3. Connecting to the Internet
This chapter provides
The SnapGear appliance provides secure Internet access using its robust embedded firewall. The SnapGear appliance has an IP masquerading feature, which means that users on your local network can see the outside world; however the outside world cannot see inside your local network. This shields your network from intruders and also allows you to filter packets (see Chapter 6, Firewall) to prevent unwanted traffic to/from your network.
The SnapGear appliance can connect to the Internet using an external dialup analog modem, an ISDN modem, a permanent analog modem, a cable modem or DSL link as shown in the following figure:
Figure 3.1 Internet connection
Physically connect modem device
The first step in connecting your office network to the Internet is to physically attach your SnapGear appliance to the modem device. For analog modems, attach the modem serial cable to one of the SnapGear appliance’s serial ports (i.e. COM1, COM2). For digital connections (e.g. cable, DSL), plug the cable into the Internet port.
Warning
To connect to an ISDN line, the SnapGear appliance requires an intermediate device called a Terminal Adapter (TA). A TA connects into your ISDN line and has either a serial or Ethernet interface that is connected to your SnapGear appliance. Do NOT plug an ISDN connection directly in to your SnapGear appliance.
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Connecting to the Internet
