Creating and Implementing Virtual Private Networks

Creating and Implementing Virtual Private Networks

by Casey Wilson, Peter Doak

Teaches the theory, implementation, guidelines, and security aspects of VPNs. Divulges the details behind encryption tools, government restrictions, firewall architectures, client/server technology, security tools, cryptography, and much more. Covers firewalls and how to use them with Cisco routers, proxy servers, TCP/IP, FTP, and more. Covers VPN architecture,…  See more details below


Teaches the theory, implementation, guidelines, and security aspects of VPNs. Divulges the details behind encryption tools, government restrictions, firewall architectures, client/server technology, security tools, cryptography, and much more. Covers firewalls and how to use them with Cisco routers, proxy servers, TCP/IP, FTP, and more. Covers VPN architecture, advantages and disadvantages of using a VPN, and emerging technologies that may harm VPNs in the future. Provides real-life examples of installing, maintaining, and troubleshooting a VPN.

Covers the best practices and implementation of Virtual Private Networks (VPNs) —currently no other book provides actual how-to information. The only documented resource on common hacker attacks against networks—plus, it provides the dos and don'ts on how to protect against them. Written for the Unix, Windows, and NT platforms. Provides handy resources and charts to evaluate data trends and perform valuable cost-benefit analysis—the first step in implementing a VPN.

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Editorial Reviews

A guide for network administrators, MIS managers, information technologists, and technicians with experience in networking. Shows how to create and maintain a Virtual Private Network (VPN) that allows companies to send data across the Internet through an encrypted "tunnel." Screenshots and step-by-step examples are used to further explain concepts. Wilson has researched design and installation of data interfaces. Doak is a professor of electronics and computer systems technology at the College of the Mainland in Texas. Annotation c. Book News, Inc., Portland, OR (

Product Details

Coriolis Group
Publication date:
Product dimensions:
7.39(w) x 9.20(h) x 1.60(d)

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Chapter 1: VPN, What's It All About?

The shortest way to define Virtual Private Networking is to say that it is a scheme for using the Internet as a backbone for computer networks. On the surface that doesn't seem like much, but when you dig in, it offers tremendous potential. Some enterprises could save tens of thousands of dollars over what they are now paying for leased lines for existing networks. But use of VPN doesn't require the sites to be located around the world, or across the country, or on the other side of the state-they could be, but they could just as easily be on the other side of Your Town, U.S.A. In fact, the tools and techniques that make up VPN technology could be applied to a Local Area Network (LAN) right in your building.


For nearly a decade, the Internet has been reasonably calm-a period almost of catching its breath, getting its second wind. The only real significant change has been in the number of users coming aboard. For the past couple of years, the tide has been welling up, gathering energy. It is about to sweep in and it is bringing Virtual Private Networking with it.

1866-A Peek At The Beginning

Networking took a tiny step forward way back in 1866, when the first cable-2,700 miles long-was strung across the Atlantic Ocean between Ireland and Newfoundland. For the intrepid pioneers of communications, the cable meant that instantaneous messages could be sent between continents for the first time. Owing to the success of that daring venture, more cables were strung and the information age began.

Well, sort of. The only power available for the telegraph systems was from batteries-the invention of a power stationwould lag a few years. The data format was based on a variation of Morse Code, combinations of marks and spaces representing characters similar to the series of dots and dashes devised by Samuel Morse.

Telegraph operators translated messages into holes punched into a streaming paper tape according to a system devised by Sir Charles Wheatstone. The paper tapes were then passed into a telegraph transmitter that sent the information across the cable at the speed of light.

Well, sort of. The electrical pulses traveled at the speed of light, but the data rate was only 100 words per minute. Teleprinters, also known as teletypewriters or sometimes just teletypes, wouldn't come around until the turn of the century-the typewriter had to be invented first.

Cable communications continued unrivaled for 36 years, until a young inventor named Marconi sent his first transatlantic wireless message from Nova Scotia to England. That event shifted the information age into a higher gear.

Well, sort of. Weather had a considerable influence on wireless transmission. The equipment was all handmade and very expensive. Most people looked on it as gadgetry.

1880- Hollerith And The Tabulating Machine

Between the laying of the cable and Marconi inventing the wireless, an American mathematician named Herman Hollerith was busy inventing a tabulating machine. Charged with compiling the census of 1890, Hollerith developed a machine that would read holes punched in a card. The machine compiled information, depending on the settings of various switches.

Hollerith didn't invent the first computer. The abacus predated it by centuries. What he did do was invent a machine that, after programming the switches to produce the desired information, merely required the operators to turn a crank. In fact, computers were people defined by a job description.

1945 - ENIAC

Communications via cable and wireless had grown from transatlantic to intercontinental.

It was also in 1945 that engineers and physicists stuffed almost 20,000 vacuum tubes, 1,500 mechanical relays, and hundreds of thousands of resistors, capacitors, and inductors into various cabinets in a 30- by 50-foot room at the University of Pennsylvania's Moore School of Electrical Engineering. Lashed together with miles of copper wire bonded together with hundreds of pounds of solder, the final construct was named the Electronic Numerical Integrator and Computer (ENIAC).

Hidden away from the public, ENIAC was a U.S. government top-secret research tool. Initially used to calculate ballistic trajectories of artillery rounds, ENIAC could do in 30 seconds what consumed 20 hours of a trained mathematician's time using the most modern calculator of that day.

In 1946, on the heels of its brilliant success, ENIAC gave way to the Universal Automatic Computer (UNIVAC). The entrepreneurs were Dr. J. W Mauchly and a university graduate student, J. P. Eckert. These two, principals in ENIAC, had a vision that they could do better. Their first customer was none other than the Census Bureau, which fronted the UNIVAC enterprise with $300,000 in 1946.

Mauchly and Eckert were much too optimistic. Basic research consumed double the estimated time on the calendar. Actual work on the contract was delayed into 1948; the government refused to allot more funds. By the time census takers were on the street in 1950, Mauchly and Eckert were considering bankruptcy.

1951-Enter Remington Rand

The corporate visionaries of the electric shaver company took a gamble and by April 1951, the first UNIVAC arrived on the doorstep of the Census Bureau. It cost almost a million dollars to deliver and the government refused to pick up the tab for the overrun, sticking to the $400,000 cap in the original contract.

UNIVAC was a technical marvel. The number of vacuum tubes was cut by more than a third. The system was packaged in much smaller, even attractive, cabinets. Remember Hermann Hollerith, the guy who made punched cards so popular with the Census Bureau? His 80 column cards could be read directly into the UNIVAC. Better still, the information from the cards could be transferred to magnetic tape, resulting in an even higher computation speed. Scientists and engineers had thought ENIAC's I KHz clock rate an astounding feat. Imagine their delight when UNIVAC rocketed along at a blistering 2 MHz.

In 1952, UNIVAC was used to predict the election of Dwight D. Eisenhower to the presidency of the United States. journalists across the country shunned UNIVAC's output; some said the race was too close to call, but most of them were just reluctant to have a machine show them up. After the election results were tallied, the accuracy of the prediction stunned the political pundits.

The word "computer" was gradually removed from job descriptions and the label stuck on machines. IBM-Big Blue-joined in, and an industry was born. No one then could conceive what the next short decades would bring.

1957-ARPA Is Born

Bill Gates was two years old when the Union of Soviet Socialist Republics launched Sputnik. Reacting to the Soviet initiative in getting into space and the implied missile capabilities, President Eisenhower launched the Advanced Research Projects Agency (ARPA). Its mission was simple: Bring the United States back into the lead in military science and technology. The green flag was dropped on the space race.

More than the mundane job of calculating trajectories of artillery rounds, computers were being tasked with aiming ballistic missiles-delivery systems for doomsday weapons. Orbital and suborbital dynamics were the meat of a geek's vocabulary. Wide-bed, 132-column printers devoured cartons of z-fold paper every hour.

More and more government facilities were being equipped with computers. Universities began installing them. Data was being exchanged between government sites and the universities. Most of it went by sneaker net; armed couriers carried the classified stuff over the longer distances where U.S. Mail couldn't be trusted.

Small groups of eclectics were figuring out how to link computers together to share information and the information age was getting ready to shift gears-again.

1962-ARPANET Goes Into Operation

Fearing that a nuclear attack on the United States might disrupt vital communications links, the Air Force commissioned the Rand Corporation to conduct a survivability study. The problem, posed in 1962, was how to establish a decentralized network so that if one site or path was demolished, command and control of nuclear bombers and missiles would continue.

Among the several alternatives was the idea of packet switching, breaking the data down into chunks at the originating computer and sending the data over existing telephone lines or via radio. The packets, each containing a discrete address and part of the final message, would be reassembled by the destination computer. If the communications link between sender and destination was disrupted, the router would select a different path. If a packet was corrupted or lost, the receiver would shoot a message back to the originator to resend it. Retransmitting a packet meant saving time over putting the entire message out again.

In 1968, ARPA awarded a contract to Bolt, Beranek, and Newman (BBN) to link four computers: SRI at Stanford, the University of California at Los Angeles and at Santa Barbara, and the University of Utah. Most of the early time was spent debugging crashes. Eventually, the early pioneers worked it out and developed the first significant protocol, called Network Control Protocol (NCP). ARPANET went into operation at 56Kbps, ostensibly as a research resource. Only a few knew the real reason.

The following year, Neil Armstrong and "Buzz" Aldrin landed on the moon. The computer they carried in the Lunar Excursion Module (LEM) plagued them on descent to the moon's surface with nearly constant alarms warning of executive overloads. It barely had enough power to perform the myriad tasks required of it.

1972-ARPA Changes Names

Several events occurred in 1972. The ARPA was shifted to the U.S. Defense Department and promptly renamed DARPA. The number of host computers increased to 24. The most significant event was triggered by Ray Tomlinson of BBN; he stuck an C-sign into an address and created email...

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