Getting Your Network Ready

Without an Internet connection, your TA would make a pretty good paperweight. The cables kind of clutter your desktop, though, so you might want to leave them in the box.

In this section, I outline the things you need to do to get your network ready for VoIP communications. I sketch out a basic home office network and show you where your TA can be connected. I discuss settings you'll want to check out on your Internet gateway to ensure that you can connect to your VoIP service provider.

For simplicity and security, I recommend the use of an Internet gateway for connection to the Internet. However, if you do choose to connect your TA directly, without a gateway, I cover a few things you will need to do to get connected.

An Internet gateway device connects your home network to the Internet while protecting your computers from direct access by hackers. It includes features that filter out harmful traffic while allowing good traffic to reach your systems. Some gateways even offer the ability to restrict certain kinds of use by family members. These parental controls are recommended by child-safety advocates and law enforcement to protect children from online predators.

Internet gateway devices usually have one port that connects to your cable or DSL modem. This is called the WAN (wide area network) port. Traffic bound for this port must pass through your filters and controls before being allowed to reach computers on the inside.

Gateways also have one or more ports to which you connect computers on the internal network. These ports allow unrestricted access to other computers on the internal network to let you share files and printers or play network games. This activity occurs without any external indication of activity to tip off hackers. When an internal computer needs to access Internet resources, the gateway opens a connection to the Internet resource on behalf of the internal computer and acts as the go-between for the communications session.

Connecting your TA with an Internet gateway

When you connect your TA to an Internet gateway device, as shown in Figure 4.1, it will usually be assigned a network address by the gateway. When the TA attempts to connect to your VoIP service provider, it notifies the gateway that it wants to connect. The gateway opens a channel to the VoIP service provider to allow the TA to connect. This channel remains open as long as communication is taking place. Hackers see only the external address of your gateway, not the TA itself.

Figure 4.1. Your telephone adapter "all safe and sound" behind a gateway

Note

Some gateways might not be configured to assign addresses automatically. If this is the case, you might have to manually assign your TA an address that will work on your network. This topic is covered in Chapter 6.

Connecting without a gateway

Some TAs are designed to be placed outside your gateway (Figure 4.2). They connect between your network and the Internet. The D-Link DVG-1120 includes basic gateway functionality and can manage connections to internal computers on a second network port designed for this purpose.

Figure 4.2. The D-Link DVG-1120 can be used as an Internet gateway device

Tip

If you plan to connect only a single computer to one of these devices, you can do without the switch depicted in Figure 4.2. A single computer can be connected directly to the TA itself.

If you connect a TA outside an Internet gateway, it essentially becomes the gateway to your network. It will manage addressing for one or more internal computers and also manage VoIP call processing. In many ways, this type of TA is very similar to a combination TA and gateway but offers somewhat less functionality when it comes to features such as firewalls and parental controls. If these features are very important to you, you might consider a full-featured TA/gateway combo device. I discuss the selection and installation of these devices later in this chapter, in "Installing a Combination TA/Gateway."