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The most aggravating thing about UNIX is that it has a million flavors. On the other hand, the best thing about UNIX is that it has a million flavors. Lots and lots of network innovations have come out of the UNIX melting pot—the Internet itself probably owes its existence to UNIX-based network inventions. Of course, TCP/IP itself grew up on UNIX computers; therefore, many TCP/IP concepts and commands from UNIX are extremely applicable to other operating systems, notably Windows NT. Even if you have no UNIX in your environment, you still might want to skim this chapter, because you probably have TCP/IP. This hour does not attempt to teach UNIX to the completely uninitiated; however, if you’re already familiar with how to log in to the system, you’ll learn how to explore the networking components of it.
It’s not important to know all the major UNIX vendors; the important thing to know is that a lot of different types of UNIX exist. Although some of the ways they handle hard drives and terminals are very different, many of the TCP/IP commands are very much the same.
Let’s take a 20,000-foot view of how most UNIX servers are configured. Yes, they have the capability to do “file and print” the way Windows networks do, and you can connect your Windows 95 drive letters or LPT ports to a UNIX box (if your Windows 95 PC has an appropriate network client loaded). However, more than this, UNIX servers are typically client/server oriented.
By the way, you’ll find very little difference between a UNIX workstation and a UNIX server, other than the speed and redundancy of the hardware.
I’ll get into client/server a bit more in Hour 18, “Lots of Different People in Your Neighborhood.” For now, it’s enough to know that client/server is basically a fancy way of saying, “If I ask somebody for a price of a widget, they give me an answer.” (This is unlike file and print, where you would get the entire catalog.) Think of client/server as being question/answer oriented. For example, DNS name services are a great example of client/server. When you pull up www.jotto.com, you don’t ask your name server for a list of everyone in the .com zone; instead, you ask it for the IP address of www.jotto.com. It responds with 205.134.224.21. It’s a very simple transaction. The client asks the questions, and the server provides the answers. If configured to do so, any machine can act as either the client or the server.
You know the way every salesperson who walks in your door makes sure to mention e-business, VPN, and extranet? That’s how it used to be with client/server. It was a hugely overused marketing term a couple of years ago. However, although client/server is now out of favor with marketing types, it describes reasonably well what’s happening with UNIX services.When I’m teaching a class, I usually refer to any service networking that’s not file and print as service-oriented networking, but because nobody else in the world uses that term, I’ll stick with client/server here.
As with any computer, you network a UNIX computer by sticking a network card into its motherboard, plugging it into a hub, turning the computer on, configuring it, and away you go. Not so hard, huh? The trick with UNIX is that the only standards that exist are TCP/IP-based standards. There are no standards for NetBEUI and IPX/SPX; however, these are available through third parties as vendor add-ons (and are beyond the scope of this book).
UNIX servers tend to house mission-critical databases as well as service users via client/server applications. In the past, this has largely been via Telnet, a way of running a character-based terminal session on a UNIX computer over the network. Lately, this is being replaced by graphical Windows front ends that do pretty much the same thing (although they might communicate with the UNIX host on a different socket number). Most of this communication is via TCP/IP.
Because TCP/IP seems to win nowadays, it’s not much of an obstacle. UNIX’s chief problem with most people is that it has many, many cryptic commands that must be typed in to configure the computer. Even though UNIX had a windowing system (called X Window) before Windows 3.1 was a gleam in Bill Gates’s eye, it has always been a bit “user hostile”—requiring users to edit many configuration files while acting unfor-givingly when they made mistakes. In a nutshell, UNIX’s windowing system, though finally maturing in the last couple of years, has been a real problem. There aren’t any standard ways to configure the network through the window system; therefore, I’m going to talk about command-line network configuration and troubleshooting instead. Don’t let that deter you—think of it as an excuse to brush up on your typing. What’s more, once you learn this stuff, much of it works under Windows9x and NT—it’s just hidden behind the scenes (Microsoft did a great job at making basic network configuration a pretty painless experience).
I know a lot of people who have been scared by the prospect of playing with their production UNIX systems and have bought a $29 CD-ROM of the Linux operating system, a freely distributed UNIX “workalike.” Many people install this to a pretty low-end PC and learn on it. I recommend this highly—you won’t be afraid to “learn by destroying,” which is one of the best ways to learn. You’ll also do an install of what seems to be a complex operating system, and you’ll discover that it was actually pretty easy. It’s a good way to demystify a seemingly scary endeavor.Many commercial UNIX vendors have begun to offer free single-user versions of their UNIX flavors, too, for just this purpose. If you happen to have a commercial version of UNIX in production that you want to learn about, you’re sitting pretty—it’s always best to learn with exactly what you have in production. SCO (www.sco.com) and Sun (www.sun.com), for example, have this policy. (They do charge for shipping and handling, but last time I checked, it was a nominal charge.)
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