Chapter 10: Connecting Your Network to the Internet

So you decided to connect your network to the Internet. All you have to do is run to the local computer discount store, buy a cable modem, and plug it in, right? Wrong. Unfortunately, connecting to the Internet involves more than just installing a modem. For starters, you have to make sure that a modem is the right way to connect-other methods are faster but more expensive. Then you have to select and configure the software you use to access the Internet. Finally, you have to lie awake at night worrying whether hackers are breaking into your network via its Internet connection.

Connecting to the Internet

Connecting to the Internet isn't free. For starters, you have to purchase the computer equipment necessary to make the connection. Then you have to obtain a connection from an Internet Service Provider, or ISP. The ISP charges you a monthly fee that depends on the speed and capacity of the connection.

The following sections describe the most commonly used methods of connecting network users to the Internet.

Connecting with cable or DSL

For small and home offices, the two most popular methods of connecting to the Internet are cable and DSL. Cable and DSL connections are often called broadband connections, for technical reasons you don't really want to know.

Cable Internet access works over the same cable that brings 40 billion TV channels into your home, whereas DSL is a digital phone service that works over a standard phone line. Both offer three major advantages over normal dialup connections:

• Cable and DSL are much faster than dialup connections.

  A cable connection can be anywhere from 10 to 200 times faster than a dialup connection, depending on the service you get. And the speed of a DSL line is comparable to cable. (Although DSL is a dedicated connection, cable connections are shared among several subscribers. The speed of a cable connection may slow down when several subscribers use the connection simultaneously.)

• With cable and DSL, you're always connected to the Internet.

  You don't have to connect and disconnect each time you want to go online. No more waiting for the modem to dial your service provider and listening to the annoying modem shriek as it attempts to establish a connection.

• Cable and DSL don't tie up a phone line while you're online.

  With cable, your Internet connection works over TV cables rather than over phone cables. With DSL, the phone company installs a separate phone line for the DSL service, so your regular phone line isn't affected.

Unfortunately, there's no such thing as a free lunch, and the high-speed, always-on connections offered by cable and DSL don't come without a price. For starters, you can expect to pay a higher monthly access fee for cable or DSL. In most areas of the United States, cable runs about $50 per month for residential users; business users can expect to pay more, especially if more than one user will be connected to the Internet via the cable.

The cost for DSL service depends on the access speed you choose. In some areas, residential users can get a relatively slow DSL connection for as little as $30 per month. For higher access speeds or for business users, DSL can cost substantially more.

Cable and DSL access aren't available everywhere. If you live in an area where cable or DSL isn't available, you can still get high-speed Internet access by using a satellite hookup. With satellite access, you still need a modem and a phone line to send data from your computer to the Internet. The satellite is used only to receive data from the Internet. Still, a satellite setup like this is much faster than a modem-only connection.

Connecting with high-speed private lines: T1 and T3

If your network is large and high-speed Internet access is a high priority, contact your local phone company (or companies) about installing a dedicated high-speed digital line. These lines can cost you plenty (on the order of hundreds of dollars per month), so they're best suited for large networks in which 20 or more users are accessing the Internet simultaneously.

A T1 line has a connection speed of up to 1.544 Mbps. A T3 line is faster yet: It transmits data at an amazing 44.184 Mbps. Of course, T3 lines are also considerably more expensive than T1 lines.

If you don't have enough users to justify the expense of an entire T1 or T3 line, you can lease just a portion of the line. With a fractional T1 line, you can get connections with speeds of 128 Kbps to 768 Kbps, and with a fractional T3 line, you can choose speeds ranging from 4.6 Mbps to 32 Mbps.

Setting up a T1 or T3 connection to the Internet is stuff best left to professionals. Getting this type of connection to work is far more complicated than setting up a basic LAN.

Tip 

You may be wondering whether T1 or T3 lines are really any faster than cable or DSL connections. After all, T1 runs at 1.544 Mbps and T3 runs at 44.184 Mbps, and cable and DSL claim to run at comparable speeds. But there are many differences that justify the substantial extra cost of a T1 or T3 line. In particular, a T1 or T3 line is a dedicated line-not shared by any other users. T1 and T3 are higher-quality connections, so you actually get the 1.544 or 44.184 connection speeds. In contrast, both cable and DSL connections usually run at substantially less than their advertised maximum speeds because of poor-quality connections.

Sharing an Internet connection

After you choose a method to connect to the Internet, you can turn your attention to setting up the connection so that more than one user on your network can share it. The best way to do that is by using a separate device called a router. An inexpensive router for a small network can be had for under $100. Routers suitable for larger networks will, naturally, cost a bit more.

Because all communications between your network and the Internet must go through the router, the router is a natural place to provide the security measures necessary to keep your network safe from the many perils of the Internet. As a result, a router used for Internet connections often doubles as a firewall, as described in the section "Using a firewall," later in this chapter.