What is an Intranet?

Preface

If you've done a network setup or two, you know something about networking and how to make it work on your Mac. Since you're reading this online, you probably also know a thing or two about using the various parts of the internet (world wide web, ftp, email, and so forth). What you may not have known, though, is that you can use all of these same programs from the internet on your own personal or office network. An intranet is simply a network based on the same formats and programs as the internet, but that runs on your own Mac.

Why use an intranet? Isn't an AppleTalk network good enough?

If you have experience with small-scale AppleTalk networks, you know that it's pretty easy to set up the necessary services (file and printing sharing) and control who can use what files or printers. Apple built all of the network tools right into the MacOS, so they're easy to find and use. Unfortunately, while it's pretty quick to get these features working, there aren't easy ways to do things like email or group collaboration on projects. An intranet, on the other hand, has the flexibility to handle these kind of tasks using software that is free (or inexpensive) and readily available online. Also, an intranet is not a replacement for an AppleTalk network. You can maintain both kinds of services on the same network; Macs attached to an intranet can still access printers and other Macs through the Chooser, just as they did before.

I've read a number of sources that say TCP/IP-based networks (such as intranets) perform more efficiently than AppleTalk networks by a fair margin. To companies or people that move large files around, this would make a significant difference in work efficiency. To test this theory, I compared the copy time of a 10 megabyte file across a regular (AppleTalk-based) Ethernet network (using PhoneNet connectors) with the time of an (intranet-based) FTP transfer. As far as I could tell, TCP/IP didn't have a speed advantage. It is true, however, that I performed my file transfer on a network with only two Macs that weren't doing anything else at the time. It's entirely possible that TCP/IP networks use less computing power that AppleTalk networks, especially on larger networks. To put it simply, your mileage may vary.

Some Technical Details

You've probably heard the term TCP/IP before, but you may not understand how it applies to networking or intranets. TCP/IP is a combination of two different protocols (Transmission Control Protocol and Internet Protocol) and is the underlying technology for how an intranet moves information around. The two parts, TCP and IP, represent different parts of the networking process. The Internet Protocol handles the source and destination network addresses and Transmission Control Protocol handles the data. Ifyou've heard the term IP by itself before, it's probably been in reference to a specific computer's IP address. Each piece of data that moves around the network has a source and destination IP address; without the IP information, the network would not know for sure where the data should go. Every computer on an intranet has a unique IP address, so that information doesn't accidentally get sent to multiple locations. You can assign IP addresses to your Macs on a temporary or permanent basis, depending on your situation and software. I deal more specifically with IP addresses later, in the setup steps.

While IP deals with addresses, TCP handles the actual data from its source to its destination. When you look at a web page, for instance, a number of things happen. First, your web browser sends out a request to the specified IP address (such as http://www.apple.com/) and asks for a web page. The computer that receives your request sends back the file you requested, in a number of discrete pieces of data; each piece is only a small portion of the complete page. TCP handles the fragmentation of the data at the source, as well as the assembly when it reaches your browser. TCP handles many more tasks as well, but web pages are probably the most familiar. Since TCP and IP are used together so frequently, people usually refer to an intranet (and the internet) as a TCP/IP network.

Web Pages and an Intranet

The worldwide internet explosion stems (essentially) from the emergence of the world wide web and the development of the Mosaic web browser and its derivatives. The web isn't limited exclusively to the world internet, however; you can replicate any web sites or technology from the web on your own intranet with little difficulty. The web operates on a special protocol called Hyper Text Transport Protocol, or HTTP for short. That's why any web page you go to starts with "http://." This protocol handles the transfer of pages (in the form of text files), images, and files from web servers to web browsers. Using the same protocol as the world wide web makes it easier to transfer knowledge of the internet to efficient use of your intranet and to interact with the internet itself. I talk about the specific details of setting up a web server later, in the software setup steps.

Most people use web servers on an intranet to make dissemination of information easier and paper-free. If you want to make an announcement to a large number of people, simply post a page with the information. No memos to send, no paper to recycle, no trash to take out. You can set up pages that monitor the status and timelines of different projects, get feedback from viewers, or monitor inventory. Since you can do all this regardless of the operating system of the viewer, you can mete out the costs ofan intranet in just a short time compared to the costs in office supplies.

Other TCP/IP Services

While web pages are the main focus of the internet, there are some other intranet services you need to be aware of. The foremost of these is electronic mail, a staple of modern communications. In 1990, you probably hadn't heard of email; these days, it's hard to find a single business card without the ubiquitous email address (or two). Fortunately, setting up an email server for your intranet doesn't need to be difficult or expensive. Small intranets with a limited amount of email traffic can get by with an inexpensive (or even free) email server runing on a low-end Mac. Larger companies can purchase a more powerful commercial server to handle their communications needs.

The internet doesn't just handle web pages and email, though; another service you'll find useful is FTP, which stands for File Transfer Protocol. Just like its name indicates, FTP handles the transfer of files between networked computers. Since FTP transfer is very similar to normal Macintosh file sharing, setting up an FTP server on an intranet is little trouble for those who already have AppleTalk network experience.

Stuff to remember

Intranets provide internet-like services to a network, regardless of the user's operating system. They can coexist with AppleTalk networks and don't need any special hardware to function.

Stuff to forget

You don't need to remember too much about the technical details (TCP/IP and so forth) to use intranets. I cover any absolutely necessary tech info in the setup instructions.

Need more info? Still have questions?

Problem still not solved? Questions linger? If so, please send mail and I'll do my best to help out. I try to answer all mail with 24 hours, although it can take longer if the answer requires some research.