The truth, as usual, is somewhere in between. While DSL and cable modem users do face a greater risk of Internet attacks than do dial-up users, the main difference is one of magnitude. And using a modem to connect a desktop system directly to the Internet, bypassing your organization's firewall, may expose your internal network to attacks. DSL and cable modem users are already facing attacks because the address ranges used by suppliers of these full-time connections are known. If past history is any guide, attacks that target systems with always-on connections will increase.
Any system connected to the Internet needs protection.
For desktop systems, software or hardware firewalls make sense, whether you use a modem or a full-time link. On Point PPP defines a method for encapsulating and transporting other network protocols. PPP supports IP and other protocols, such as NetWare and AppleTalk. PPP is primarily used to set up connections over serial lines connected by modems. The protocol handles authentication, negotiates compression, monitors link reliability, and also handles breaking down a connection.