Chapter 3: The Internet and TCP/IP 137
95. What type of services or resources does the Internet provide?
One of the main attractions of the Internet is the services and resources that are avail-
able from it. Some of the services include e-mail, remote logins, file transfers, network
news—an electronic forum that consists of special interest groups and discussions (there
are currently over 35,000 network news groups that cover a very wide and diverse number
of topics), search tools or “engines” that allow a user to locate specific information based
on user input, communication resources such as Instant Messaging and Internet Relay
Chat (IRC), interactive games, and web browsers that enable you to view resources that
have been formatted as hypertext files. There is streaming audio and video, which enable
users to listen to audio recordings or view videos in real-time. There are also programs
that enable two-way interactive videoconferencing to take place via the Internet. Through
these services users can acquire information about nearly anything.
There are also several high-profile Internet services or resources available. These
include electronic commerce (e-commerce), Voice Over IP (VoIP), and Virtual Private
Networks (VPNs). E-commerce involves using the Internet for credit card purchases of
items such as automobiles, airline tickets, computer-related products, and books; VOIP
enables users to place telephone calls across the Internet; and VPNs enable organizations
to establish private interconnected corporate LANs using the Internet (see Chapter 7).
96. With all of these different services and resources available over the Internet, the
issue of security emerges. How secure is the Internet?
Internet security is undoubtedly of paramount concern for users. Unfortunately, the
TCP/IP protocol suite was not initially designed with security in mind. This was not an
oversight on the part of the original designers of TCP/IP. Remember: TCP/IP was initially
developed to serve the research and academic communities to facilitate the exchange of
research and scholarly activities. Inherent in this academic endeavor was a presumption of
trust and honesty. Also, many of the compromises of TCP/IP protocols today were not
anticipated by the TCP/IP designers 20 years ago.
The first major security breach of the Internet occurred on November 2–3, 1988, when
a student exploited a security “hole” in the Simple Mail Transfer Protocol (SMTP). Now
known as the “Worm incident,” many of the computers connected to NSFNET at that time
were affected and rendered useless. Since then, there have been many attempts (some suc-
cessful, some not) to exploit known weaknesses in other TCP/IP protocols, including
denial of service attacks (see Chapter 16) as well as e-mail viruses. There also is no short-
age to the number of individuals who have nothing better to do than search for creative
ways to compromise a system.
In response to these attacks, several approaches are available. The easiest thing to do is
not connect a system or network containing critical data to the Internet. A second strategy
is to encrypt sensitive data prior to transmission across the network. A third approach is to
install filters on routers that either deny or permit certain traffic to enter your network. Alter-
natively, special-purpose firewall devices that serve as buffers can also be installed between
your network and the outside world. On the protocol front, there is Secure HTTP (https) for
protecting web transactions, e-mail security is available via Secure MIME (S/MIME) and
Pretty Good Privacy (PGP), and several protocols have been developed to help secure

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