CompTIA®

Network+®

Study GuideFourth Edition

CompTIA®

Network+®

Study Guide Exam N10-007

Fourth Edition

Todd Lammle

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10 9 8 7 6 5 4 3 2 1

AcknowledgmentsKim Wimpsett was the development editor of this Sybex CompTIA series. Thank you, Kim, for your patience and kindness, and working so hard on this book with me.

Kenyon Brown was acquisitions editor for this book. Thank you, Kenyon, for making this book a reality!

In addition, Christine O’Connor was an excellent production editor, and she worked really hard to get the book done as quickly as possible, without missing the small mistakes that are so easy to overlook. I am always very pleased when I hear that she will be working with me on a new project.

Wynn D. Smith reviewed each topic in this guide, scrutinizing the material until we both agreed it was verifiably solid. Thank you, Wynn!

Troy McMillan literally hashed and rehashed each topic in this guide with me at all hours of the day and night. Thank you, Troy, yet again!

About the AuthorTodd Lammle, CompTIA Network+, CCSI, CCNA/CCNP, is the authority on network certification and internetworking. He is a world-renowned author, speaker, trainer, and consultant with more than 100 study guides in print. Todd has more than 30 years of experience working with LANs, WANs, and large licensed and unlicensed wireless networks and currently is working on a Cisco Security expert certification. He’s president and CEO of Todd Lammle, LLC, a network-integration and training firm based in Colorado, Texas, and San Francisco, California. You can reach Todd through his website at www.lammle.com/network±.

Contents at a GlanceIntroduction xxx

Assessment Test lxvi

Chapter 1 Introduction to Networks 1

Chapter 2 The Open Systems Interconnection Specifications 27

Chapter 3 Networking Topologies, Connectors, and Wiring Standards 55

Chapter 4 The Current Ethernet Specifications 91

Chapter 5 Networking Devices 125

Chapter 6 Introduction to the Internet Protocol 175

Chapter 7 IP Addressing 209

Chapter 8 IP Subnetting, Troubleshooting IP, and Introduction to NAT 237

Chapter 9 Introduction to IP Routing 279

Chapter 10 Routing Protocols 301

Chapter 11 Switching and Virtual LANs 341

Chapter 12 Wireless Networking 387

Chapter 13 Authentication and Access Control 439

Chapter 14 Network Threats and Mitigation 483

Chapter 15 Physical Security and Risk 543

Chapter 16 Wide Area Networks 593

Chapter 17 Troubleshooting Tools 635

Chapter 18 Software and Hardware Tools 691

Chapter 19 Network Troubleshooting 731

Chapter 20 Management, Monitoring, and Optimization 781

Appendix A Answers to Written Labs 841

Appendix B Answers to Review Questions 855

Appendix C Subnetting Class A 887

Index 895

ContentsIntroduction xxx

Assessment Test lxvi

Chapter 1 Introduction to Networks 1

First Things First: What’s a Network? 2The Local Area Network 3Common Network Components 5Wide Area Network 7Network Architecture: Peer-to-Peer or Client-Server? 9

Physical Network Topologies 11Bus Topology 12Star Topology 13Ring Topology 14Mesh Topology 15Point-to-Point Topology 16Point-to-Multipoint Topology 17Hybrid Topology 18

Topology Selection, Backbones, and Segments 19Selecting the Right Topology 19The Network Backbone 20Network Segments 21CAN 21SAN 21

Summary 21Exam Essentials 22Written Lab 22Review Questions 23

Chapter 2 The Open Systems Interconnection Specifications 27

Internetworking Models 28The Layered Approach 29Advantages of Reference Models 29

The OSI Reference Model 30The Application Layer 32The Presentation Layer 33The Session Layer 33The Transport Layer 33The Network Layer 40

xiv Contents

The Data Link Layer 42The Physical Layer 45

Introduction to Encapsulation 45Modulation Techniques 46Summary 47Exam Essentials 48Written Lab 48Review Questions 50

Chapter 3 Networking Topologies, Connectors, and Wiring Standards 55

Physical Media 57Coaxial Cable 58Twisted-Pair Cable 60Fiber-Optic Cable 64Transceivers 69Media Converters 69Serial Cables 71

Cable Properties 73Transmission Speeds 73Distance 74Duplex 74Noise Immunity (Security, EMI) 74Frequency 75

Wiring Standards 75T568A vs. T568B 75Straight-Through Cable 77Crossover Cable 78Rolled/Rollover Cable 80T1 Crossover Cable 80

Installing Wiring Distributions 82MDF/IDF 82

Summary 84Exam Essentials 85Written Lab 85Review Questions 87

Chapter 4 The Current Ethernet Specifications 91

Network Basics 92Ethernet Basics 94

Collision Domain 94Broadcast Domain 94CSMA/CD 95Broadband/Baseband 96

Contents xv

Bit Rates vs. Baud Rate 97Wavelength 97Half- and Full-Duplex Ethernet 98

Ethernet at the Data Link Layer 99Binary to Decimal and Hexadecimal Conversion 100Ethernet Addressing 103Ethernet Frames 104

Ethernet at the Physical Layer 106Ethernet over Other Standards (IEEE 1905.1-2013) 111

Ethernet over Power Line 112Ethernet over HDMI 113

Summary 114Exam Essentials 115Written Lab 115Review Questions 120

Chapter 5 Networking Devices 125

Common Network Connectivity Devices 128Network Interface Card 129Hub 130Bridge 131Switch 131Router 132Firewall 136IDS/IPS 137HIDS 137Access Point 138Wireless Range Extender 138Contention Methods 139Dynamic Host Configuration Protocol Server 141IPAM 146

Other Specialized Devices 146Multilayer Switch 147Load Balancer 147Domain Name Service Server 148Proxy Server 154Encryption Devices 155Analog Modem 156Packet Shaper 157VPN Concentrator 157Media Converter 158VoIP PBX 158VoIP Endpoint 158NGFW/Layer 7 Firewall 159VoIP Gateway 159

xvi Contents

Planning and Implementing a Basic SOHO Network Using Network Segmentation 159

Determining Requirements 159Switches and Bridges at the Data Link Layer 166Hubs at the Physical Layer 167Environmental Considerations 168

Summary 169Exam Essentials 169Written Lab 170Review Questions 171

Chapter 6 Introduction to the Internet Protocol 175

Introducing TCP/IP 177A Brief History of TCP/IP 177TCP/IP and the DoD Model 178The Process/Application Layer Protocols 180The Host-to-Host Layer Protocols 188The Internet Layer Protocols 192

Data Encapsulation 198Summary 202Exam Essentials 202Written Lab 203Review Questions 204

Chapter 7 IP Addressing 209

IP Terminology 210The Hierarchical IP Addressing Scheme 211

Network Addressing 212Private IP Addresses (RFC 1918) 216

IPv4 Address Types 218Layer 2 Broadcasts 219Layer 3 Broadcasts 219Unicast Address 219Multicast Address (Class D) 219

Internet Protocol Version 6 (IPv6) 220Why Do We Need IPv6? 220The Benefits of and Uses for IPv6 221IPv6 Addressing and Expressions 222Shortened Expression 223Address Types 224Special Addresses 225Stateless Autoconfiguration (EUI-64) 226DHCPv6 (Stateful) 227Migrating to IPv6 227

Contents xvii

Summary 230Exam Essentials 230Written Labs 231

Written Lab 7.1 231Written Lab 7.2 232Written Lab 7.3 232

Review Questions 233

Chapter 8 IP Subnetting, Troubleshooting IP, and Introduction to NAT 237

Subnetting Basics 238How to Create Subnets 239Subnet Masks 240Classless Inter-Domain Routing (CIDR) 241Subnetting Class C Addresses 243Subnetting Class B Addresses 253

Troubleshooting IP Addressing 260Determining IP Address Problems 263

Introduction to Network Address Translation (NAT) 268Types of Network Address Translation 269NAT Names 269How NAT Works 270

Summary 272Exam Essentials 272Written Lab 273Review Questions 274

Chapter 9 Introduction to IP Routing 279

Routing Basics 280The IP Routing Process 283Testing Your IP Routing Understanding 289Static and Dynamic Routing 291Summary 294Exam Essentials 294Written Lab 294Review Questions 296

Chapter 10 Routing Protocols 301

Routing Protocol Basics 302Administrative Distances 303Classes of Routing Protocols 305

Distance Vector Routing Protocols 306Routing Information Protocol (RIP) 308RIP Version 2 (RIPv2) 308

xviii Contents

VLSM and Discontiguous Networks 309EIGRP 312Border Gateway Protocol (BGP) 314

Link State Routing Protocols 315Open Shortest Path First (OSPF) 316Intermediate System-to-Intermediate System (IS-IS) 318

High Availability 319Hot Standby Router Protocol (HSRP) 321Virtual Router Redundancy Protocol 325

Advanced IPv6 Concepts 326Router Advertisement 326Neighbor Discovery 328Tunneling 329Dual Stack 332

IPv6 Routing Protocols 332RIPng 333EIGRPv6 333OSPFv3 333

Summary 334Exam Essentials 334Written Lab 335Review Questions 336

Chapter 11 Switching and Virtual LANs 341

Networking Before Layer 2 Switching 343Switching Services 346

Limitations of Layer 2 Switching 347Bridging vs. LAN Switching 348Three Switch Functions at Layer 2 348Distributed Switching 354

Spanning Tree Protocol 354Spanning Tree Port States 355STP Convergence 356Rapid Spanning Tree Protocol 802.1w 357

Virtual LANs 358VLAN Basics 359Quality of Service 362VLAN Memberships 363Static VLANs 363Dynamic VLANs 364Identifying VLANs 364VLAN Identification Methods 366

Contents xix

VLAN Trunking Protocol 367VTP Modes of Operation 368Do We Really Need to Put an IP Address on a Switch? 369Switch Port Protection 372Port Bonding 375Device Hardening 376

Two Additional Advanced Features of Switches 376Power over Ethernet (802.3af, 802.3at) 376Port Mirroring/Spanning (SPAN/RSPAN) 379

Summary 380Exam Essentials 381Written Lab 381Review Questions 383

Chapter 12 Wireless Networking 387

Introduction to Wireless Technology 390Cellular 393The 802.11 Standards 393

2.4 GHz (802.11b) 3952.4 GHz (802.11g) 3965 GHz (802.11a) 3975 GHz (802.11h) 3972.4 GHz/5 GHz (802.11n) 3985 GHz (802.11ac) 399

Comparing 802.11 Standards 399Range Comparisons 400

Wireless Network Components 401Wireless Access Points 401Wireless Network Interface Card 402Wireless Antennas 403

Installing a Wireless Network 405Ad Hoc Mode: Independent Basic Service Set 405Infrastructure Mode: Basic Service Set 406Wireless Controllers 407Mobile Hot Spots 409Signal Degradation 410Other Network Infrastructure Implementations 410Technologies that facilitate the Internet of Things (IoT) 412Installing and Configuring WLAN Hardware 412

Site Survey 418Providing Capacity 418Multiple Floors 420Location-Based WLAN 421Site Survey Tools 421

xx Contents

Wireless Security 422Wireless Threats 422Open Access 426Service Set Identifiers, Wired Equivalent Privacy,

and Media Access Control Address Authentication 426Remote Authentication Dial-In User Service (802.1X) 427Temporal Key Integrity Protocol 428Wi-Fi Protected Access or WPA2 Pre-Shared Key 430

Summary 433Exam Essentials 433Written Lab 434Review Questions 435

Chapter 13 Authentication and Access Control 439

Security Filtering 441Access Control Lists 442Tunneling 443Encryption 451Remote Access 455

Managing User Account and Password Security 458Managing User Accounts 459Managing Passwords 461Single Sign-On 465Local Authentication 466LDAP 466Certificates 466Multifactor Authentication 467

User-Authentication Methods 468Public Key Infrastructure (PKI) 468Kerberos 469Authentication, Authorization, and Accounting (AAA) 470Web Services 472Unified Voice Services 472Network Controllers 472Network Access Control (NAC) 472Challenge Handshake Authentication Protocol (CHAP) 473MS-CHAP 474Extensible Authentication Protocol (EAP) 474Hashes 474Network Access Control 475

Summary 476Exam Essentials 477Written Lab 477Review Questions 479

Contents xxi

Chapter 14 Network Threats and Mitigation 483

Recognizing Security Threats 485Denial of Service 486Distributed DoS (DDoS) 487Authentication Issues 495Viruses 496Zero-Day Attacks 499Insider Threat/Malicious Employee 500

Vulnerabilities 500Exploits vs. Vulnerabilities 500Unnecessary Running Services 500Open Ports 500Unpatched/Legacy Systems 501Unencrypted Channels 501TEMPEST/RF Emanation 501Malicious Users 501Buffer Overflow 503DNS Poisoning 503Wireless Threats 503Attackers and Their Tools 506Misconfiguration Issues 510Social Engineering (Phishing) 511

Understanding Mitigation Techniques 512Active Detection 513Passive Detection 513Proactive Defense 513Basic Forensic Concepts 514

Policies and Procedures 516Security Policies 517Security Training 524Patches and Upgrades 525Firmware Updates 527Driver Updates 527File Hashing 528Generating New Keys 528Upgrading vs. Downgrading 528Asset Disposal 530Detection 531

Anti-malware Software 532Host Based 533Cloud/Server Based 533Configuration Backups 534Updating Antivirus Components 534Fixing an Infected Computer 536

xxii Contents

Summary 537Exam Essentials 537Written Lab 537Review Questions 539

Chapter 15 Physical Security and Risk 543

Using Hardware and Software Security Devices 545Defining Firewalls 547

Network-Based Firewalls 548Host-Based Firewalls 548

Firewall Technologies 548Access Control Lists 549Port Security 551Demilitarized Zone 552Protocol Switching 553Dynamic Packet Filtering 555Proxy Services 556

Firewalls at the Application Layer vs. the Network Layer 558Stateful vs. Stateless Network Layer Firewalls 559NGFW/Layer7 Firewall 560

Scanning Services and Other Firewall Features 561Content Filtering 562Signature Identification 563Context Awareness 563Virtual Wire vs. Routed 563Zones 564

Intrusion Detection and Prevention Systems 566Network-Based IDS 567Host-Based IDS 569Vulnerability Scanners 570

VPN Concentrators 571Understanding Problems Affecting Device Security 572

Physical Security 572Logical Security Configurations 577Risk-Related Concepts 579

Summary 586Exam Essentials 587Written Lab 588Review Questions 589

Chapter 16 Wide Area Networks 593

What’s a WAN? 596Defining WAN Terms 596The Public Switched Telephone Network 598

Contents xxiii

WAN Connection Types 599Bandwidth or Speed 600

T-Series Connections 601The T1 Connection 602The T3 Connection 603

Transmission Media 603Wired Connections 603Wavelength Division Multiplexing 604Passive Optical Network 605Wireless Technologies 605

Broadband Services 607DSL Technology and xDSL 608Cable Modem 610

Wireless WAN Technologies 611Cellular WAN 612

WAN Protocols 613Integrated Services Digital Network 613Frame Relay Technology 615Point-to-Point Protocol 618DMVPN 621SIP Trunks 621Asynchronous Transfer Mode 622MPLS 623

WAN Troubleshooting 623Loss of Internet Connectivity 624Interface Errors/Monitoring 624Split Horizon 627DNS Issues 628Router Configurations 628Company Security Policy 629

Summary 629Exam Essentials 630Written Lab 631Review Questions 632

Chapter 17 Troubleshooting Tools 635

Protocol Analyzers 637Throughput Testers 638Connectivity Software 639Using traceroute 640

Using ipconfig and ifconfig 642Using the ifconfig Utility 646Using the iptables utility 646

xxiv Contents

Using the ping Utility 647Using the Address Resolution Protocol 650

The Windows ARP Table 651Using the arp Utility 651

Using the nslookup Utility 654Resolving Names with the Hosts Table 656Using the Mtr Command (pathping) 657

Using the Nmap Utility 658Using the route Command 659

Using the route Command Options 661Some Examples of the route Command 662

Using the nbtstat Utility 663The –a Switch 663The –A Switch 665The –c Switch 665The –n Switch 666The –r Switch 666The –R Switch 667The –S Switch 668The –s Switch 668

Using the netstat Utility 669The –a Switch 671The –e Switch 672The –r Switch 673The –s Switch 673The –p Switch 673The –n Switch 675

Using tcpdump 676Examples of Using tcpdump 676

Using the File Transfer Protocol 677Starting FTP and Logging In to an FTP Server 678Downloading Files 679Uploading Files 681

Using the Telnet Utility 682How to Enable Telnet in Windows 682Don’t Use Telnet, Use Secure Shell 683

Summary 684Exam Essentials 684Written Lab 685Review Questions 686

Contents xxv

Chapter 18 Software and Hardware Tools 691

Understanding Network Scanners 693Packet Sniffers/Network Monitors 693Intrusion Detection and Prevention Software 695Port Scanners 697Wi-Fi Analyzer 700Bandwidth Speed Tester 701

Baseline 702Network Monitoring and Logging 703

Network Monitoring 703SNMP 704Syslog 705SIEM 707Utilization 710

Identifying Hardware Tools 712Cable Testers 712Protocol Analyzer 715Certifiers 716Time-Domain Reflectometer 717Optical Time-Domain Reflectometer 717Multimeter 718Spectrum Analyzer 719Toner Generator (Probe) 720Metrics 721Butt Set 721Punch-Down Tool 722Cable Stripper/Snips 723Voltage Event Recorder (Power) 723Environmental Monitors 724

Summary 725Exam Essentials 725Written Lab 726Review Questions 727

Chapter 19 Network Troubleshooting 731

Narrowing Down the Problem 734Did You Check the Super Simple Stuff? 735Is Hardware or Software Causing the Problem? 738Is It a Workstation or a Server Problem? 739Which Segments of the Network Are Affected? 740Is It Bad Cabling? 740

xxvi Contents

Troubleshooting Steps 749Step 1: Identify the Problem 750Step 2: Establish a Theory of Probable Cause 754Step 3: Test the Theory to Determine Cause 762Step 4: Establish a Plan of Action to Resolve the

Problem and Identify Potential Effects 764Step 5: Implement the Solution or Escalate as Necessary 766Step 6: Verify Full System Functionality, and If

Applicable, Implement Preventative Measures 769Step 7: Document Findings, Actions, and Outcomes 769

Troubleshooting Tips 770Don’t Overlook the Small Stuff 770Prioritize Your Problems 771Check the Software Configuration 771Don’t Overlook Physical Conditions 772Don’t Overlook Cable Problems 772Check for Viruses 773

Summary 773Exam Essentials 774Written Lab 774Review Questions 776

Chapter 20 Management, Monitoring, and Optimization 781

Managing Network Documentation 785Using SNMP 785Schematics and Diagrams 786

Network Monitoring 795Baselines 795Processes 796On-Boarding and Off-Boarding of Mobile Devices 796NAC 796Policies, Procedures, and Regulations 797Safety Practices 801Implementing Network Segmentation 805

Network Optimization 808Reasons to Optimize Your Network’s Performance 808How to Optimize Performance 811Unified Communications 813Traffic Shaping 813Load Balancing 814High Availability 814Caching Engines 815Fault Tolerance 815

Contents xxvii

Archives/Backups 815Common Address Redundancy Protocol 816Virtual Networking 817Locating and Installing Equipment 825Change Management Procedures 832

Summary 834Exam Essentials 835Written Lab 836Review Questions 837

Appendix A Answers to Written Labs 841

Chapter 1: Introduction to Networks 842Chapter 2: The Open Systems Interconnection Specifications 842Chapter 3: Networking Topologies, Connectors,

and Wiring Standards 843Chapter 4: The Current Ethernet Specifications 843Chapter 5: Networking Devices 845Chapter 6: Introduction to the Internet Protocol 846Chapter 7: IP Addressing 847

Written Lab 7.1 847Written Lab 7.2 847Written Lab 7.3 848

Chapter 8: IP Subnetting, Troubleshooting IP, and Introduction to NAT  848

Chapter 9: Introduction to IP Routing 849Chapter 10: Routing Protocols 849Chapter 11: Switching and Virtual LANs 850Chapter 12: Wireless Networking 850Chapter 13: Authentication and Access Control 850Chapter 14: Network Threats and Mitigation 851Chapter 15: Physical Security and Risk 851Chapter 16: Wide Area Networks 852Chapter 17: Troubleshooting Tools 852Chapter 18: Software and Hardware Tools 853Chapter 19: Network Troubleshooting 853Chapter 20: Management, Monitoring, and Optimization  854

Appendix B Answers to Review Questions 855

Chapter 1: Introduction to Networks 856Chapter 2: The Open Systems Interconnection Specifications 857Chapter 3: Networking Topologies, Connectors, and

Wiring Standards 859Chapter 4: The Current Ethernet Specifications 860

xxviii Contents

Chapter 5: Networking Devices 861Chapter 6: Introduction to the Internet Protocol 863Chapter 7: IP Addressing 864Chapter 8: IP Subnetting, Troubleshooting IP, and

Introduction to NAT 866Chapter 9: Introduction to IP Routing 868Chapter 10: Routing Protocols 869Chapter 11: Switching and Virtual LANs 871Chapter 12: Wireless Networking 872Chapter 13: Authentication and Access Control 874Chapter 14: Network Threats and Mitigation 875Chapter 15: Physical Security and Risk 877Chapter 16: Wide Area Networks 878Chapter 17: Troubleshooting Tools 880Chapter 18: Software and Hardware Tools 881Chapter 19: Network Troubleshooting 883Chapter 20: Management, Monitoring, and Optimization 885

Appendix C Subnetting Class A 887

Subnetting Practice Examples: Class A Addresses 888Practice Example #1A: 255.255.0.0 (/16) 888Practice Example #2A: 255.255.240.0 (/20) 889Practice Example #3A: 255.255.255.192 (/26) 889

Subnetting in Your Head: Class A Addresses 890Written Lab 1 891Written Lab 2 892Answers to Written Lab 1 892Answers to Written Lab 2 893

Index 895