220-1101 Networking Study Guide for the CompTIA A+ Core Series Exam

Basic Wired/Wireless Small Office/Home Office (SOHO) Networks

When setting up a small office/home office (SOHO) network, keep the following steps in mind:

Understand relevant regulations.
Make a map.
Locate the server(s).
Identify client computer locations.
Locate network resources.
Determine user connectivity type.
Designate additional connectivity options if needed.

You must be able to install and configure basic wired and wireless SOHO networks. On the CompTIA A+ exam, these concepts will be addressed in scenario-based questions.

Internet Protocol (IP) Addressing

Internet protocol (IP) addressing is the assignment of a unique device identifier on a local network or the internet. The IP address is responsible for managing logical network addresses.

IPv4

An IPv4 address is a 32-bit hierarchical address that identifies a host on a network and is typically written in dotted-decimal notation. The 32-bit address is divided into 4 bytes, or octets, containing 8 bits each (ex: 192.168.10.55). IPv4 addresses are divided into designated classes, A, B, C, D, E, and F, based on the first 3 bits of the IP address. IPv4 addresses are finite and are running out.

Private addresses—A private IP address is not routable on the internet.

Class A private address range: 10.0.0.0–10.255.255.255
Class B private address range: 172.16.0.0–172.31.255.255
Class C private address range: 192.168.0.0.–192.168.255.255

Public addresses—Public addresses are routable on the internet. Public addresses are purchased and only one computer can hold any given public address at a time.

IPv6

IPv6 addresses are 128-bit addresses expressed in hexadecimal notation and are composed of eight 16-bit fields separated by colons (ex: 2001:0db8:3c4d:0012:0000:0000:1234:56ab, which can be reduced to 2001:db8:3c4d:12::1234:56ab)

Automatic Private IP Addressing (APIPA)

Automatic private IP addressing (APIPA) assigns an IP address to a device that was not assigned a static or dynamic IP address. The address will be in the 169.254.0.0 network. This is generally not useful, other than being an indication that the device failed to get an IP address through normal means. These addresses are also referred to as link-local addresses.

Static

A static address is one that is set manually by a user or administrator. A device that is assigned a static address will keep that address until someone changes the configuration.

Dynamic

A dynamic address is one that is automatically assigned, typically by a router or DHCP server. The next time a device that was dynamically assigned an IP address joins the network, it may be assigned a different IP address.

Gateway

A gateway is a router that connects your network to another network, typically the Internet. When configuring a device on the network, you specify the internal IP address of the gateway as a default destination to send traffic.

Common Network Configuration Concepts

You must be able to compare and contrast common network configuration concepts for the CompTIA A+ exam.

DNS

The domain name system (DNS) has only one function: to resolve hostnames to IP addresses. DNS settings are usually given out via DHCP along with IP address information, but this can be done manually as well. This allows the user (client) to resolve domain names to IP addresses in order to perform searches or lookups. These are usually given out in a primary and secondary fashion for redundancy purposes.

Address

Addresses are contained on the DNS server in zone files. The zone file maintains records of hostname-to-IP address mappings and contains information such as the name of the server or computer, internet protocol address, record type, computer address, and comments.

A—A is a common DNS record type that signifies that the host record is an IPv4 address.

AAAA—AAAA, pronounced “quad A”, is a common DNS record type that signifies the host record is an IPv6 address.

Mail Exchanger (MX)

A mail exchanger (MX) record is a common DNS record type that signifies that the host record is the name or address of an email server.

Text (TXT)

A text (TXT) record is a common DNS record type that signifies that the host record is a text record for human-readable or machine-readable data.

Spam Management

Spam management is the process of determining if data is spam or valid.

DKIM—DomainKeys Identified Mail (DKIM) is a type of spam management that authenticates using encryption through a public-private key pair.

SPF—Sender Policy Framework (SPF) is a type of spam management that authenticates an email server based on its IP address.

DMARC—Domain-based Message Authentication, Reporting and Conformance (DMARC) is a type of spam management that combines DKIM and SPF in one framework and offers more control over what the user can do with spam email.

DHCP

The Dynamic Host Configuration Protocol (DHCP) automatically assigns all of the settings needed to access resources on your LAN or the internet. It can provide IP address, subnet, gateway, and DNS information. If you want to ensure that a device gets a specific IP address, you can configure a DHCP reservation in the DHCP server.

Leases

A lease is a temporary IP configuration assigned by the DHCP server to a client. A lease typically includes an IP address, subnet mask, default gateway, and DNS server address.

Reservations

A reservation is the reserving of an IP address for a specific client based on the client’s MAC address and is primarily used for devices that require a static IP address.

Scope

The scope is information provided outside the IP address and the subnet mask issued by the DHCP server, such as the default gateway, DNS server address, or domain name.

Virtual LAN (VLAN)

A virtual local area network (VLAN) is a logical subnet, typically configured on a switch, that acts as a separate subnet. Without VLANs, every device connected to a switch would be on the same subnet. By configuring VLANs on the switch, you can have devices on that one switch in different subnets or VLANs.

Virtual Private Network (VPN)

A virtual private network (VPN) is an encrypted connection between two networks or between a host and a network. When a host connects to a network over a VPN, it is assigned a separate IP address that is in the network’s address range.

Internet Connection Types and Network Types

For this exam, you should understand the specific networks and internet connections listed below and understand the differences between them.

Internet Connection Types

Internet connection types are methods, either wired or wireless, through which a device can connect to the internet.

Satellite—A satellite connection is a wireless connection type that employs the use of satellites to achieve connectivity. Satellite connections are typically slower than wired broadband connections and require a satellite dish. Weather and misalignment can affect connectivity.

Fiber—A fiber connection is a type of wired connection that uses a fiber-optic cable made of thin flexible glass or plastic fiber surrounded by a rubberized outer sheath to send data via light signals. Fiber offers fast data transmission. There are two types of fiber varieties: single-mode fiber (SMF) and multimode fiber (MMF).

Cable—A cable connection is a type of wired connection that uses a cable, either coaxial/coax or twisted pair, for data transmission. Coax and twisted pair cables use different connector types and cable specifications.

DSL—A digital subscriber line (DSL) is a type of wired connection that uses existing phone lines paired with a DSL modem to provide internet service.

Cellular—A cellular connection is a type of wireless connection type that uses a provider’s cellular network for connectivity.

WISP—A wireless internet service provider (WISP) is a wireless connection type in which an internet service provider (ISP) offers connectivity using wireless technology. WISP connections are fixed point-to-point connections.

Network Types

Network types define the general area that is covered by a network.

LAN—A local area network (LAN) is a collection of devices connected to one another in one physical area, such as an office building, and can be small or large.

WAN—A wide area network (WAN) is a network that covers a large geographical area and is composed of multiple LANs. The internet is a WAN.

PAN—A personal area network (PAN) is composed of primarily Bluetooth-connected devices.

MAN—A metropolitan area network (MAN) is a network larger than a LAN but smaller than a WAN and limited to a smaller geographical area, such as a city or a campus.

SAN—A storage area network (SAN) is a network area composed of storage devices.

WLAN—A wireless local area network (WLAN) is a LAN in which the connections are wireless rather than wired.

Networking Tools

For the CompTIA A+ exam, you should be able to evaluate a set of network requirements in a given scenario and select the best network tool for the job.

Crimper

A crimper is used to connect a connector to a cable. It is not usually practical to use cables of a fixed length. It is also easier to run cable without the connectors on it. So, the cable is run and cut to the desired length, and then the connector is crimped on using a crimper. There are different types of crimpers for ethernet, coaxial, and fiber-optic cables.

Cable Stripper

Cable strippers are used to remove the insulation from the end of a cable before the connector is crimped onto it.

Wi-Fi Analyzer

A Wi-Fi analyzer is used to design, optimize, or troubleshoot a Wi-Fi network. This device is used to show strong and weak spots in wireless coverage. It is a way to visualize Wi-Fi network coverage.

Toner Probe

These devices are used to locate cables in a wiring closet. The tone generator is typically placed at the user end, and a probe is waved around in the wiring closet to locate the connection. It will make a distinctive noise when it is near the correct cable.

Punchdown Tool

A punchdown tool is used to connect the exposed ends of a wire into a wiring harness.

Cable Tester

This device is used to certify that the cable meets the standards of the wiring code and to ensure it can be used for communication. It will identify broken wires or missing pin connections.

Loopback Plug

A loopback plug is a special cable that is wired to transmit and receive on a single connector. There are loopback plugs for different types of connectors, like USB or ethernet, for testing network interface cards (NICs).

Network TAP

A network test access port (TAP) is a hardware device that creates a copy of network traffic for use by monitoring devices without interfering with network traffic. A network TAP can be easily moved from location to location to identify problems.