Clearly since you are reading this web page, you probably know what the Internet and TCP is all about. To most people, the Internet is a "global" network of networks, and any given computer on the 'net has it's own unique IP address, etc, etc.

But, did you know you can set up your own TCP/IP network? Yes, you can! You don't hear about this much since it is of only limited use on small or "closed" networks, since you are generally better off using a more native protocol (Appletalk for Macs, NetBIOS or IPX for Windows) for printing, filesharing, etc.

However, a TCP network may be convenent for sharing files between Macs and PCs, or for that occational game that doesn't support any other common protocol.

First, a little background, so that we are all clear on what the numbers mean and do. This will help you understand and troubleshoot your own TCP network:

1. Connect via: This is the physical connection setting that determines how TCP is going to talk to the world. Most commonly, this will be set to 'Ethernet' or 'PPP' (or some variant, such as 'FreePPP'). PPP is the setting if it's likely routed over the modem.
2. Configure: Configuring options; how your machine gets it's IP and network information. If you have a static IP (a perminantly assign IP address), this would likely be set to 'Manually'. Sometimes, IP addresses are assigned dynamically, in which case you'd have it set to 'bootp' or some-such. Your friendly network adminstator will tell you what to set this at.
3. IP Address: Your uniquely assigned number. If you dial into a network, this may be dynamically assigned (for example, an ISP may have 50 modems, so they need only 50 IP addresses that are assigned to those modems).
4. Subnet Mask: This number is usually set at '255.255.255.0'. This number acts as a mask, and tells the computer to ignore all the numbers above the last group. The result is faster performance, since it only has to resolve the last numbers (i.e. the computer only sees 'xxx.xxx.xxx.147', instead of having to figure out the entire IP number).
5. Router Address: This is the IP address of your Internet router. A router acts as a gateway between your physical local network and the world (i.e. Internet) beyond, keeping traffic on your LAN from being braodcasted to the world (and vice-versa, depending on your router configuration). Your network administrator is who worries about this, you only need the IP.
6. Name Server Address: This is the IP of the dedicated server, and in many ways forms the backbone of the internet. Every time you talk to another computer, web page, or ftp server, your computer talks to the Name Server (DNS) to find the IP address of the target computer so you're able to talk to it.
7. Search Domains: This is more or less tells the computer to search the specified domain for any other Domain Name Servers (DNS), in case the ones you specified are no longer valid. This is optional, since on most networks there are computers set up to automaticly step in, in case the main DNS goes down (30 seconds is usually the defualt rollover, so you'll definitely notice a network lag if the DNS is down). This is often in name form, such as 'nwu.edu'.

Some Conventions:

Technically, for IP addresses, you can use any number between 1 and 254. The numbers 0 and 255 are "reserved" for broadcast and should never be used (unless, of course, you're a network administrator and really, really know what you are doing).

Standard convention designates subnet 192 to "private" or closed networks (networks that have no outside link). Since your network will not be physically connected to the internet and you can technically use any number you'd like, there really isn't any reason to do so.

With that out of the way, lets get onto setting up your own private TCP network.

I'm assuming that you have a working Ethernet network (you cannot set up a private TCP network between Macs & PCs over a localtalk network, simply because you cannot connect PCs to that type network. There is really no point to creating an all Mac TCP network, even though it is possible).

Perhaps the best way to explain this is with the help of an example network. Lets presume that we have an Ethernet network of 5 computers. Lets assign those computers IP addresses now (notice the 192 subnet): 192.100.100.101, 192.100.100.102, 192.100.100.103, 192.100.100.104, 192.100.100.105.

Step 1:

	On your first Macintosh, open SimpleText, create an new document and save it inside your System Folder as Hosts.

	Assigning 192.100.100.101 to this computer, enter the IPs of the other computers, simply hitting 'Return' between each address:

Step 2:

Open the TCP/IP control panel. From the 'File' menu, select 'Configurations...'. Click on the default configuration and click 'Duplicate'. It'll ask you to name the configuration, name it something like "Home Network". You can see from my screenshot that I've renamed the former "default" configuration to "Dial-up" so I can see at a glance which configuration is selected (the configuration setting will show up in the title bar of the main TCP/IP window).

	Under the 'Edit' menu, select 'User Mode...' and set the user mode to 'Advanced' and click ok. You'll notice that the advanced settings adds a couple more fields. Click the 'Select Hosts File...' and select the Hosts file that you created on step 1.

That's it! You've configured your first Mac! Now, repeat the configuration for each of the other computers.

You can use the 'Configurations...' (under the File menu) to switch between your "Dial-up" and "Home Network" settings.

Configuring TCP/IP for Windows 95

This section under construction. I've gotten reports that you can create a text file (the same way as outlined above for the Mac) and put it in the Windows directory, that'll perform much the same way. I haven't confirmed this myself, but I don't doubt it. I just want to test it to make sure I get the steps down, etc.

If you have any further info or insights that you think could help me, please contact me.

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