Cover image for Firewalls for dummies
Firewalls for dummies
Komar, Brian.
Personal Author:
Second edition.
Publication Information:
New York : Wiley Pub., [2003]

Physical Description:
xvi, 411 pages : illustrations ; 24 cm.
General Note:
Includes index.
Electronic Access:
Table of contents
Format :


Call Number
Material Type
Home Location
Item Holds
TK5105.59 .K66 2003 Adult Non-Fiction Computer Books

On Order



What an amazing world we live in! Almost anything you can imagine can be researched, compared, admired, studied, and in many cases, bought, with the click of a mouse. The Internet has changed our lives, putting a world of opportunity before us. Unfortunately, it has also put a world of opportunity into the hands of those whose motives are less than honorable. A firewall, a piece of software or hardware that erects a barrier between your computer and those who might like to invade it, is one solution.

If you've been using the Internet for any length of time, you've probably received some unsavory and unsolicited e-mail. If you run a business, you may be worried about the security of your data and your customers? privacy. At home, you want to protect your personal information from identity thieves and other shady characters. Firewalls For Dummies#65533; will give you the lowdown on firewalls, then guide you through choosing, installing, and configuring one for your personal or bus iness network.

Firewalls For Dummies#65533; helps you understand what firewalls are, how they operate on different types of networks, what they can and can't do, and how to pick a good one (it's easier than identifying that perfect melon in the supermarket.) You'll find out about

Developing security policies Establishing rules for simple protocols Detecting and responding to system intrusions Setting up firewalls for SOHO or personal use Creating demilitarized zones Using Windows or Linux as a firewall Configuring ZoneAlarm, BlackICE, and Norton personal firewalls Installing and using ISA server and FireWall-1

With the handy tips and hints this book provides, you'll find that firewalls are nothing to fear ? that is, unless you're a cyber-crook! You'll soon be able to keep your data safer, protect your family's privacy, and probably sleep better, too.

Author Notes

Brian Komar owns a network security consulting firm
Ronald Beekelaar is a security and firewall implementation trainer
Joern Wettern, PhD, has advised both small and multi-national businesses

Table of Contents

Introductionp. 1
About This Bookp. 2
How to Use This Bookp. 2
What You Don't Need to Readp. 2
Foolish Assumptionsp. 2
How This Book Is Organizedp. 3
Icons Used in This Bookp. 5
Where to Go from Herep. 5
Part I Introducing Firewall Basicsp. 7
Chapter 1 Why Do You Need a Firewall?p. 9
Defining a Firewallp. 9
The Value of Your Networkp. 11
Get Yourself Connectedp. 12
TCP/IP Basicsp. 18
What Firewalls Dop. 19
What Firewalls Look Likep. 20
Rules, Rules, Everywhere Rulesp. 22
Chapter 2 IP Addressing and Other TCP/IP Basicsp. 23
How Suite It Is: The TCP/IP Suite of Protocolsp. 24
Peeling Away the Protocol Layersp. 26
The Numbers Game: Address Basicsp. 28
URLs: How to Reference Resourcesp. 32
Understanding IP Addressesp. 33
Private IP Addressesp. 36
Dissecting Network Traffic: The Anatomy of an IP Packetp. 37
Transport Layer Protocolsp. 39
Application Layer Protocolsp. 42
The Keeper of the Protocolsp. 45
Putting It All Together: How a Request Is Processedp. 46
Chapter 3 Understanding Firewall Basicsp. 47
What Firewalls Do (And Where's the Fire, Anyway?)p. 48
General Strategy: Allow-All or Deny-Allp. 51
Packet Filteringp. 54
Network Address Translation (NAT)p. 62
Application Proxyp. 65
Monitoring and Loggingp. 68
Chapter 4 Understanding Firewall Not-So-Basicsp. 71
Making Internal Servers Available: Static Address Mappingp. 73
Filtering Content and Morep. 76
Detecting Intrusionp. 79
Improving Performance by Caching and Load Balancingp. 83
Using Encryption to Prevent Modification or Inspectionp. 88
Chapter 5 "The Key Is under the Mat" and Other Common Attacksp. 97
Intrusion Attacks: A Stranger in the Housep. 97
Denial-of-service Attacksp. 99
How Hackers Get Inp. 101
Can a Firewall Really Protect Me?p. 109
Are You Scared Yet?p. 110
Part II Establishing Rulesp. 111
Chapter 6 Developing Policiesp. 113
Defining an Internet Acceptable Use Policyp. 114
Defining a Security Policyp. 118
Chapter 7 Establishing Rules for Simple Protocolsp. 121
For Starters, Some Default Rulesp. 123
Allowing Web Accessp. 123
Finding Internet Resourcesp. 126
File Transfer Protocol (FTP)p. 131
Messaging and Conferencingp. 133
Thin Client Solutionsp. 137
Internet Control Message Protocol (ICMP)p. 139
Chapter 8 Designing Advanced Protocol Rulesp. 143
Rain, Sleet, Snow, and Firewalls: Getting the E-Mail Throughp. 144
Knock, Knock: Who Goes There?p. 149
IPSec Encryptionp. 152
Let Me In: Tunneling through the Internetp. 158
Chapter 9 Configuring "Employees Only" and Other Specific Rulesp. 163
Limiting Access by Users: Not All Are Chosenp. 163
Filtering Types of Contentp. 165
Filtering Other Contentp. 166
Setting the Clock: Filtering on Date/Timep. 168
Part III Designing Network Configurationsp. 169
Chapter 10 Setting Up Firewalls for SOHO or Personal Usep. 171
No-Box Solution: ISP Firewall Servicep. 171
Single-Box Solution: Dual-Homed Firewallp. 172
Screened Hostp. 173
Deployment Scenariop. 175
Chapter 11 Creating Demilitarized Zones with a Single Firewallp. 179
Looking at the Demilitarized Zone: No-Man's Landp. 179
Examing Typical DMZ Configurationsp. 180
Designing Three-Pronged Firewallsp. 182
Deploying a Three-Pronged Firewallp. 186
Building a Case for Multi-Pronged Firewallsp. 195
Chapter 12 Designing Demilitarized Zones with Multiple Firewallsp. 197
When Two Firewalls Are Better than Onep. 197
DMZs with Two Firewallsp. 200
Part IV Deploying Solutions Using Firewall Productsp. 211
Chapter 13 Using Windows as a Firewallp. 213
Firewall Functions in Windowsp. 214
Windows 98 and Windows Mep. 216
Windows NT 4.0p. 221
Windows 2000p. 224
Windows XPp. 230
Windows Server 2003p. 232
Chapter 14 Configuring Linux as a Firewallp. 233
Making Installation Choicesp. 233
Introducing iptablesp. 235
Using iptables Commandsp. 237
Simplifying Things: Firewall GUIsp. 246
Adding Proxy Functionalityp. 247
Chapter 15 Configuring Personal Firewalls: ZoneAlarm, BlackICE, and Norton Personal Firewallp. 249
Home Computers at Riskp. 250
Features of Personal Firewallsp. 253
How to Be Safe on the Internetp. 258
Personal Firewall: ZoneAlarmp. 259
Personal Firewall: BlackICEp. 269
Norton Personal Firewallp. 283
Chapter 16 Microsoft's Firewall: Internet Security and Acceleration Serverp. 295
Making Internet Access Faster and More Securep. 296
Looking under the Hood: How ISA Worksp. 297
Choosing between the Two Editionsp. 301
Preparing for Installationp. 302
Installing ISA Serverp. 305
Examining the Three Clientsp. 312
Following the Rules: The Two Typesp. 317
Letting the Good Guys Inp. 320
Creating Packet Filtersp. 322
Designing Your Network with ISA Serverp. 326
Taking the Next Stepp. 329
Chapter 17 The Champ: Check Point FireWall-1 Next Generationp. 331
FireWall-1 Featuresp. 331
FireWall-1 Componentsp. 339
FireWall-1 Next Generation Installationp. 342
FireWall-1 NG Configuration Tasksp. 347
Chapter 18 Choosing a Firewall That Meets Your Needsp. 357
How Do You Decide?p. 357
What to Compare?p. 358
What Are Some of the Choices?p. 363
Part V The Part of Tensp. 365
Chapter 19 Ten Tools You Can't Do Withoutp. 367
Sam Spadep. 368
Nmapp. 369
Netstatp. 369
TCPViewp. 370
TDIMonp. 370
FPortp. 371
Snortp. 371
Internet Scannerp. 372
Nessusp. 373
Network Monitorp. 373
Etherealp. 373
NetCatp. 374
Chapter 20 Ten Web Sites to Visitp. 375
www.sans.orgp. 375
www.cert.orgp. 376
www.infosyssec.orgp. 377 378
www.icsalabs.comp. 379
www.securityfocus.comp. 380
www.gocsi.comp. 380
www.isaserver.orgp. 381 381
Firewall Listsp. 382
Appendix Protocol Listings and Morep. 383
IP Protocol Numbersp. 383
ICMP Type Numbersp. 384
TCP and UDP Port Listingp. 384
Indexp. 393