Chapter 1: The Internet and Security

1.1 The history of the Internet

1.1.1 The Internet

Back in 1866, the Wild West was "the future utopia" to Americans who were already in what was originally supposed to be "the land of opportunity." Civil War, reconstruction, and corruption in the White House were the current headlines of the day. Thus, eyes turned to the West for opportunity and new beginnings. The Wild West was supposed to be a place where everyone could go for cheap land, free gold, and a good beach (and eventually surfing, if they made it to the coast). The Wild West was often not this ideal, as demonstrated by the word "Wild." Many used it and abused it for the purpose of pillaging, robbing, lawlessness, and bordellos. It is not so different with today's Internet. The Internet is supposed to be a network that links thousands, millions, or even billions of computers together in order to send and receive data in perfect tranquility. First, the Internet is not a single network and, as you may have guessed, it is not always safe. The Internet is changing by the day, by the hour, by the minute, and has changed the face of technology and business both in just under three decades. The Internet is more than 27 years old. The WWW (World Wide Web, e.g., http://www.lookatmywebpage.com/^[1]) is actually less than 10 years old. Before the WWW, there was WORM, the first of which burrowed through the Internet in 1988. As you can see, the Internet has been around for quite some time. Web sites developed more recently. The Internet is not a single agency, a network, or a company. It is a collection of networks and authorities. Following are a few dates (and decades) to tell you how it became as it is today.

In 1858, a telegram of 98 words from Queen Victoria to President James Buchanan of the United States opened a new era in global communication. The queen's message of congratulation took 16 hours to transmit through the new transatlantic telegraph cable. The president then sent a reply of 143 words back to the queen. Normally, without the cable, a dispatch in one direction would have taken perhaps 12 days by the speediest combination of inland telegraph and fast steamer.

Just a bit more than 100 years later, we see the creation of a new medium of communication, based on the same basic technology of the telegraph, electrons, and wires^[2]. Starting in the early 1960s, we see the creation of ARPANET, the beginning of the Vietnam War, and the rise of bell-bottoms and ring pops. A lot happened in the 1960s that has helped develop the Internet into the Ebays, Amazons, AOLs, and hotornots that we know, love, and sometimes hate.

July, 1961: At MIT, Leonard Kleinrock (i.e., ubernerd) published the first paper on the packet switching theory. Kleinrock convinced his peers that communication using packets, rather than circuits, was not only feasible but also practical. Experiments followed, but only circuit type connections were tested. Thus, the results of these experiments demonstrated the need for packet communications.

August, 1962: Memos written by J. C. R. Licklider of MIT discussed the possibility and use of networked computers. The concept was titled, "The Galactic Network," by Licklider. Yes, he came up with this term before Star Trek was on the air. Licklider envisioned a globally interconnected set of computers through which everyone could access data and programs, no matter where they were physically. He became the first head of the computer research program at DARPA.

Mid-1960s: People began writing all types of papers on the subject of networks. One of the first papers on the ARPANET^[3] was published by Lawrence G. Roberts^[4]. Also at this time were papers on packet switching. One such paper was written by a good gentleman known as Donald Davies. Donald is the English inventor of packet switching. He theorized at the British National Physical Laboratory (NPL) about building a network of computers to test his packet switching concepts. At about the same time, 1964 (besides the Beatles and James Bond), Paul Baran and others at the RAND group had written a paper on packet switching networks for secure voice in the military. With all of these papers being floated around, it happened that the work at MIT^[5] (1961 1967), the work at the RAND corporation (1962 1965) and the work at the NPL (1964 1967) had occurred all at the same time and without any of the researchers knowing about the others' work. The word packet was adopted from the work at the NPL. A packet is a unit of data that is routed between a network source and a network destination on any network.

August, 1968: An RFQ (Request for Quote) was released by DARPA^[6] for the development of the key components for the ARPANET. The RFQ included the definition and creation of a device known as the IMP^[7]. The IMP's job was to manage the packets and provide an interface to the computer at each site. A group headed by Frank Heart at Bolt Beranek and Newman (BBN) won the job in 1968. The team at BBN worked on the IMP with Bob Kahn, thus playing a major role in the overall ARPANET architectural design. The Network Measurement Center at UCLA was selected to be the first device (or node) on the ARPANET.

1969: ARPANET was brought to fruition when BBN installed the first IMP^[8] at UCLA and the first computer was connected. Another computer at Stanford Research Institute (SRI) provided a second node. One month later, the first host-to-host message was sent across the network. Two more nodes were added at UC Santa Barbara and University of Utah. Finally, by the end of 1969, four host computers were connected together into the initial ARPANET and the future Internet was born. Also, in 1969, a movie was released known as "Colossus: The Forbin Project." An American supercomputer, Colossus, and its Russian counterpart, Guardian, got together to rule the world. This movie was filmed at the Lawrence Hall of Science, Berkeley, California. This great movie, years ahead of its time, showed two computers that became "aware" or "alive" and then decided to connect themselves together aka a "network." Some concepts you can find in that movie are:

• Computer virus

• Network

• Artificial intelligence

• Voice activation response

Many of the technologies that we have today were alluded to in that science fiction movie.

Back to the history. At this point, we now have four computers on the ARPANET. A team of engineers/researchers/nerds get together to work on the software that will enable the computers to communicate. At UCLA, Vint Cerf, Steve Crocker, and Jon Postel work with Leonard Kleinrock^[9] to create the software. On April 7, Crocker sends around a memo entitled "Request for Comments (RFC)." This is the first of many future RFCs that document the design of the ARPANET and the Internet. The team called itself the "Network Working Group (aka RFC 10)." The team took it upon itself to develop something called a "protocol." This first network protocol was a collection of programs that came to be known as NCP (Network Control Protocol). From 1970 to 1973, several events occurred in our history:

1. Bob Metcalfe^[10] built a network interface between the MIT IMP and a PDP-6 to the ARPANET. Metcalfe asks to build another network interface for Xerox PARC's PDP-10^[11].

2. The Network Working Group^[12] completes the Telnet protocol and makes progress on the file transfer protocol (FTP) standard.

3. Kahn and Cerf design a net-to-net connection protocol. Cerf now leads the International Network Working Group. In September 1973, the two give their first paper on the new Transmission Control Protocol (TCP) at a meeting at the University of Sussex in England.

4. Ray Tomlinson,^[13] a programmer at Bolt Beranek and Newman, invented e-mail in late 1971. Tomlinson created e-mail to send messages over a network to fellow programmers.

The 1970s: Low riders and the Rolling Stones. Ugly pants and Robert Redford.

1973: We were at a critical juncture. NCP was the dominant protocol but it did not have the ability to address networks (or computers) further down the network than a destination IMP on the ARPANET. NCP needed to be updated or replaced. Here was the problem: If a packet was lost, then the application using the network may crash. For the most part, NCP had no end-end host error control and since the ARPANET was to be the only network around, it would need to be so reliable that no error control would be required. As a result, Cerf (pronounced "serf") and Kahn developed a new protocol. This protocol would eventually be called the Transmission Control Protocol/Internet Protocol (TCP/IP). The TCP/IP protocol was the glue that the future Internet needed. This single protocol was able to solve many different issues and problems:

1. TCP/IP was able to stand on its own within each distinct network. As a result, no internal changes were required to "connect" the network together.

2. Communications within the network would be on a best effort basis. If a packet didn't make it to the final destination, it would shortly be retransmitted from the source.

3. Special boxes would be used to connect these disparate networks; these would later be called gateways and routers.

4. There would be no global control at the operations level.

5. Defined Gateway functions would forward packets as needed to the correct network.

6. Checksums were used and packets could be "fragmented"^[14] or sent out of order and, at the destination, be put back into the correct order.

It is amazing how scalable the original TCP/IP protocol was. Today we call the protocol IP(v4), or version 4 of the IP protocol. The original model that Cerf and Kahn put together was designed to accommodate the requirement of the ARPANET. The idea of thousands of networks was not really on their mind. The IP protocol uses a 32-bit base. If you take off of these bits and factor out the numbers available you have about 4 billion possible addresses (2³²) bits. The original idea was to use a 32-bit IP address and cut it into chunks. The network used the first 8 bits and the remainder (24) was to be used by the hosts (or computers). Take a look at 2⁸ bits, you have 256 possible combinations that you could use for networks. In the 1970s, that was plenty, but today we are out of network numbers (We will discuss TCP/ IP addressing in a later chapter, and a bit on IP(v6). We will not discuss UDP, ever. Well all correct, maybe a bit later on). In the 1970s, the addressing scheme was genius. I don't know if Cerf and Kahn were lucky or brilliant, but in any case, we benefited from their design. Thanks, Mr. Cerf and Mr. Kahn!

The early implementations of TCP were done for large time-sharing^[15] systems such as Tenex and TOPS 20. Good old TOPS 20 was software that ran on a system known as the KL-10 from Digital Equipment. The KL-10 was a 36-bit "mainframe" from DEC. When desktop computers first appeared, it was thought by some that TCP was too big to run on a personal computer. This dude named David Clark (as far as I know he was not part of the Dave Clark 5) and a research group from MIT set out to show that a compact and simple implementation of TCP was possible. The first implementation was for the Xerox Alto and the IBM PC.

From 1974 to 1980, several events occurred in the history of the Internet:

• By 1974, daily traffic on the ARPANET exceeds 3 million packets and the Ethernet was demonstrated at Xerox PARC's center.

• In 1975, the ARPANET geographical map shows 61 nodes.

• In 1976, the packet satellite project went into use. SATNET, Atlantic packet Satellite network, was born. This network linked the United States with Europe.

• In 1977, Steve Wozniak and Steve Jobs announce the Apple II computer. Also introduced is the Tandy TRS-80. These off-the-shelf machines create the consumer and small business markets for computers.

• In 1978, Continuing work on TCP/IP, Vint Cerf at DARPA expands the vision of the Internet, forming an International Cooperation Board chaired by Peter Kirstein of University College London.

• In 1979, Newsgroups are created, aka USENET.

The 1980s: This decade saw a string of important developments in ARPANET's journey to becoming the all-seeing, all-knowing, all-selling, and all-buying Internet. The decade also had something to do with disco, but who cares about that. It died anyway.

1980: TCP/IP was adopted as a defense standard. This enabled the defense complex to begin sharing in the DARPA Internet technology base. By 1983, ARPANET was being used by a significant number of defense research and development and operational organizations. As of January 1, 1983, the ARPANET moved over to a single protocol, TCP/IP. All hosts converted simultaneously. Over several years, the transition was carefully planned^[16] within the community before it actually took place. The year 1983 saw another critical point for the Internet: DNS was invented. Here is the issue. Every computer had an address, for example, 192.9.200.123. We could keep track of these numbers if we had about 30 to 40 computers. But what if we had thousands of computers, how would we (humans) keep track of all those numbers? Numbering the Internet hosts and keeping tabs on the host names simply failed to scale with the growth of the Internet. In November 1983, Jon Postel and Paul Mockapetris of USC/ISI and Craig Partridge of BBN developed the Domain Name System (DNS). The DNS system provided an on-line mechanism to track the names of computers in relation to their IP address. Previously, each computer needed to maintain its own list. So if you added a computer to the network, you would need to edit each list on each computer. In the case of DNS, all you need to do is edit the list at one place.

1984: The DNS system was introduced across the Internet with domain suffixes. You have seen these before: .gov, .mil, .edu, .org, .net, and .com. The Internet was starting to mature. By 1985, the Internet was already well established as a technology supporting a broad community of researchers and developers and was beginning to be used by other communities for daily computer communications. Electronic mail (via SMTP^[17]) was being used broadly across several communities, often with different systems, but interconnection between different mail systems was demonstrating the utility of broad based electronic communications between people.

1985: By the end of this year, the number of hosts on the Internet (TCP/IP interconnected networks) had reached about 2,000. Also, at this time there were several RFCs created that described a concept known as subneting. This process involved a mask number being placed along with an IP address. This, in effect, would divide an IP network into several networks^[18]. Between the beginning of 1986 and the end of 1987, the number of networks grew from 2,000 to nearly 30,000. TCP/IP^[19] was now available on workstations and PCs such as the Compaq portable computer. Ethernet^[20] was starting to grow and become available across college campuses. In 1986, the U.S. National Science Foundation (NSF) initiated the development of the NSFNET, which provided a major backbone communication service for the Internet.

As we look into the 1980s, the question comes up about ... not Boy George and Duran Duran, but something more comical: Al Gore and the Internet. There is no explanation better than the one from Cerf and Kahn:

As a Senator in the 1980s, Gore urged government agencies to consolidate what at the time were several dozen different and unconnected networks into an "Interagency Network." Working in a bi-partisan manner with officials in Ronald Reagan and George Bush's administrations, Gore secured the passage of the High Performance Computing and Communications Act in 1991. This "Gore Act" supported the National Research and Education Network (NREN) initiative that became one of the major vehicles for the spread of the Internet beyond the field of computer science. http://www.isoc.org/internet-history/gore.shtml

A great deal of support for the Internet community has come from the U.S. federal government, since the Internet was originally part of a federally funded research program and, subsequently, has become a major part of the U.S. research infrastructure. Throughout its history, the Internet has provided a platform for collaboration and communication. The Internet Activities Board (IAB) was created in 1983 to guide the evolution of the TCP/IP Protocol Suite and to provide research advice to the Internet community. During its short existence, the IAB has reorganized many times and now has two primary components: the Internet Engineering Task Force (IETF) and the Internet Research Task Force. The IETF^[21] has responsibility for further evolution of the TCP/IP protocol suite and its standardization.

As we continue down the road of history we find The Morris WORM. In 1988, this worm burrowed into the Internet and into 6,000 of the 60,000 hosts now on the network at this time. This is the first worm experience and DARPA forms the Computer Emergency Response Team (CERT ^[22]) to deal with future such incidents^[23].

1989: The number of hosts has increased to 160,000. Also, we see the advent of commercial e-mail relays. Network speeds are up to 45Mbps and 100Mbps is on the horizon based on FDDI. Now we hear the first rumblings of the "Web." In Switzerland, at CERN^[24], Tim Berners-Lee addresses the issue of the constant change in the currency of information and the turnover of people on projects. Mr. Berners-Lee^[25] proposed something called "Hypertext" which is a system that will run across distributed systems on different operating systems.

The 1990s: The Internet, as we know it, is born. Millions of web sites appear and try to sell you everything you ever wanted, including the things you wouldn't have bought unless they had appeared right there on your monitor in your living room while you were drinking coffee and listening to the news. Oh, and Clinton gets elected. Twice.

1990 to 1992: We see a number of changes and enhancements to the Internet:

• The number of networks exceeds 7,500 and the number of computers connected grows beyond million.

• Over 100 countries are now connected with over 600,000 computers.

• The Web is born. SLAC, the Stanford Linear Accelerator Center in California, becomes the first web server in the United States. It serves the contents of an existing, large database of abstracts of physics papers.

In 1993: We saw some of these events:

• The U.S. White House comes on-line (http://www.whitehouse.gov/).

• RFC 1437: The Extension of MIME Content-Types to a new medium.

• RFC 1438: IETF Statements of Boredom (SOBs).

• Marc Andreesen and NCSA and the University of Illinois develop a graphical user interface to the WWW, called "Mosaic for X."

No major changes were made to the physical network in 1994, except for its significant growth. Other events from this year include:

• Pizza Hut offers pizza ordering on its web page.

• Shopping malls arrive on the Internet.

• Internet traffic passes 10 trillion bytes/month.

• RFC 1607: A View from the 21st Century (this is another great RFC check it out at http://info.internet.isi.edu/in-notes/rfc/files/rfc1607.txt).

• First Virtual, the first cyberpunk, opens.

• The URI is defined http://info.internet.isi.edu/in-notes/rfc/files/rfc1630.txt.

• The URL is defined http://info.internet.isi.edu/in-notes/rfc/files/rfc1738.txt.

On October 24, 1995, the Federal Networking Council (FNC) unanimously passed a resolution defining the term "Internet." A resolution was drafted that stated the following:

The term "Internet" refers to the global information system that:

1. is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/ follow-ons;

2. is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP-compatible protocols; and

3. provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein.

1995: We also saw these events:

• The National Science Foundation announced that as of April 30, 1995 it would no longer allow direct access to the NSF backbone. The National Science Foundation contracted with four companies that would be providers of access to the NSF backbone (Merit). These companies would then sell connections to groups, organizations, and companies.

• A $50 annual fee is imposed on domains excluding .edu and .gov domains, which are still funded by the National Science Foundation.

• WWW surpasses ftp-data in March as the service with greatest traffic.

• RFC 1825, Security Architecture for the Internet Protocol, http://info.internet.isi.edu/in-notes/rfc/files/rfc1825.txt

• RFC 1882 you need to see this one. http://info.internet.isi.edu/in-notes/rfc/files/rfc1882.txt

The Internet has changed much since it came into existence. This ubiquitous network was designed before LANs were even thought of and yet, today it can accommodate a massive amount of traffic. From 1996 to 2001, the Internet continued to grow. New applications and features were developed and implemented. The hot topic became security. In fact, from 1996 to today we have seen these events:

• U.S. Communications Decency Act (CDA) becomes law in order to prohibit distribution of indecent materials.

• Various ISPs suffer extended service outages, bringing into question whether they will be able to handle the growing number of users.

• A malicious program is released on USENET, wiping out more than 25,000 messages.

• Human error at Network Solutions causes the DNS table for .com and .net domains to become corrupted.

• Viruses such as Melissa, ExploreZip, and Love Letter.

• Stolen identities, denial of service attacks, child pornography, and the famous dot-com crash of 2001. And the very sad death of the sock puppet. Why? Because pets can't buy (or use a credit card for that matter). The fact that pets can't drive is a moot point.

1.1.2 The Ethernet

Why pick on the Ethernet for its own section and history? Because many of the examples we will be discussing are on the Ethernet. The Ethernet is a system for connecting computers within a building (or your house) using dedicated hardware and software running from machine to machine.

Xerox's Palo Alto Research Center (PARC) is where some of the first personal computers were created. Robert Metcalfe was a member of the research staff and was asked to build a networking system for PARC's computers. The motivation for the computer network was that Xerox was also building the world's first laser printer and wanted all of the PARC's computers to be able to print with this printer. Mr. Metcalfe had two challenges:

1. The network had to be fast enough to drive the new laser printer.

2. The network needed to connect hundreds of computers within the same building.

There are several disputing stories about when the Ethernet was really invented. For us it really does not matter. If you want a date, use the date from Robert Metcalfe. He said, "gradually over a period of several years." In about 1979, Metcalfe left Xerox to evangelize the use of personal computers and local area networks. Metcalfe was able to sell Digital Equipment, Intel, and Xerox Corporations on this concept and get them to work together to promote Ethernet as a standard. In fact, one of the original connectors used was called a DIX connector. Get it? Digital, Intel, Xerox.