Building Internet Firewalls, 2nd Edition

Chapter 18. Remote Access to Hosts

Sometimes you want to use a network to run programs on a computer other than the one you’re sitting in front of. You might want to run a program on a much faster computer, a computer with a hardware device you don’t have (a CD writer, say), or a computer that runs an operating system you don’t like enough to have on your desk but that has some important piece of software. You might also need to administer computers that it’s inconvenient or impossible to get to physically.

You can do this a number of ways. For instance, if the remote computer supports terminals, you can connect to it over the network as if you were connecting to it via a terminal. You may also be able to send a single command to the remote computer for it to execute (remote execution). Finally, you may be able to get a connection that includes graphics. This chapter discusses the protocols used for these various kinds of connections.

Microsoft’s Remote Access Service (RAS) provides remote access to a network, not to an individual host, and is not discussed in this chapter; instead, it is discussed in Chapter 14, along with other protocols used for connecting networks, including PPP and PPTP.

Terminal Access (Telnet)

Telnet allows a user to remotely access a command shell on another computer. Telnet is supported by most platforms on the Internet, including not only Unix and Windows NT,^[1] but even some MS-DOS and Microsoft Windows systems (which provide access to a DOS shell via a ...