Tài liệu Managing Cisco Network Security P1 pdf

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CISCO
NETWORK
SECURITY
MANAGING
Russell Lusignan, CCNP, CCNA, MCSE, MCP+I, CNA
Oliver Steudler, CCNA, CCDA, CNE
Jacques Allison, CCNP, ASE, MCSE+I
TECHNICAL EDITOR:
Florent Parent, Network Security Engineer, Viagénie Inc.
“Finally! A single resource that really
delivers solid and comprehensive
knowledge on Cisco security planning
and implementation. A must have for the
serious Cisco library.”
—David Schaer, CCSI, CCNP, CCDA, MCSE, MCDBA,
MCNI, MCNE, CCA
President, Certified Tech Trainers
1 YEAR UPGRADE
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112_IpSec_FM 11/8/00 8:52 AM Page ii

MANAGING
CISCO
NETWORK SECURITY:
BUILDING ROCK-SOLID
NETWORKS
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Managing Cisco Network Security: Building Rock-Solid Networks
Copyright © 2000 by Syngress Publishing, Inc. All rights reserved. Printed in the United States of America.
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v
Acknowledgments
We would like to acknowledge the following people for their kindness and sup-
port in making this book possible.
Richard Kristof, Duncan Anderson, Jennifer Gould, Robert Woodruff, Kevin
Murray, Dale Leatherwood, Rhonda Harmon, and Robert Sanregret of Global
Knowledge, for their generous access to the IT industry’s best courses,
instructors and training facilities.
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works.
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Publishers Group West for sharing their incredible marketing experience and
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making certain that our vision remains worldwide in scope.
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Australia for all their help.
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Special thanks to the professionals at Osborne with whom we are proud to
publish the best-selling Global Knowledge Certification Press series.
v
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vi
From Global Knowledge
At Global Knowledge we strive to support the multiplicity of learning styles
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President and Chief Executive Officer, Global Knowledge
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vii
Contributors
Russell Lusignan (CCNP, CCNA, MCSE, MCP+I, CNA) is a Senior
Network Engineer for Bird on a Wire Networks, a high-end dedi-
cated and fully managed Web server/ASP provider located in
Toronto, Canada. He is also a technical trainer for the Computer
Technology Institute.
Russell’s main area of expertise is in LAN routing and
switching technologies and network security implementations.
Chapters 3, 4, and 6.
David G. Schaer (CCNA, CCDA, CCNP, CCSI, MCT, MCSE,
MCP+I, MCNE, CCA) is President of Certified Tech Trainers, Inc.,
an organization specializing in the development and delivery of
custom training for Cisco CCNA and CCNP certification. He has
provided training sessions for major corporations throughout the
United States, Europe, and Central America. David enjoys kayak
fishing, horseback riding, and exploring the Everglades.
Oliver Steudler (CCNA, CCDA, CNE) is a Senior Systems
Engineer at iFusion Networks in Cape Town, South Africa. He

has over 10 years of experience in designing, implementing and
troubleshooting complex networks.
Chapter 5.
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viii
Jacques Allison (CCNP, ASE, MCSE+I) Jacques has been
involved with Microsoft-related projects on customer networks
ranging from single domain and exchange organization migra-
tions to IP addressing and network infrastructure design and
implementation. Recently he has worked on CA Unicenter TNG
implementations for network management.
He received his engineering diploma in Computer Systems in
1996 from the Technicon Pretoria in South Africa. Jacques
began his career with Electronic Data Systems performing
desktop support, completing his MCSE in 1997.
Jacques would like to dedicate his contribution for this book to
his fiancée, Anneline, who is always there for him. He would also
like to thank his family and friends for their support.
Chapter 8.
John Barnes (CCNA, CCNP, CCSI) is a network consultant and
instructor. John has over ten years experience in the implemen-
tation, design, and troubleshooting of local and wide area net-
works as well as four years of experience as an instructor.
John is a regular speaker at conferences and gives tutorials
and courses on IPv6, IPSec, and intrusion detection. He is cur-
rently pursuing his CCIE. He would like to dedicate his efforts
on this book to his daughter, Sydney.
Chapter 2.
Russell Gillis (CISSP, MCSE, CCNA) is Associate Director of
Networking at Kalamazoo College in Kalamazoo, Michigan.

Prior to joining “K” College, Russ worked for 11 years in the
pharmaceutical industry. His experience includes workstation
support, system administration, network design, and information
security.
Chapter 1.
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ix
Pritpal Singh Sehmi lives in London, England. He has worked
in various IT roles and in 1995 launched Spirit of Free
Enterprise, Ltd. Pritpal is currently working on an enterprise
architecture redesign project for a large company. Pritpal is also
a freelance Cisco trainer and manages the Cisco study group
www.ccguru.com. Pritpal owes his success to his family and life-
long friend, Vaheguru Ji.
Chapter 7.
Technical Editor
Florent Parent is currently working at Viagénie, Inc. as a con-
sultant in network architecture and security for a variety of orga-
nizations, corporations, and governments. For over 10 years, he
has been involved in IP networking as a network architect, net-
work manager, and educator.
He is involved in the architecture development and deploy-
ment of IPv6 in the CA*net network and the 6Tap IPv6 exchange.
Florent participates regularly in the Internet Engineering Task
Force (IETF), especially in the IPv6 and IPSec work groups.
In addition to acting as technical editor for the book, Florent
authored the Preface and Chapter 9.
Technical Reviewer
Stace Cunningham (CMISS, CCNA, MCSE, CLSE, COS/2E,
CLSI, COS/2I, CLSA, MCPS, A+) is a security consultant cur-

rently located in San Antonio, TX. He has assisted several
clients, including a casino, in the development and implementa-
tion of network security plans for their organizations. He held
the positions of Network Security Officer and Computer Systems
Security Officer while serving in the United States Air Force.
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While in the Air Force, Stace was involved for over 14 years in
installing, troubleshooting, and protecting long-haul circuits
ensuring the appropriate level of cryptography necessary to pro-
tect the level of information traversing the circuit as well the cir-
cuits from TEMPEST hazards. This included American
equipment as well as equipment from Britain and Germany while
he was assigned to Allied Forces Southern Europe (NATO).
Stace has been an active contributor to The SANS Institute
booklet “Windows NT Security Step by Step.” In addition, he has
co-authored or served as the Technical Editor for over 30 books
published by Osborne/McGraw-Hill, Syngress Media, and
Microsoft Press. He is also a published author in “Internet
Security Advisor” magazine.
His wife Martha and daughter Marissa have been very sup-
portive of the time he spends with the computers, routers, and
firewalls in the “lab” of their house. Without their love and sup-
port, he would not be able to accomplish the goals he has set for
himself.
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Contents
xi
Preface xxi
Chapter 1 Introduction to IP Network Security 1

Introduction 2
Protecting Your Site 2
Typical Site Scenario 5
Host Security 7
Network Security 9
Availability 10
Integrity 11
Confidentiality 12
Access Control 12
Authentication 13
Authorization 14
Accounting 15
Network Communication in TCP/IP 15
Application Layer 17
Transport Layer 18
TCP 18
TCP Connection 20
UDP 21
Internet Layer 22
IP 22
ICMP 23
ARP 23
Network Layer 24
Security in TCP/IP 24
Cryptography 24
Symmetric Cryptography 25
Asymmetric Cryptography 26
Hash Function 26
Public Key Certificates 27
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