NETWORKING FOR IDIOTS!!!!!!!!1

This section provides a basic introduction to the technologies that underlie the Internet. It was written with the novice end-user in mind and is not intended to be a comprehensive survey of all Internet-based technologies. Subsections provide a short overview of each topic. This section is a basic primer on the relevant technologies. For those who desire a deeper understanding of the concepts covered here, we include links to additional information.

What does broadband mean?

"Broadband" is the general term used to refer to high-speed network connections.  In this context, Internet connections via cable modem and Digital Subscriber Line (DSL) are frequently referred to as broadband Internet connections. "Bandwidth" is the term used to describe the relative speed of a network connection -- for example, most current dial-up modems can support a bandwidth of 56 kbps (thousand bits per second). There is no set bandwidth threshold required for a connection to be referred to as "broadband", but it is typical for connections in excess of 1 Megabit per second (Mbps) to be so named.

What is cable modem access?

A cable modem allows a single computer (or network of computers) to connect to the Internet via the cable TV network. The cable modem usually has an Ethernet LAN (Local Area Network) connection to the computer, and is capable of speeds in excess of 5 Mbps.
Typical speeds tend to be lower than the maximum, however, since cable providers turn entire neighborhoods into LANs which share the same bandwidth.  Because of this "shared-medium" topology, cable modem users may experience somewhat slower network access during periods of peak demand, and may be more susceptible to risks such as packet sniffing and unprotected windows shares than users with other types of connectivity. (See the "Computer security risks to home users" section of this document.)

What is DSL access?

Digital Subscriber Line (DSL) Internet connectivity, unlike cable modem-based service, provides the user with dedicated bandwidth. However, the maximum bandwidth available to DSL users is usually lower than the maximum cable modem rate because of differences in their respective network technologies. Also, the "dedicated bandwidth" is only dedicated between your home and the DSL provider's central office -- the providers offer little or no guarantee of bandwidth all the way across the Internet.
DSL access is not as susceptible to packet sniffing as cable modem access, but many of the other security risks we'll cover apply to both DSL and cable modem access. (See the "Computer security risks to home users" section of this document.)

How are broadband services different from traditional dial-up services?

Traditional dial-up Internet services are sometimes referred to as "dial-on-demand" services. That is, your computer only connects to the Internet when it has something to send, such as email or a request to load a web page. Once there is no more data to be sent, or after a certain amount of idle time, the computer disconnects the call. Also, in most cases each call connects to a pool of modems at the ISP, and since the modem IP addresses are dynamically assigned, your computer is usually assigned a different IP address on each call. As a result, it is more difficult (not impossible, just difficult) for an attacker to take advantage of vulnerable network services to take control of your computer.
Broadband services are referred to as "always-on" services because there is no call setup when your computer has something to send. The computer is always on the network, ready to send or receive data through its network interface card (NIC). Since the connection is always up, your computer’s IP address will change less frequently (if at all), thus making it more of a fixed target for attack.
What’s more, many broadband service providers use well-known IP addresses for home users. So while an attacker may not be able to single out your specific computer as belonging to you, they may at least be able to know that your service providers’ broadband customers are within a certain address range, thereby making your computer a more likely target than it might have been otherwise.
The table below shows a brief comparison of traditional dial-up and broadband services.

	Dial-up	Broadband
Connection type	Dial on demand	Always on
IP address	Changes on each call	Static or infrequently changing
Relative connection speed	Low	High
Remote control potential	Computer must be dialed in to control remotely	Computer is always connected, so remote control can occur anytime
ISP-provided security	Little or none	Little or none
Table 1: Comparison of Dial-up and Broadband Services

How is broadband access different from the network I use at work?

Corporate and government networks are typically protected by many layers of security, ranging from network firewalls to encryption. In addition, they usually have support staff who maintain the security and availability of these network connections.
Although your ISP is responsible for maintaining the services they provide to you, you probably won’t have dedicated staff on hand to manage and operate your home network. You are ultimately responsible for your own computers. As a result, it is up to you to take reasonable precautions to secure your computers from accidental or intentional misuse.

What is a protocol?

A protocol is a well-defined specification that allows computers to communicate across a network. In a way, protocols define the "grammar" that computers can use to "talk" to each other.

What is IP?

IP stands for "Internet Protocol". It can be thought of as the common language of computers on the Internet. There are a number of detailed descriptions of IP given elsewhere, so we won't cover it in detail in this document. However, it is important to know a few things about IP in order to understand how to secure your computer. Here we’ll cover IP addresses, static vs. dynamic addressing, NAT, and TCP and UDP Ports.