CompTIA Network+ Study Guide Second Edition WILEY John Wiley & Sons, Inc.
Foreword Introduction Assessment Test xxv xxix li Chapter 1 Introduction to Networks 1 First Things First: What's a Network? 2 The Local Area Network (LAN) 3 Common Network Components 5 Wide Area Network (WAN) 7 Network Architecture: Peer-to-Peer or Client-Server? 9 Physical Network Topologies 12 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 18 Selecting the Right Topology 19 The Network Backbone 20 Network Segments 21 Summary 21 Exam Essentials 21 Written Labs 22 Review Questions 23 Chapter 2 The Open Systems Interconnection Specifications 27 Internetworking Models 28 The Layered Approach 28 Advantages of Reference Models 29 The OSI Reference Model 30 The Application Layer 31 The Presentation Layer 33 The Session Layer 33 The Transport Layer 33 T he Network Layer 39 The Data Link Layer 42 The Physical Layer 44 Introduction to Encapsulation 45
xii Summary 46 Exam Essentials 46 Written Lab 47 Review Questions 48 Chapter 3 Networking Topologies, Connectors, and Wiring Standards 53 Physical Media 55 Coaxial Cable 55 Twisted-Pair Cable 58 Fiber-Optic Cable 61 Media Converters 66 Broadband over Power Line 67 Serial Cables 68 Cable Properties 71 Transmission Speeds 71 Distance 71 Duplex 71 Noise Immunity (Security, EMI) 71 Frequency 72 Wiring Standards 72 568A vs. 568B 73 Straight-Through Cable 75 Crossover Cable 75 Tl Crossover Cable 76 Installing Wiring Distributions 79 Summary 80 Exam Essentials 81 Written Lab 81 Review Questions 83 Chapter 4 The Current Ethernet Specifications 87 Network Basics 88 Ethernet Basics 90 Collision Domain 90 Broadcast Domain 90 CSMA/CD 91 Half- and Full-Duplex Ethernet 92 Ethernet at the Data Link Layer 94 Binary to Decimal and Hexadecimal Conversion 94 Ethernet Addressing 98 Ethernet Frames 98 Channel Bonding 101 Ethernet at the Physical Layer 101 Summary 106
xiii Exam Essentials 107 Written Lab 107 Review Questions 111 Chapter 5 Networking Devices 115 Common Network Connectivity Devices 117 Hub 118 Network Interface Card 118 Bridge 120 Switch 120 Router 121 Firewall 125 Dynamic Host Configuration Protocol Server 126 Other Specialized Devices 129 Multilayer Switch 130 Load Balancer 130 Domain Name Service Server 130 Proxy Server 135 Encryption Devices 136 VPN Concentrator 137 Planning and Implementing a Basic SOHO Network Using Network Segmentation 137 Determining Requirements 138 Switches and Bridges at the Data Link Layer 144 Hubs at the Physical Layer 146 Environmental Considerations 147 Summary 147 Exam Essentials 148 Written Lab 149 Review Questions 150 Chapter 6 Introduction to the Internet Protocol 155 Introducing TCP/IP 157 A Brief History of TCP/IP 157 TCP/IP and the DoD Model 158 The Process/Application Layer Protocols 159 The Host-to-Host Layer Protocols 168 The Internet Layer Protocols 173 Data Encapsulation 178 Summary 182 Exam Essentials 182 Written Lab 183 Review Questions 184
xiv Chapter 7 IP Addressing 189 IP Terminology 190 The Hierarchical IP Addressing Scheme 191 Network Addressing 192 Private IP Addresses 196 IPv4 Address Types 198 Layer 2 Broadcasts 198 Layer 3 Broadcasts 198 Unicast Address 199 Multicast Address 199 Internet Protocol Version 6 (IPv6) 200 Why Do We Need IPv6? 200 The Benefits of and Uses for IPv6 201 IPv6 Addressing and Expressions 202 Shortened Expression 203 Address Types 203 Special Addresses 204 Summary 205 Exam Essentials 205 Written Lab 206 Review Questions 207 Chapter 8 IP Subnetting, Troubleshooting IP, and Introduction to NAT 211 Subnetting Basics 212 How to Create Subnets 213 Subnet Masks 214 Classless Inter-Domain Routing (CIDR) 215 Subnetting Class C Addresses 217 Subnetting Class B Addresses 226 Troubleshooting IP Addressing 234 Determining IP Address Problems 237 Introduction to Network Address Translation (NAT) 241 Types of Network Address Translation 243 NAT Names 243 How NAT Works 244 Summary 245 Exam Essentials 246 Written Labs 246 Review Questions 247
xv Chapter 9 Introduction to IP Routing 253 Routing Basics 254 The IP Routing Process 257 Testing Your IP Routing Understanding 263 Static and Dynamic Routing 264 Summary 267 Exam Essentials 267 Written Lab 267 Review Questions 269 Chapter 10 Routing Protocols 273 Routing Protocol Basics 274 Administrative Distances 275 Classes of Routing Protocols 277 Distance Vector Routing Protocols 278 Routing Information Protocol (RIP) 279 RIP Version 2 (RIPv2) 280 VLSM and Discontiguous Networks 280 EIGRP 282 Border Gateway Protocol (BGP) 285 Link State Routing Protocols 286 Open Shortest Path First (OSPF) 287 Intermediate System-to-intermediate System (IS-IS) 289 IPv6 Routing Protocols 290 RIPng 290 EIGRPv6 291 OSPFv3 291 Summary 291 Exam Essentials 292 Written Lab 292 Review Questions 293 Chapter 11 Switching and Virtual LANs 297 Networking Before Layer 2 Switching 298 Switching Services 302 Limitations of Layer 2 Switching 303 Bridging vs. LAN Switching 303 Three Switch Functions at Layer 2 304 Spanning Tree Protocol 309 Sparming-Tree Port States 310 STr Convergence 311 Rapid Spanning Tree Protocol 802.lw 311
xvi Virtual LANs 313 VLAN Basics 313 Quality of Service 316 VLAN Memberships 317 Static VLANs 317 Dynamic VLANs 318 Identifying VLANs 318 VLAN Identification Methods 320 VLAN Trunking Protocol 321 VTP Modes of Operation 322 Configuring VTP 323 Two Additional Advanced Features of Switches 324 Power over Ethernet 324 Port Mirroring/Spanning 326 Summary 328 Exam Essentials 328 Written Lab 329 Review Questions 330 Chapter 12 Wireless Networking 335 Introduction to Wireless Technology 337 The 802.11 Standards 340 2.4GHz (802.11b) 341 2.4GHz (802.11g) 342 5GHz (802.11a) 343 5GHz(802.11h) 344 2.4GHz/5GHz (802.lln) 345 Comparing 802.11 Standards 346 Range Comparisons 346 Wireless Network Components 347 Wireless Access Points 347 Wireless Network Interface Card 348 Wireless Antennas 349 Installing a Wireless Network 351 Ad Hoc Mode: Independent Basic Service Set 351 Infrastructure Mode: Basic Service Set 352 Signal Degradation 354 Installing and Configuring Hardware 355 Wireless Security 362 Open Service Set Identifiers, Wired Equivalent Privacy, Access 363 and Media Access Control Address Authentication 364 Remote Authentication Dial In User Service 365
xvii Temporal Key Integrity Protocol 366 Wi-Fi Protected Access or WPA 2 Pre-Shared Key 367 Summary 368 Exam Essentials 369 Written Lab 369 Review Questions 370 Chapter 13 Authentication and Access Control 375 Security Filtering 377 Access Control Lists 378 Tunneling 379 Encryption 386 Remote Access 390 Managing User Account and Password Security 393 Managing User Accounts 393 Managing Passwords 396 Single Sign-On 400 Multifactor Authentication 400 User-Authentication Methods 400 Public Key Infrastructure (PKI) 401 Kerberos 402 Authentication, Authorization, and Accounting (AAA) 402 Network Access Control (NAC) 405 Challenge Handshake Authentication Protocol (CHAP) 405 MS-CHAP 405 Extensible Authentication Protocol (EAP) 406 Summary 406 Exam Essentials 407 Written Lab 407 Review Questions 409 Chapter 14 Network Threats and Mitigation 413 Recognizing Security Threats 414 Denial of Service 415 Viruses 417 Worms 421 Buffer Overflow 421 Wireless Threats 421 Attackers and Their Tools 424 Social Engineering (Phishing) 427 Understating Mitigation Techniques 428 Active Detection 429 Passive Detection 429 Proactive Defense 429
xviii Policies and Procedures 430 Security Policies 431 Security Training 436 Patches and Upgrades 437 Updating Antivirus Components 439 Fixing an Infected Computer 441 Summary 441 Exam Essentials 442 Written Lab 442 Review Questions 444 Chapter 15 Physical and Hardware Security 449 Using Hardware and Software Security Devices 450 Defining Firewalls 452 Network-Based Firewalls 453 Host-Based Firewalls 453 Firewall Technologies 453 Access Control Lists 453 Port Security 456 Demilitarized Zone 456 Protocol Switching 457 Dynamic Packet Filtering 459 Proxy Services 460 Firewalls at the Application Layer vs. the Network Layer 461 Stateful vs. Stateless Network Layer Firewalls 462 Application Layer Firewalls 463 Scanning Services and Other Firewall Features 464 Content Filtering 465 Signature Identification 466 Zones 466 Intrusion Detection and Prevention Systems 468 Network-Based IDS 469 Host-Based IDS 471 Vulnerability Scanners 472 VPN Concentrators 473 Understanding Problems Affecting Device Security 474 Physical Security 474 Logical Security Configurations 476 Summary 478 Exam Essentials 479 Written Lab 480 Review Questions 481
xix Chapter 16 Wide Area Networks 485 What's a WAN? 488 Defining WAN Terms 488 The Public Switched Telephone Network 489 WAN Connection Types 490 Bandwidth or Speed 492 T-Series Connections 492 The Tl Connection 494 The T3 Connection 494 Transmission Media 495 Wired Connections 495 Dense Wavelength Division Multiplexing 496 Passive Optical Network 496 Wireless Technologies 497 Broadband Services 498 DSL Technology and xdsl 500 Cable Modem 501 Wireless WAN Technologies 503 Cellular WAN 503 WAN Protocols 504 Integrated Services Digital Network 504 Frame Relay Technology 506 Asynchronous Transfer Mode 508 Summary 509 Exam Essentials 509 Written Lab 510 Review Questions 511 Chapter 17 Troubleshooting Tools 515 Protocol Analyzers 517 Throughput Testers 518 Connectivity Software 519 Using Traceroute 520 Using ipconfig and ifconfig 521 Using the ipconfig Utility 521 Using the ifconfig Utility 525 Using the ping Utility 526 Using the Address Resolution Protocol 529 The Windows ARP Table 529 Using the arp Utility 530 Using the nslookup Utility 533 Resolving Names with the Hosts Table 535 Using the Mtr Command 536
xx Using the route Command 537 Using the route Command Options 538 Some Examples of the route Command 540 Using the nbtstat Utility 540 The -a Switch 541 The -A Switch 543 The -c Switch 543 The -n Switch 544 The -r Switch 544 The -R Switch 545 The -5 Switch 545 The -s Switch 546 Using the netstat Utility 546 The -a Switch 549 The -e Switch 550 The -r Switch 551 The -s Switch 551 The -p Switch 551 The -n Switch 553 Using the File Transfer Protocol 554 Starting FTP and Logging In to an FTP Server 555 Downloading Files 557 Uploading Files 559 Using the Telnet Utility 560 How to Enable Telnet in Vista 560 Don't Use Telnet, Use Secure Shell 561 Summary 562 Exam Essentials 562 Written Lab 563 Review Questions 564 Chapter 18 Software and Hardware Tools 569 Understanding Network Scanners 570 Packet Sniffers 570 Intrusion Detection and Prevention Software 572 Port Scanners 574 Identifying Hardware Tools 576 Cable Testers 577 Protocol Analyzer 579 Certifiers 580 Time-Domain Reflectometer 581 Optical Time-Domain Reflectometer 581
xxi Multimeter 582 Toner Probe 582 Butt Set 584 Punch-Down Tool 585 Cable Stripper/Snips 586 Voltage Event Recorder 587 Environmental Monitors 588 Summary 589 Exam Essentials 589 Written Lab 590 Review Questions 591 Chapter 19 Network Troubleshooting 595 Narrowing Down the Problem 598 Are There Any Cabling Issues? Did You Check the Super Simple Stuff? 599 Is Hardware or Software Causing the Problem? 603 Is It a Workstation or a Server Problem? 604 Which Segments of the Network Are Affected? 604 Is It Bad Cabling? 604 Troubleshooting Steps 609 Step 1: Identify the Problem 610 Step 2: Establish a Theory of Probable Cause 613 Step 3: Test the Theory to Determine Cause 616 Step 4: Establish a Plan of Action to Resolve the Problem and Identify Potential Effects 618 Step 5: Implement the Solution or Escalate as Necessary 620 Step 6: Verify Full System Functionality and If Applicable Implement Preventative Measures 622 Step 7: Document Findings, Actions, and Outcomes 623 Troubleshooting Tips 623 Don't Overlook the Small Stuff 624 Prioritize Your Problems 624 Check the Software Configuration 625 Don't Overlook Physical Conditions 625 Don't Overlook Cable Problems 626 Check for Viruses 626 Summary 626 Exam Essentials 627 Written Lab 628 Review Questions 629
xxii Chapter 20 Management, Monitoring, and Optimization 635 Managing Network Documentation 638 Using SNMP 638 Schematics and Diagrams 639 Baselines 645 Policies, Procedures, and Regulations 647 Monitoring the Network and Optimizing Its Performance 649 Network Monitoring and Logging 650 Reasons to Optimize Your Network's Performance 652 How to Optimize Performance 654 Virtual Networking 658 Summary 661 Exam Essentials 662 Written Lab 663 Review Questions 664 Appendix A Answers to Review Questions 669 Chapter 1: Introduction to Networks 670 Chapter 2: The Open Systems Interconnection Specifications 672 Chapter 3: Networking Topologies, Connectors, and Wiring Standards 673 Chapter 4: The Current Ethernet Specifications 675 Chapter 5: Networking Devices 676 Chapter 6: Introduction to the Internet Protocol 677 Chapter 7: IP Addressing 679 Chapter 8: IP Subnetting, Troubleshooting IP, and Introduction to NAT 681 Chapter 9: Introduction to IP Routing 683 Chapter 10: Routing Protocols 684 Chapter 11: Switching and Virtual LANs 686 Chapter 12: Wireless Networking 688 Chapter 13: Authentication and Access Control 689 Chapter 14: Network Threats and Mitigation 691 Chapter 15: Physical and Hardware Security 692 Chapter 16: Wide Area Networks 694 Chapter 17: Troubleshooting Tools 695 Chapter 18: Software and Hardware Tools 697 Chapter 19: Network Troubleshooting 699 Chapter 20: Management, Monitoring, and Optimization 700 Appendix B Answers to Written Labs 703 Chapter 1: Introduction to Networks 704 Chapter 2: The Open Systems Interconnection Specifications 704 Chapter 3: Networking Topologies, Connectors, and Wiring Standards 705
xxiii Chapter 4: The Current Ethernet Specifications 705 Chapter 5: Networking Devices 708 Chapter 6: Introduction to the Internet Protocol 708 Chapter 7: IP Addressing 709 Chapter 8: IP Subnetting, Troubleshooting IP, and Introduction to NAT 710 Chapter 9: Introduction to IP Routing 710 Chapter 10: Routing Protocols 711 Chapter 11: Switching and Virtual LANs 711 Chapter 12: Wireless Networking 712 Chapter 13: Authentication and Access Control 712 Chapter 14: Network Threats and Mitigation 712 Chapter 15: Physical and Hardware Security 713 Chapter 16: Wide Area Networks 713 Chapter 17: Troubleshooting Tools 714 Chapter 18: Software and Hardware Tools 714 Chapter 19: Network Troubleshooting 715 Chapter 20: Management, Monitoring, and Optimization 715 Appendix C Subnetting Class A 717 Subnetting Practice Examples: Class A Addresses 718 Practice Example #1A: 255.255.0.0 (/16) 719 Practice Example #2A: 255.255.240.0 (/20) 719 Practice Example #3A: 255.255.255.192 (116) 720 Subnetting in Your Head: Class A Addresses 720 Written Lab 1 721 Written Lab 2 722 Answers to Written Lab 1 722 Answers to Written Lab 2 723 Appendix D About the Additional Study Tools 725 Additional Study Tools 726 Sybex Test Engine 726 Electronic Flashcards 726 PDF of Glossary of Terms 726 Adobe Reader 726 System Requirements 727 Using the Study Tools 727 Troubleshooting 727 Customer Care 728 Index 729