CompTIA Network+ Certification Guide: The ultimate guide to passing the N10-007 exam

CompTIA Network+ Certification Guide

The ultimate guide to passing the N10-007 exam

Glen D. Singh

Rishi Latchmepersad

BIRMINGHAM - MUMBAI

CompTIA Network+ Certification Guide

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Contributors

About the authors

Glen D. Singh is a cyber-security instructor, consultant, entrepreneur and public speaker. He has been conducting multiple training exercises in offensive security, digital forensics, network security, enterprise networking and IT service management annually. He also holds various information security certifications, such as the EC-Council's Certified Ethical Hacker (CEH), Computer Hacking Forensic Investigator (CHFI), Cisco's CCNA Security, CCNA Routing and Switching, and many others in the field of network security. Glen has been recognized for his passion and expertise by both the private and public sector organizations of Trinidad and Tobago and internationally.

I would like to thank my parents for their unconditional support and motivation they've always given me to become a better person each day. Thanks to my family, friends, and students for their continued support, the people at Packt Publishing for providing this amazing opportunity, and everyone who reads and supports this amazing book.

Rishi Latchmepersad is a Tier II data center engineer in the IP team at Air Link Networks, a medium-sized, Miami-based ISP that provides a number of video, co-location, and dedicated internet access facilities for numerous customers in the western-hemisphere. Rishi works alongside his team to manage the core IP network, managing infrastructure in a multi-vendor environment across several geographically diverse sites. Before taking on this role, Rishi worked at the University of the West Indies to develop a small network management solution (NMS) to measure several KPIs across a network by employing small probes in the network.

About the reviewer

Rishalin Pillay with over 11 years of cybersecurity experience has acquired a vast number of skills consulting for Fortune 500 companies while participating in projects involving the performance of tasks associated with network security design, implementation, and vulnerability analysis. 

He holds many certifications that demonstrate his knowledge and expertise in the cybersecurity field, including CISSP, CCNP Security, CCSPA, MCSE, MCT, A+, and Network+.

Rishalin currently works at a large software company as a senior cybersecurity engineer.

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Table of Contents

Title Page

Copyright and Credits

CompTIA Network+ Certification Guide

About Packt

Why subscribe?

Packt.com

Contributors

About the authors

About the reviewer

Packt is searching for authors like you

Preface

Who this book is for

What this book covers

To get the most out of this book

Download the color images

Conventions used

Get in touch

Reviews

The OSI Reference Model and the TCP/IP Stack

The OSI reference model

Relationship between the Protocol Data Unit (PDU) and Service Data Unit (SDU)

The seven layers of the OSI model

Application Layer

Presentation Layer

Session Layer

Transport Layer

Network Layer

Data Link Layer

Physical Layer

Communication using the relay system

The TCP/IP protocol suite

The four layers of the TCP/IP protocol suite

Communication using the TCP/IP protocol suite

Summary

Questions

Network Ports, Protocols, and Topologies

Technical requirements

Network port numbers

Network protocols

Protocol types

ICMP

ICMP message types

ICMP Type 0 – Echo Reply

ICMP Type 3 – Destination Unreachable

ICMP Type 5 – Redirect

ICMP Type 8 – Echo Request

ICMP Type 11 – Time Exceeded

TCP

User Datagram Protocol (UDP)

Comparison of TCP and UDP

IP

Protocols and ports

File Transfer Protocol (FTP)

Secure Shell (SSH), Secure Copy (SCP), and Secure FTP (SFTP)

Telnet

Simple Mail Transfer Protocol (SMTP)

Domain Name System (DNS)

Dynamic Host Configuration Protocol (DHCP)

Trivial File Transfer Protocol (TFTP)

Hypertext Transfer Protocol (HTTP)

Post Office Protocol (POP)

Network Time Protocol (NTP)

Internet Message Access Protocol (IMAP)

Simple Network Management Protocol (SNMP)

Lightweight Directory Access Protocol (LDAP)

HTTP Secure (HTTPS)

Server Message Block (SMB)

Remote Desktop Protocol (RDP)

Network topologies

Star

Ring

Bus

Hub and spoke

Mesh

Hybrid

Tree

Types of networks

Introducing Ethernet and its evolution

Summary

Questions

Further reading

Ethernet

What is Ethernet?

The sublayers of Ethernet

The Data Link Layer

The LLC sublayer

The MAC sublayer

Fields in an Ethernet frame

MAC addresses

Transmission types at the Data Link Layer

The CAM table

Summary

Questions

Understanding IPv4 and IPv6

IPv4 concepts

Converting binary into decimal

Converting decimal into binary

The format of an IPv4 packet

Public IPv4 addresses

Private IPv4 addresses

Subnet mask

Determining the Network ID

The laws of ANDing

Special IPv4 addresses

Loopback addresses

Link-local

TestNet

IPv4 transmission types

Subnetting

Step 1 – determining an appropriate class of address and why

Step 2 – creating subnets (subnetworks)

Step 3 – assigning each network an appropriate subnet and calculating the ranges

Step 4 – VLSM and subnetting a subnet

IP version 6 concepts

The format of an IPv6 packet

IPv6 coexistence on a network

IPv6 address representation

Prefix length

Types of IPv6 addresses

IPv6 transmission types

Configuring an IP address on a Windows system

Configuring an IP address on a Linux system

Configuring an IP address on a Cisco IOS router

Summary

Questions

Further reading

Routing and Switching Concepts

Properties of network traffic

Collision domain

Broadcast domain

Contention-based communication

Carrier Sense Multiple Access/Collision Detection (CSMA/CD)

Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA)

Maximum Transmission Unit (MTU)

Network segmentation

Virtual Local Area Network (VLAN)

Types of VLANs

Trunks

Port mirroring

Spanning Tree Protocol (STP)

Port roles

Routing protocols

Routing types

Static routing

Dynamic routing

Default route

Distance-vector routing protocols

Routing Information Protocol (RIP)

Enhanced Interior Gateway Routing Protocol (EIGRP)

Link-state routing protocols

Open Shortest Path First (OSPF)

Path vector routing protocol

Border Gateway Protocol (BGP)

Network Address Translation (NAT)

Static NAT

Dynamic NAT

PAT

Summary

Questions

Wireless and Cloud Technologies

Wireless technologies

Z-Wave

ANT+

Bluetooth

IEEE 802.15

Near Field Communication (NFC)

Infrared

Radio-Frequency Identification (RFID)

IEEE 802.16

802.11 wireless standards

802.11a

802.11b

802.11g

802.11n

802.11ac

802.11 comparison table

Frequencies

2.4 GHz

5 GHz

Cellular technologies

GSM

TDMA

CDMA

4G and LTE

Antenna and power requirements

Site surveys

Types of wireless LAN topologies

Wireless router configurations

Cloud computing

Types of cloud services

Software as a Service (SaaS)

Platform as a Service (PaaS)

 Infrastructure as a Service (IaaS)

Cloud delivery models

Private

Public

Hybrid

Community

Summary

Questions

Further reading

Network Components

Networking cables and connector types

Copper cables

Unshielded Twisted Pair (UTP) copper cables

Shielded Twisted Pair (STP) copper cables

Coaxial copper cables

Copper cable and termination standards

Fiber cables

Single-mode fiber (SMF) cables

MMF cables

Plenum-rated cables

Connector types

Copper cable connector types

Registered Jack (RJ)-45

RJ-11

Bayonet Neill-Concelman (BNC)

F-type

DB-9 and DB-25

Fiber cable connector types

Little Connector (LC)

Straight Tip (ST)

Subscriber Connector (SC)

Mechanical Transfer Registered Jack (MT-RJ)

Angled Physical Connector (APC) versus Ultra Polished Connector (UPC)

Transceivers

Gigabit Interface Converter (GBIC)

Small Form-Factor Pluggable (SFP), Enhanced Small Form-Factor Pluggable (SFP+), and Quad Small Form-Factor Pluggable (QSFP)

Duplex and bidirectional transceivers

Termination points

66 and 110 blocks

Patch panels

Copper termination standards

TIA/EIA 568A versus TIA/EIA 568B

Crossover versus straight-through

Networking devices and their deployment

Layer 1 devices

Hubs

Modulators/Demodulators (Modems)

Media converters

Wireless Access Points (WAPs) and Wireless Repeaters

Layer 2 devices

Bridges and switches

Layer 3 and higher devices

Routers

Security appliances

Voice over Internet Protocol (VoIP) devices

Servers

Summary

Questions

Further reading

Network Virtualization and WAN Technologies

Virtualization with networking concepts

Hypervisors

Type 1 hypervisor

Type 2 hypervisor

Virtual networking components

Virtual Switch (vSwitch)

Virtual firewall

Virtual routers

Storage technologies

NAS

SAN

Connection type

FC

Fibre Channel over Ethernet (FCoE)

Fibre Channel over IP (FCIP)

Jumbo Frame

WAN technologies

WAN topologies

P2P

Hub and spoke

Full mesh

Dual-homed

WAN service types

Integrated Services Digital Network (ISDN)

Leased lines

T1/T3

E1/E3

Digital Subscriber Line (DSL)

Metropolitan Ethernet

Cable broadband

Dial-up

MPLS

ATM

Frame Relay

Point-to-Point Protocol (PPP)

Point-to-Point Protocol over Ethernet (PPPoE)

Dynamic Multipoint VPN (DMVPN)

Transmission mediums

Satellite

Wireless

Copper cable

Fiber optic

WAN termination

Summary

Questions

Further reading

Business Continuity and Disaster Recovery Concepts

The role of documentation and diagrams

General documentation and diagramming concepts

Physical infrastructure documentation

Operational documentation

Business continuity and disaster recovery

Designing high-availability networks

Redundancy in power delivery

Recovery processes

Availability metrics

Common operational processes

Scanning and patching processes

Continuous monitoring

Summary

Questions

Further reading

Network Identity Management and Policies

Remote access methodologies

VPN

IPsec

Confidentiality

Encryption

Symmetric algorithm

Asymmetric algorithm

Integrity

Authentication

Anti-replay

Diffie-Hellman

IPsec protocols

Authentication Header (AH)

Encapsulation Security Payload (ESP)

SSL

Transport Layer Security (TLS)

VPN topologies

Site-to-site VPN

Remote access VPN

Remote Desktop Protocol (RDP)

Secure Shell (SSH)

Telnet

HTTPS

Identity policies and best practices

AUP

BYOD policy

Internet access policy

Password policy

Remote access policy

User account policy

Wireless network policy

Summary

Questions

Network Security Concepts

Wireless security

Wireless encryption standards

Wired Equivalent Privacy (WEP)

Wi-Fi Protected Access (WPA)

Wi-Fi Protected Access 2 (WPA2)

Authentication and security on a wireless network

Extensible Authentication Protocol (EAP)

EAP Flexible Authentication via Secure Tunneling (EAP-FAST)

EAP Transport Layer Security (EAP-TLS)

EAP Tunneled Transport Layer Security (EAP-TTLS)

Protected Extensible Authentication Protocol (PEAP)

MAC filtering

Geofencing

Network attacks and threats

Denial-of-Service (DoS)

Reflective

Amplified

Distributed

Social engineering

Insider threat

Logic bomb

Rogue Access Point (AP)

Evil twin

War-driving

Ransomware

DNS poisoning

ARP poisoning

Deauthentication

Brute force

Virtual Local Area Network (VLAN) hopping

Exploits versus vulnerabilities

Securing networking devices

 Changing default credentials

Microsoft Windows

Linux

Other devices

Avoiding common passwords

Device hardening

Disabling unnecessary services

Disabling services in Windows

Linux

Cisco

Network scanning

Disabling physical ports

Mitigation techniques

Network segmentation – Demilitarized Zone (DMZ)

Network segmentation – VLANs

Changing the native VLAN

Spanning Tree Protocol (STP) threat mitigation techniques

Bridge Protocol Data Unit (BPDU) guard

Root guard

DHCP snooping

Honeypot and honeynet

Penetration testing

Summary

Questions

Further reading

TCP/IP Security

Vulnerabilities at the Application Layer

Cross Site Scripting (XSS)

SQL injection (SQLi)

Lightweight Directory Access Protocol (LDAP) injection

Cross-Site Request Forgery (CSRF)

Session hijacking

Cookie poisoning

DNS

Distributed Denial-of-Service (DDoS)

Registrar hijacking

Cache poisoning

Typosquatting

Vulnerabilities at the Transport Layer

Fingerprinting

Enumeration

DNS enumeration

DNS zone transfer

Microsoft RPC Endpoint Mapper

SMTP

SYN flooding

TCP reassembly and sequencing

Vulnerabilities at the Internet Layer

Route spoofing

IP address spoofing

Internet Control Message Protocol (ICMP)

DoS vulnerability in ICMP

Smurf attack

Teardrop attack

Ping of Death (PoD)

Vulnerabilities at the Network Access/Link Layer

Data Link Layer

Address Resolution Protocol (ARP) poisoning

Sniffing

Broadcast storms

VLAN hopping

Physical Layer

Wiretapping

Other physical issues

Securing TCP/IP using a DiD approach

Mitigating security threats

Implement a next-generation firewall

Implement an IPS

Implement Web Security Appliance (WSA)

Implementing Email Security Appliance

Implement layer 2 security on switches

Implement Virtual Private Networks (VPNs)

Other important security checks

Summary

Questions

Organizational Security

Physical security

Video surveillance

Asset-tracking tags

Tamper detection

Prevention techniques

Badges

Biometrics

Security tokens

Locks

Authentication concepts

Remote Authentication Dial-In User Service (RADIUS)

Terminal Access Controller Access Control System (TACACS)

Kerberos

Multi-Factor Authentication (MFA)

Summary

Questions

Troubleshooting a Network

Proper network troubleshooting methodology

Utilizing appropriate troubleshooting tools

Hardware-based troubleshooting tools

Software-based troubleshooting tools

Common issues on wired networks

Common issues on wireless networks

Common network service issues

Summary

Questions

Further reading

Assessment

Chapter 1: The OSI Reference Model and the TCP/IP Stack

Chapter 2: Network Ports, Protocols, and Topologies

Chapter 3: Ethernet

Chapter 4: Understanding IPv4 and IPv6

Chapter 5: Routing and Switching Concepts

Chapter 6: Wireless and Cloud Technologies

Chapter 7: Network Components

Chapter 8: Network Virtualization and WAN Technologies

Chapter 9: Business Continuity and Disaster Recovery Concepts

Chapter 10: Network Identity Management and Policies

Chapter 11: Network Security Concepts

Chapter 12: TCP/IP Security

Chapter 13: Organizational Security

Chapter 14: Troubleshooting a Network

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Preface

CompTIA-certified professionals have always held the upper hand in the IT industry. This book will be your ideal guide to passing and achieving this certification efficiently, learning from industry experts and implementing their practices in order to resolve complex IT issues.

This book will focus on networking concepts; readers will learn everything from network architecture to security, network monitoring, and troubleshooting. This book will not only prepare readers conceptually, but will also help them to pass the N10-007 exam.

This guide will also provide practical exercises at the end of every chapter, where readers can ensure that they understand the concepts fully.

By the end of this book, readers will leverage this guide and the included practice questions to boost their confidence in appearing for the actual certificate.

Who this book is for

This book is intended for readers wanting to pass the CompTIA Network+ certificate. Rookie network engineers and system administrators interested in enhancing their networking skills would also benefit from this book. No prior knowledge of networking is required.

What this book covers

Chapter 1, The OSI Reference Model and the TCP/IP Stack, covers both the OSI reference model and TCP/IP stack, and the purpose of network port numbers, protocols, and network design (topologies). Furthermore, the reader will be introduced to IP addressing and subnetting, the fundamentals of routing and switching concepts, and cloud technologies.

Chapter 2, Network Ports, Protocols, and Topologies, discusses the importance of network ports on a system and the different protocols that are used in networks. The reader will also learn about network design using diagrams that are known as network topologies.

Chapter 3, Ethernet, explains the fundamentals of Ethernet and its importance on a network. This chapter also covers the sub-layers of Ethernet and how each sub-layer interacts with other components and protocols on the network.

Chapter 4, Understanding IPv4 and IPv6, delves into the different classes of IP addressing and their assignments. The second half of this chapter will teach the reader how to break down an IP address block into smaller subnetworks for better efficiency.

Chapter 5, Routing and Switching Concepts, covers the properties of network traffic, segmentation, network performance concepts, how traffic is routed between networks, and how switching works.

Chapter 6, Wireless and Cloud Technologies, explains the fundamentals of wireless technologies and configurations. The second half of this chapter will discuss cloud technologies and their uses.

Chapter 7, Network Components, describes the different types of wired media and their connectors and determines the appropriate placement of networking devices on a network.

Chapter 8, Network Virtualization and WAN Technologies, helps the reader to understand how virtualization technologies can be used in a network infrastructure and its benefits, while exploring network storage technologies and wide-area network technologies and concepts.

Chapter 9, Business Continuity and Disaster Recovery Concepts, focuses on network uptime and ensuring a high availability of network resources. It provides an insight into business continuity and disaster recovery concepts, ensuring that proper network documentation and topology diagrams are available and secured. Concluding this chapter, the reader will be able to use appropriate tools to scan and monitor a network to prevent and mitigate security risks.

Chapter 10, Network Identity Management and Policies, discusses how access works on a network and introduces methods for ensuring that it is secure for users and organizations. We will then dive into discussing identity management, policies, and best practices.

Chapter 11, Network Security Concepts, focuses primarily on understanding the different types of cybersecurity threats and network attacks, securing a wireless and wired network infrastructure using best practices and mitigation techniques.

Chapter 12, TCP/IP Security, focuses on the vulnerabilities in the TCP/IP design and how an attacker can take advantage of weaknesses in the layers of the TCP/IP stack to leverage an attack and exploit these vulnerabilities further. The reader will learn how to adopt best practices and apply security to the TCP/IP stack.

Chapter 13, Organizational Security, covers a number of aspects of organizational security, providing the reader with information on physical security concepts, such as the purpose of physical devices and access control methods and concepts. This is important when it comes to helping to restrict unauthorized access to the physical network infrastructure and its components.

Chapter 14, Troubleshooting a Network, teaches the reader how to troubleshoot using a systematic approach involving a variety of methods, using the appropriate network security tools to identify and mitigate various network security threats, and troubleshooting both a wired and wireless network infrastructure and network services.

To get the most out of this book

In this book, we need the following:

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Wireless router

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781789340501_ColorImages.pdf.

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: Using the show ip arp command on a Cisco IOS device, we can once again see the current ARP entries.

A block of code is set as follows:

0 AND 1 = 0

0 AND 0 = 0

1 AND 0 = 0

1 AND 1 = 1

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

[default]

exten => s,1,Dial(Zap/1|30)

exten => s,2,Voicemail(u100)

exten => s,102,Voicemail(b100)

exten => i,1,Voicemail(s0)

Any command-line input or output is written as follows:

$ mkdir css

$ cd css

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: Select System info from the Administration panel.

Warnings or important notes appear like this.

Tips and tricks appear like this.

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The OSI Reference Model and the TCP/IP Stack

The Internet—the largest computer network in the world today, is constructed from several protocols and protocol suites that work together to allow users (like you and I) to communicate across the globe. A protocol is simply a rule, or a collection of rules and conventions, that a device (such as your computer) follows in order to communicate with other devices around the world (which follow those same rules). A protocol suite is simply a collection of these rules, which work together to allow complex applications on networking devices (for example, web browsers on your computer) to communicate with billions of other devices around the world, through an assortment of networking equipment and media:

In this chapter, we will discuss two protocol suites in particular that have largely influenced the internet as we know it today:

The Open Systems Interconnection (OSI) reference model

The Transmission Control Protocol/Internet Protocol (TCP/IP) suite

Although these two protocol suites possess significant differences between them, they both serve as important blocks in the foundation of the internet, and, as such, they both continue to exist as important concepts that budding Network Engineers and System Administrators must understand and appreciate if they wish to become exceptional in their careers.

By understanding these two protocol suites, professionals add an important tool to their arsenal of network troubleshooting weaponry; namely, a systematic, step-by-step approach to be followed in the diagnostic processing of any networking issue, which both simplifies and speeds up the process of pinpointing the root cause of an issue and the rectification of the situation. These suites allow both equipment vendors and Network Engineers to segment the operation of a network into several discrete modular parts or layers, and deal with each layer individually. This allows us to focus on a single part of a system at a time, thus greatly simplifying the development and troubleshooting of networking equipment.

To illustrate this concept in a real-life scenario, consider the following situation—you're a System Administrator in a small IT firm. It's 4 o'clock on a Friday evening and you're excited to clock out and start your weekend. Suddenly, your Syslog Server starts sending emails to all the administrators in your team, complaining about a reachability issue regarding a particular server in your datacenter. Your co-workers immediately begin to panic, knowing that several employees have already left and that they'll likely be working late on a Friday evening. However, since you've mastered your protocol suites, you immediately locate the server and begin troubleshooting the issue from the Physical Layer upwards, quickly locating a disconnected cable to the server and saving your team a lot of troubleshooting time and stress:

For the rest of this chapter, we will first discuss the OSI reference model, delving into a bit of its history and the combination of factors and entities that led to its development and subsequent publication in 1984, before discussing each of the seven layers of the developed model in detail, explaining the purpose of each of the layers and illustrating how each of the layers interact to effect communication between devices across a network. We will then introduce the TCP/IP protocol suite, comparing and contrasting it to the OSI reference model, and similarly explaining and illustrating how each of the layers plays a vital role in transmitting messages across a network. Lastly, we will conclude this chapter with a set of practice questions, which will allow you to test how much information you've retained about the content we've covered in this chapter.

The OSI reference model

Development of the OSI reference model began in the late 1970s in response to the amalgam of proprietary, non-interoperable networking equipment and protocols that vendors were creating at that time. Networks had to be built entirely out of equipment from a single vendor, since networks built from equipment from different vendors could not easily be interconnected. The OSI reference model was thus designed as one solution to this interoperability problem. The development of this model was fueled by two teams—one from the International Organization for Standardization (ISO), and the other from the Consultative Committee for International Telephony and Telegraphy (CCITT). The aim of the model was to become a global framework for protocol development, allowing a diverse array of networking and computing architecture to easily interconnect and communicate.

The standard describing the model, titled ISO/IEC 7498-1, was initially published in 1984, with a second edition succeeding it in 1994.

You can download and view the actual ISO standard at https://standards.iso.org/ittf/PubliclyAvailableStandards/s020269_ISO_IEC_7498-1_1994(E).zip.

The OSI reference model described by the standard consists of seven layers:

The Application Layer (layer 7)

The Presentation Layer (layer 6)

The Session Layer (layer 5)

The Transport Layer (layer 4)

The Network Layer (layer 3)

The Data Link Layer (layer