CompTIA Network+ Study Guide

Todd Lammle, Network+, CCSI, CCNA, CCNP, is the networking authority. He has been involved in computers and networking with Fortune 500 companies for almost 30 years. Todd is President of GlobalNet System Solutions, Inc., a networking integration and training firm. He is the bestselling author of numerous titles, with over 900,000 copies of his books in print. He can be reached through his website at www.lammle.com.

Introduction xxx

Assessment Test lxvi

Chapter 1 Introduction to Networks 1

First Things First: What’s a Network? 2

The Local Area Network 3

Common Network Components 5

Wide Area Network 7

Network Architecture: Peer-to-Peer or Client-Server? 9

Physical Network Topologies 11

Bus Topology 12

Star Topology 13

Ring Topology 14

Mesh Topology 15

Point-to-Point Topology 16

Point-to-Multipoint Topology 17

Hybrid Topology 18

Topology Selection, Backbones, and Segments 19

Selecting the Right Topology 19

The Network Backbone 20

Network Segments 21

CAN 21

SAN 21

Summary 21

Exam Essentials 22

Written Lab 22

Review Questions 23

Chapter 2 The Open Systems Interconnection Specifications 27

Internetworking Models 28

The Layered Approach 29

Advantages of Reference Models 29

The OSI Reference Model 30

The Application Layer 32

The Presentation Layer 33

The Session Layer 33

The Transport Layer 33

The Network Layer 40

The Data Link Layer 42

The Physical Layer 45

Introduction to Encapsulation 45

Modulation Techniques 46

Summary 47

Exam Essentials 48

Written Lab 48

Review Questions 50

Chapter 3 Networking Topologies, Connectors, and Wiring Standards 55

Physical Media 57

Coaxial Cable 58

Twisted-Pair Cable 60

Fiber-Optic Cable 64

Transceivers 69

Media Converters 69

Serial Cables 71

Cable Properties 73

Transmission Speeds 73

Distance 74

Duplex 74

Noise Immunity (Security, EMI) 74

Frequency 75

Wiring Standards 75

T568A vs. T568B 75

Straight-Through Cable 77

Crossover Cable 78

Rolled/Rollover Cable 80

T1 Crossover Cable 80

Installing Wiring Distributions 82

MDF/IDF 82

Summary 84

Exam Essentials 85

Written Lab 85

Review Questions 87

Chapter 4 The Current Ethernet Specifications 91

Network Basics 92

Ethernet Basics 94

Collision Domain 94

Broadcast Domain 94

CSMA/CD 95

Broadband/Baseband 96

Bit Rates vs. Baud Rate 97

Wavelength 97

Half- and Full-Duplex Ethernet 98

Ethernet at the Data Link Layer 99

Binary to Decimal and Hexadecimal Conversion 100

Ethernet Addressing 103

Ethernet Frames 104

Ethernet at the Physical Layer 106

Ethernet over Other Standards (IEEE 1905.1-2013) 111

Ethernet over Power Line 112

Ethernet over HDMI 113

Summary 114

Exam Essentials 115

Written Lab 115

Review Questions 120

Chapter 5 Networking Devices 125

Common Network Connectivity Devices 128

Network Interface Card 129

Hub 130

Bridge 131

Switch 131

Router 132

Firewall 136

IDS/IPS 137

HIDS 137

Access Point 138

Wireless Range Extender 138

Contention Methods 139

Dynamic Host Configuration Protocol Server 141

IPAM 146

Other Specialized Devices 146

Multilayer Switch 147

Load Balancer 147

Domain Name Service Server 148

Proxy Server 154

Encryption Devices 155

Analog Modem 156

Packet Shaper 157

VPN Concentrator 157

Media Converter 158

VoIP PBX 158

VoIP Endpoint 158

NGFW/Layer 7 Firewall 159

VoIP Gateway 159

Planning and Implementing a Basic SOHO Network Using Network Segmentation 159

Determining Requirements 159

Switches and Bridges at the Data Link Layer 166

Hubs at the Physical Layer 167

Environmental Considerations 168

Summary 169

Exam Essentials 169

Written Lab 170

Review Questions 171

Chapter 6 Introduction to the Internet Protocol 175

Introducing TCP/IP 177

A Brief History of TCP/IP 177

TCP/IP and the DoD Model 178

The Process/Application Layer Protocols 180

The Host-to-Host Layer Protocols 188

The Internet Layer Protocols 192

Data Encapsulation 198

Summary 202

Exam Essentials 202

Written Lab 203

Review Questions 204

Chapter 7 IP Addressing 209

IP Terminology 210

The Hierarchical IP Addressing Scheme 211

Network Addressing 212

Private IP Addresses (RFC 1918) 216

IPv4 Address Types 218

Layer 2 Broadcasts 219

Layer 3 Broadcasts 219

Unicast Address 219

Multicast Address (Class D) 219

Internet Protocol Version 6 (IPv6) 220

Why Do We Need IPv6? 220

The Benefits of and Uses for IPv6 221

IPv6 Addressing and Expressions 222

Shortened Expression 223

Address Types 224

Special Addresses 225

Stateless Autoconfiguration (EUI-64) 226

DHCPv6 (Stateful) 227

Migrating to IPv6 227

Summary 230

Exam Essentials 230

Written Labs 231

Written Lab 7.1 231

Written Lab 7.2 232

Written Lab 7.3 232

Review Questions 233

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

Subnetting Basics 238

How to Create Subnets 239

Subnet Masks 240

Classless Inter-Domain Routing (CIDR) 241

Subnetting Class C Addresses 243

Subnetting Class B Addresses 253

Troubleshooting IP Addressing 260

Determining IP Address Problems 263

Introduction to Network Address Translation (NAT) 268

Types of Network Address Translation 269

NAT Names 269

How NAT Works 270

Summary 272

Exam Essentials 272

Written Lab 273

Review Questions 274

Chapter 9 Introduction to IP Routing 279

Routing Basics 280

The IP Routing Process 283

Testing Your IP Routing Understanding 289

Static and Dynamic Routing 291

Summary 294

Exam Essentials 294

Written Lab 294

Review Questions 296

Chapter 10 Routing Protocols 301

Routing Protocol Basics 302

Administrative Distances 303

Classes of Routing Protocols 305

Distance Vector Routing Protocols 306

Routing Information Protocol (RIP) 308

RIP Version 2 (RIPv2) 308

VLSM and Discontiguous Networks 309

EIGRP 312

Border Gateway Protocol (BGP) 314

Link State Routing Protocols 315

Open Shortest Path First (OSPF) 316

Intermediate System-to-Intermediate System (IS-IS) 318

High Availability 319

Hot Standby Router Protocol (HSRP) 321

Virtual Router Redundancy Protocol 325

Advanced IPv6 Concepts 326

Router Advertisement 326

Neighbor Discovery 328

Tunneling 329

Dual Stack 332

IPv6 Routing Protocols 332

RIPng 333

EIGRPv6 333

OSPFv3 333

Summary 334

Exam Essentials 334

Written Lab 335

Review Questions 336

Chapter 11 Switching and Virtual LANs 341

Networking Before Layer 2 Switching 343

Switching Services 346

Limitations of Layer 2 Switching 347

Bridging vs. LAN Switching 348

Three Switch Functions at Layer 2 348

Distributed Switching 354

Spanning Tree Protocol 354

Spanning Tree Port States 355

STP Convergence 356

Rapid Spanning Tree Protocol 802.1w 357

Virtual LANs 358

VLAN Basics 359

Quality of Service 362

VLAN Memberships 363

Static VLANs 363

Dynamic VLANs 364

Identifying VLANs 364

VLAN Identification Methods 366

VLAN Trunking Protocol 367

VTP Modes of Operation 368

Do We Really Need to Put an IP Address on a Switch? 369

Switch Port Protection 372

Port Bonding 375

Device Hardening 376

Two Additional Advanced Features of Switches 376

Power over Ethernet (802.3af, 802.3at) 376

Port Mirroring/Spanning (SPAN/RSPAN) 379

Summary 380

Exam Essentials 381

Written Lab 381

Review Questions 383

Chapter 12 Wireless Networking 387

Introduction to Wireless Technology 390

Cellular 393

The 802.11 Standards 393

2.4 GHz (802.11b) 395

2.4 GHz (802.11g) 396

5 GHz (802.11a) 397

5 GHz (802.11h) 397

2.4 GHz/5 GHz (802.11n) 398

5 GHz (802.11ac) 399

Comparing 802.11 Standards 399

Range Comparisons 400

Wireless Network Components 401

Wireless Access Points 401

Wireless Network Interface Card 402

Wireless Antennas 403

Installing a Wireless Network 405

Ad Hoc Mode: Independent Basic Service Set 405

Infrastructure Mode: Basic Service Set 406

Wireless Controllers 407

Mobile Hot Spots 409

Signal Degradation 410

Other Network Infrastructure Implementations 410

Technologies that facilitate the Internet of Things (IoT) 412

Installing and Configuring WLAN Hardware 412

Site Survey 418

Providing Capacity 418

Multiple Floors 420

Location-Based WLAN 421

Site Survey Tools 421

Wireless Security 422

Wireless Threats 422

Open Access 426

Service Set Identifiers, Wired Equivalent Privacy, and Media Access Control Address Authentication 426

Remote Authentication Dial-In User Service (802.1X) 427

Temporal Key Integrity Protocol 428

Wi-Fi Protected Access or WPA2 Pre-Shared Key 430

Summary 433

Exam Essentials 433

Written Lab 434

Review Questions 435

Chapter 13 Authentication and Access Control 439

Security Filtering 441

Access Control Lists 442

Tunneling 443

Encryption 451

Remote Access 455

Managing User Account and Password Security 458

Managing User Accounts 459

Managing Passwords 461

Single Sign-On 465

Local Authentication 466

LDAP 466

Certificates 466

Multifactor Authentication 467

User-Authentication Methods 468

Public Key Infrastructure (PKI) 468

Kerberos 469

Authentication, Authorization, and Accounting (AAA) 470

Web Services 472

Unified Voice Services 472

Network Controllers 472

Network Access Control (NAC) 472

Challenge Handshake Authentication Protocol (CHAP) 473

MS-CHAP 474

Extensible Authentication Protocol (EAP) 474

Hashes 474

Network Access Control 475

Summary 476

Exam Essentials 477

Written Lab 477

Review Questions 479

Chapter 14 Network Threats and Mitigation 483

Recognizing Security Threats 485

Denial of Service 486

Distributed DoS (DDoS) 487

Authentication Issues 495

Viruses 496

Zero-Day Attacks 499

Insider Threat/Malicious Employee 500

Vulnerabilities 500

Exploits vs. Vulnerabilities 500

Unnecessary Running Services 500

Open Ports 500

Unpatched/Legacy Systems 501

Unencrypted Channels 501

TEMPEST/RF Emanation 501

Malicious Users 501

Buffer Overflow 503

DNS Poisoning 503

Wireless Threats 503

Attackers and Their Tools 506

Misconfiguration Issues 510

Social Engineering (Phishing) 511

Understanding Mitigation Techniques 512

Active Detection 513

Passive Detection 513

Proactive Defense 513

Basic Forensic Concepts 514

Policies and Procedures 516

Security Policies 517

Security Training 524

Patches and Upgrades 525

Firmware Updates 527

Driver Updates 527

File Hashing 528

Generating New Keys 528

Upgrading vs. Downgrading 528

Asset Disposal 530

Detection 531

Anti-malware Software 532

Host Based 533

Cloud/Server Based 533

Configuration Backups 534

Updating Antivirus Components 534

Fixing an Infected Computer 536

Summary 537

Exam Essentials 537

Written Lab 537

Review Questions 539

Chapter 15 Physical Security and Risk 543

Using Hardware and Software Security Devices 545

Defining Firewalls 547

Network-Based Firewalls 548

Host-Based Firewalls 548

Firewall Technologies 548

Access Control Lists 549

Port Security 551

Demilitarized Zone 552

Protocol Switching 553

Dynamic Packet Filtering 555

Proxy Services 556

Firewalls at the Application Layer vs. the Network Layer 558

Stateful vs. Stateless Network Layer Firewalls 559

NGFW/Layer7 Firewall 560

Scanning Services and Other Firewall Features 561

Content Filtering 562

Signature Identification 563

Context Awareness 563

Virtual Wire vs. Routed 563

Zones 564

Intrusion Detection and Prevention Systems 566

Network-Based IDS 567

Host-Based IDS 569

Vulnerability Scanners 570

VPN Concentrators 571

Understanding Problems Affecting Device Security 572

Physical Security 572

Logical Security Configurations 577

Risk-Related Concepts 579

Summary 586

Exam Essentials 587

Written Lab 588

Review Questions 589

Chapter 16 Wide Area Networks 593

What’s a WAN? 596

Defining WAN Terms 596

The Public Switched Telephone Network 598

WAN Connection Types 599

Bandwidth or Speed 600

T-Series Connections 601

The T1 Connection 602

The T3 Connection 603

Transmission Media 603

Wired Connections 603

Wavelength Division Multiplexing 604

Passive Optical Network 605

Wireless Technologies 605

Broadband Services 607

DSL Technology and xDSL 608

Cable Modem 610

Wireless WAN Technologies 611

Cellular WAN 612

WAN Protocols 613

Integrated Services Digital Network 613

Frame Relay Technology 615

Point-to-Point Protocol 618

DMVPN 621

SIP Trunks 621

Asynchronous Transfer Mode 622

MPLS 623

WAN Troubleshooting 623

Loss of Internet Connectivity 624

Interface Errors/Monitoring 624

Split Horizon 627

DNS Issues 628

Router Configurations 628

Company Security Policy 629

Summary 629

Exam Essentials 630

Written Lab 631

Review Questions 632

Chapter 17 Troubleshooting Tools 635

Protocol Analyzers 637

Throughput Testers 638

Connectivity Software 639

Using traceroute 640

Using ipconfig and ifconfig 642

Using the ifconfig Utility 646

Using the iptables utility 646

Using the ping Utility 647

Using the Address Resolution Protocol 650

The Windows ARP Table 651

Using the arp Utility 651

Using the nslookup Utility 654

Resolving Names with the Hosts Table 656

Using the Mtr Command (pathping) 657

Using the Nmap Utility 658

Using the route Command 659

Using the route Command Options 661

Some Examples of the route Command 662

Using the nbtstat Utility 663

The –a Switch 663

The –A Switch 665

The –c Switch 665

The –n Switch 666

The –r Switch 666

The –R Switch 667

The –S Switch 668

The –s Switch 668

Using the netstat Utility 669

The –a Switch 671

The –e Switch 672

The –r Switch 673

The –s Switch 673

The –p Switch 673

The –n Switch 675

Using tcpdump 676

Examples of Using tcpdump 676

Using the File Transfer Protocol 677

Starting FTP and Logging In to an FTP Server 678

Downloading Files 679

Uploading Files 681

Using the Telnet Utility 682

How to Enable Telnet in Windows 682

Don’t Use Telnet, Use Secure Shell 683

Summary 684

Exam Essentials 684

Written Lab 685

Review Questions 686

Chapter 18 Software and Hardware Tools 691

Understanding Network Scanners 693

Packet Sniffers/Network Monitors 693

Intrusion Detection and Prevention Software 695

Port Scanners 697

Wi-Fi Analyzer 700

Bandwidth Speed Tester 701

Baseline 702

Network Monitoring and Logging 703

Network Monitoring 703

SNMP 704

Syslog 705

SIEM 707

Utilization 710

Identifying Hardware Tools 712

Cable Testers 712

Protocol Analyzer 715

Certifiers 716

Time-Domain Reflectometer 717

Optical Time-Domain Reflectometer 717

Multimeter 718

Spectrum Analyzer 719

Toner Generator (Probe) 720

Metrics 721

Butt Set 721

Punch-Down Tool 722

Cable Stripper/Snips 723

Voltage Event Recorder (Power) 723

Environmental Monitors 724

Summary 725

Exam Essentials 725

Written Lab 726

Review Questions 727

Chapter 19 Network Troubleshooting 731

Narrowing Down the Problem 734

Did You Check the Super Simple Stuff? 735

Is Hardware or Software Causing the Problem? 738

Is It a Workstation or a Server Problem? 739

Which Segments of the Network Are Affected? 740

Is It Bad Cabling? 740

Troubleshooting Steps 749

Step 1: Identify the Problem 750

Step 2: Establish a Theory of Probable Cause 754

Step 3: Test the Theory to Determine Cause 762

Step 4: Establish a Plan of Action to Resolve the Problem and Identify Potential Effects 764

Step 5: Implement the Solution or Escalate as Necessary 766

Step 6: Verify Full System Functionality, and If Applicable, Implement Preventative Measures 769

Step 7: Document Findings, Actions, and Outcomes 769

Troubleshooting Tips 770

Don’t Overlook the Small Stuff 770

Prioritize Your Problems 771

Check the Software Configuration 771

Don’t Overlook Physical Conditions 772

Don’t Overlook Cable Problems 772

Check for Viruses 773

Summary 773

Exam Essentials 774

Written Lab 774

Review Questions 776

Chapter 20 Management, Monitoring, and Optimization 781

Managing Network Documentation 785

Using SNMP 785

Schematics and Diagrams 786

Network Monitoring 795

Baselines 795

Processes 796

On-Boarding and Off-Boarding of Mobile Devices 796

NAC 796

Policies, Procedures, and Regulations 797

Safety Practices 801

Implementing Network Segmentation 805

Network Optimization 808

Reasons to Optimize Your Network’s Performance 808

How to Optimize Performance 811

Unified Communications 813

Traffic Shaping 813

Load Balancing 814

High Availability 814

Caching Engines 815

Fault Tolerance 815

Archives/Backups 815

Common Address Redundancy Protocol 816

Virtual Networking 817

Locating and Installing Equipment 825

Change Management Procedures 832

Summary 834

Exam Essentials 835

Written Lab 836

Review Questions 837

Appendix A Answers to Written Labs 841

Chapter 1: Introduction to Networks 842

Chapter 2: The Open Systems Interconnection Specifications 842

Chapter 3: Networking Topologies, Connectors, and Wiring Standards 843

Chapter 4: The Current Ethernet Specifications 843

Chapter 5: Networking Devices 845

Chapter 6: Introduction to the Internet Protocol 846

Chapter 7: IP Addressing 847

Written Lab 7.1 847

Written Lab 7.2 847

Written Lab 7.3 848

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

Chapter 9: Introduction to IP Routing 849

Chapter 10: Routing Protocols 849

Chapter 11: Switching and Virtual LANs 850

Chapter 12: Wireless Networking 850

Chapter 13: Authentication and Access Control 850

Chapter 14: Network Threats and Mitigation 851

Chapter 15: Physical Security and Risk 851

Chapter 16: Wide Area Networks 852

Chapter 17: Troubleshooting Tools 852

Chapter 18: Software and Hardware Tools 853

Chapter 19: Network Troubleshooting 853

Chapter 20: Management, Monitoring, and Optimization 854

Appendix B Answers to Review Questions 855

Chapter 1: Introduction to Networks 856

Chapter 2: The Open Systems Interconnection Specifications 857

Chapter 3: Networking Topologies, Connectors, and Wiring Standards 859

Chapter 4: The Current Ethernet Specifications 860

Chapter 5: Networking Devices 861

Chapter 6: Introduction to the Internet Protocol 863

Chapter 7: IP Addressing 864

Chapter 8: IP Subnetting, Troubleshooting IP, and Introduction to NAT 866

Chapter 9: Introduction to IP Routing 868

Chapter 10: Routing Protocols 869

Chapter 11: Switching and Virtual LANs 871

Chapter 12: Wireless Networking 872

Chapter 13: Authentication and Access Control 874

Chapter 14: Network Threats and Mitigation 875

Chapter 15: Physical Security and Risk 877

Chapter 16: Wide Area Networks 878

Chapter 17: Troubleshooting Tools 880

Chapter 18: Software and Hardware Tools 881

Chapter 19: Network Troubleshooting 883

Chapter 20: Management, Monitoring, and Optimization 885

Appendix C Subnetting Class A 887

Subnetting Practice Examples: Class A Addresses 888

Practice Example #1A: 255.255.0.0 (/16) 888

Practice Example #2A: 255.255.240.0 (/20) 889

Practice Example #3A: 255.255.255.192 (/26) 889

Subnetting in Your Head: Class A Addresses 890

Written Lab 1 891

Written Lab 2 892

Answers to Written Lab 1 892

Answers to Written Lab 2 893

Index 895