CompTIA Network+ Certification Study Guide, Fourth Edition

801 Pages·2009·27.04 MB·English

®
CompTIA Network+
Certification Study Guide,
Fourth Edition
Glen E. Clarke
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To my beautiful wife, Tanya, who continues to show amazing patience and support.
You are a true inspiration!
About the Author
Glen E. Clarke, MCSE/MCSD/MCDBA/MCT/CEH/SCNP/Security+/
Network+/A+, is an independent trainer and consultant, focusing on
network security and security auditing services. Glen spends most of
his time delivering certified courses on Windows Server, SQL Server,
Exchange Server, Visual Basic .NET, and ASP.NET. Glen also teaches a
number of security-related courses covering topics such as ethical hacking,
vulnerability testing, firewall design, and packet analysis topics.
Glen is an experienced author and technical editor whose published
work has been nominated for a referenceware excellence award in 2003 and
2004. Glen has worked on a number of certification titles, including topics
on A+ certification, Windows 2000/2003 certification, and Network+ and
Security+ certification.
When he’s not working, Glen loves to spend quality time with his wife,
Tanya, and their four children, Sara, Brendon, Ashlyn, and Rebecca. He
is an active member of High Technology Crime Investigation Association
(HTCIA). You can visit Glen online at www.gleneclarke.com, or contact
him at
Contents At A GLAnCe
1 Basic Network Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Network P rotocols and Standards . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3 Networking C omponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
4 TCP/IP F undamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
5 Subnetting and Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
6 TCP/IP Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
7 Wireless N etworking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
8 Remote C onnectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
9 Wide Area N etwork T echnologies . . . . . . . . . . . . . . . . . . . . . . . . . . 437
10 Implementing a Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
11 Maintaining and Supporting a N etwork . . . . . . . . . . . . . . . . . . . . . . 533
12 Network Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
13 Troubleshooting the Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685
A About the CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 743
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 747
v
Contents
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxii
1 basic network Concepts . . . . . . . . . . . . . . . . . . . . . . . 1
Identifying Characteristics of a Network . . . . . . . . . . . . . . . . . . . . . . 2
Servers, Workstations, and Hosts . . . . . . . . . . . . . . . . . . . . . 2
WANs, LANs, and MANs . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Types of Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Internet, Intranet, and Extranet . . . . . . . . . . . . . . . . . . . . . . 8
Identifying Network Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Bus Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Star Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Mesh Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Ring Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Hybrid Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Wireless Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Point-to-Point and Point-to-Multipoint . . . . . . . . . . . . . . . . 18
Segments and Backbones . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Network Media and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Coaxial Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Twisted-Pair Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
exercise 1-1: Crimping a Category 5 Cable . . . . . . . . . . . . 28
Fiber-Optic Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Connector Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Access Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
CSMA/CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
CSMA/CA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Token Passing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
vi
Contents vii
Network Architectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Broadband and Baseband . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Token Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
FDDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Network Operating Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Windows Servers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Novell NetWare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
UNIX/Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3 Two-Minute Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Q&A Self Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Self Test Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
2 Network Protocols and Standards . . . . . . . . . . . . . . . 71
Network Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
NetBEUI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
What Is NetBIOS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
IPX/SPX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
AppleTalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
TCP/IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Routable vs. Nonroutable Protocols . . . . . . . . . . . . . . . . . . . 78
The OSI Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Layer 7: The Application Layer . . . . . . . . . . . . . . . . . . . . . . 81
Layer 6: The Presentation Layer . . . . . . . . . . . . . . . . . . . . . . 82
Layer 5: The Session Layer . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Layer 4: The Transport Layer . . . . . . . . . . . . . . . . . . . . . . . . 83
Layer 3: The Network Layer . . . . . . . . . . . . . . . . . . . . . . . . . 84
Layer 2: The Data Link Layer . . . . . . . . . . . . . . . . . . . . . . . . 85
Layer 1: The Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . . 86
Protocols and the OSI Layers . . . . . . . . . . . . . . . . . . . . . . . . 86
Exercise 2-4: Viewing Protocol Information with
Network Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
802 Project Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
IEEE 802 Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Certification Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
3 Two-Minute Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Q&A Self Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Self Test Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
viii Network+ Certifcation Study Guide
3 networking C omponents . . . . . . . . . . . . . . . . . . . . . . 115
Network Interface Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Transceivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
MAC A ddress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
exercise 3-2: Determining Your Local Machine’s MAC
Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Troubleshooting Network Cards . . . . . . . . . . . . . . . . . . . . . . 127
Hubs, MAUs, and Repeaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Multistation Access Units . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Repeaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Bridges and Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Routers and Brouters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Brouters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Gateways and Security Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Gateways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Firewalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Intrusion Detection Systems . . . . . . . . . . . . . . . . . . . . . . . . . 148
Other Networking Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Wireless Access Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
CSU/DSU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
ISDN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Wiring Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Certification Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
3 Two-Minute Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Q&A Self Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Self Test Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
4 tCP/IP F undamentals . . . . . . . . . . . . . . . . . . . . . . . . . 169
TCP/IP Protocol Suite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
The TCP/IP Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Application-Layer Protocols . . . . . . . . . . . . . . . . . . . . . . . . . 174
TCP/IP Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
TCP/IP Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Contents ix
TCP/IP Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Understanding Binary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Address Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
Loopback Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Private Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Addressing Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
IPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
TCP/IP Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Exercise 4-5: Viewing TCP/IP Port Values . . . . . . . . . . . . 191
TCP/IP Configuration Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Manual Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Dynamic Host Configuration Protocol (DHCP) . . . . . . . . . . 194
APIPA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Boot Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Domain Name System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Windows Internet Naming Service . . . . . . . . . . . . . . . . . . . . 201
Configuring a Linux Machine for TCP/IP . . . . . . . . . . . . . . . 203
Network Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
DHCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
DNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
WINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
NAT/PAT/SNAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
ICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
SMB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
NFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
AFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Samba . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
ZeroConfig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Certification Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
3 Two-Minute Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Q&A Self Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Self Test Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
5 Subnetting and Routing . . . . . . . . . . . . . . . . . . . . . . . . 229
Understanding Subnetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Exercise 5-1: Subnetting a Class A Address . . . . . . . . . . . 238
Classful vs. Classless Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
CIDR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Supernetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246