SMTP).

You are installing an 802.11n Wi-Fi network with five wireless access points. The access points are set up so their ranges overlap each other. To avoid communications issues, what principle should you follow when configuring them? A. Configure all access points to use the same channel. B. Configure all access points to use adjacent channels. C. Configure all access points to use nonoverlapping channels. D. Channel configuration will not cause communications issues.

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.

Your company just expanded and is leasing additional space in an adjacent office building. You need to extend the network to the new building. Fortunately, there is a conduit between the two. You estimate that the cable you need to run will be about 300 meters long. What type of cable should you use? A. CAT-5e B. CAT-7 C. CAT-8 D. MMF

D. Category 5, 6, and 7 UTP cables are limited to 100 meters, while Category 8 is limited to only 100 feet, so none of the UTP cables listed will work. You need fiber, and multimode fiber (MMF) can span distances of 300 meters. MMF is also known as OM1, OM2, OM3, OM4, and OM5. OM stands for optical mode. Specifications for each type of multimode fiber are available in the ISO/IEC 11801 standard.

You are asked to perform consulting work for a medium-sized company that is having network connectivity issues. When you examine the patch panel, you notice that none of the dozens of UTP cables are labeled. Which tool can you use to identify which cable goes to which workstation? A. Cable tester B. Loopback plug C. Punchdown tool D. Tone generator and probe

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.

You are installing a new network and working in a telecommunications room. You need to attach several network cables to a 110 block. Which tool should you use to perform this task? A. Crimper B. Cable stripper C. Cable tester D. Punchdown tool

D. If you're working on a larger network installation, you might use a punchdown tool. It's not a testing tool but one that allows you to connect (that is, punch down) the exposed ends of a twisted pair wire into wiring harnesses, such as a 110 block or patch panel. A crimper is used to connect wires to an RJ45 connector, a cable striper removes the outer cover from wires, and a cable tester is used to verify the integrity of a cable.

You need to configure email settings for use with IMAP. Which port will you be configuring? A. 25 B. 80 C. 110 D. 143

D. Internet Mail Access Protocol (IMAP) is used to download mail via port 143. Port 80 is for unsecured web page traffic. Ports 25 and 110 are email ports, but they are associated with SMTP and POP3, respectively.

Which TCP/IP protocol allows a user to log into a remote computer and manage files as if they were logged in locally? 1. FTP 2. SFTP 3. SMB 4. RDP

D. Remote Desktop Protocol (RDP) is a replacement for the older Telnet protocol, which is not secure. RDP, as its name implies, lets users log into a local machine and use a remote machine almost as if they were sitting at it. RDP uses port 3389. File Transfer Protocol (FTP), Secure File Transfer Protocol (SFTP), also called Secure Shell (SSH) FTP, and Server Message Block (SMB) protocols are all used for sharing files across a network.

Which networking device is capable of reading IP addresses and forwarding packets based on the destination IP address? A. Hub B. Switch C. NIC D. Router

D. Routers operate at the Network layer (Layer 3) of the OSI model. Because of this, they make their decisions on what to do with traffic based on logical addresses, such as an Internet Protocol (IP) address. Switches use media access control (MAC) addresses and are OSI Layer 2 devices. Hubs and NICs operate primarily at the physical layer (Layer 1). The OSI model is not listed as an objective on the CompTIA A+ exam, but understanding it will help you understand network communications.

Which TCP/IP protocol allows you to access data such as employee phone numbers and email addresses that are stored within an information directory? A. SNMP B. SMTP C. CIFS D. LDAP

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.

You are installing network cabling in a drop ceiling of an office space. The ceiling area is used to circulate breathable air. What type of cable must you install? Coaxial UTP Fiber-optic Plenum

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.

You are manually configuring TCP/IP hosts on the network. What configuration parameter specifies the internal address of the router that enables Internet access? A. Subnet mask B. DHCP server C. DNS server D. Default gateway

D. The default gateway is the address to the network's router on the LAN side of the router. The router allows the host to communicate with hosts who are not on the local network. The default gateway is also called the router's internal address. The ipconfig /all command can be used to see the default gateway address that the local computer is currently configured to use. The router will also have an external address, which is used to communicate with networks outside the LAN. Virtually all modern routers use a process called network address translation (NAT), which will substitute the router's external address for a host's IP address when requesting information from a remote network. The router knows which host requested the information and will pass it on to the correct host when it is received. This is one of the ways that the router protects the local hosts from the outside world.

You need to configure a wireless router for an office network. The office manager wants new devices to be able to automatically join the network and announce their presence to other networked devices. Which service should you enable to allow this? A. DHCP B. NAT C. QoS D. UPnP

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.