In my Daily Drill Down ”An Exchange alternative: Mercury Mail Transport System can be installed on your client,” I explained how to install Mercury Mail Transport System (Mercury/32) on your NT 4.0 Workstation to work as a LAN mail server. In this Daily Feature, I’ll cover how to set up networking in Windows NT 4.0 to use Mercury/32.

The Mercury/32 core module allows you to define the operations of Mercury/32. The module defines how Mercury/32 should access your LAN. Before you can configure your Mercury/32 core module, you must have already set up certain addresses and protocols for your LAN. The addresses and network protocols you’ll need for Mercury/32 are typically added either when you install your NT 4.0 Workstation or when you add networking services to your NT 4.0 system. If you haven’t added this network support to your NT 4.0 machine, you’ll need to add the TCP/IP protocol and the IP address for your network interface card (NIC).

Your NIC is not the same as your modem. The modem IP address is typically a dynamically assigned IP address value defined by your Internet service provider (ISP). Because the Mercury/32 core module requires that you define certain protocols and IP addresses for your LAN, it is important for you to understand how to configure your NT 4.0 Workstation networking services.

Configuring NT 4.0 Workstation networking services
There are a couple of ways you can access your Network dialog box. I usually right-click on the Network Neighborhood icon on my desktop and then select Properties. If you don’t find the Network Neighborhood icon on your desktop, it is probably because networking services haven’t been set up for your NT 4.0 Workstation. If this is the case, then you’ll need to click Start | Settings | Control Panel. Once you’ve opened Control Panel, double-click the Network icon. Either method will give you the Network dialog box (see Figure A).

Figure A
Bring up the Network dialog box to begin configuring Windows NT 4.0 Workstation.

Once you’ve opened the Network dialog box, you will see five tabs: Identification, Services, Protocols, Adapters, and Bindings. Click the Adapters tab, shown in Figure B.

Figure B
Choose the Adapters tab to find your NIC.

On the Adapters tab, you should see a list of all of the NICs you’ve installed on your NT 4.0 system. You should see at least one NIC if you’re using a LAN. Make a note of the NIC’s name and then select the Protocols tab, shown in Figure C.

Figure C
The Protocols tab shows you a list of network protocols you’ve enabled.

The Protocols tab displays a list of network protocols enabled for your LAN. You should see TCP/IP Protocol in your list of protocols.

Setting up IP addresses
If you don’t see TCP/IP Protocol in your list of network protocols, this means you haven’t defined an IP address for your NIC. In this case, you’ll need to add the protocol by clicking the Add button, scrolling down the list of protocols until you find TCP/IP Protocol, and then double-clicking on that entry.

The recommended IP addresses for LANs are typically Class A ( or Class B ( Another class, Class C, is typically used by your ISP. Class C IP addressing is also known as routable IP addressing. It is the same sort of IP addressing that your ISP uses to access remote networks.

Now that we have a little better understanding of what IP addressing actually is, let’s go ahead and click once on the TCP/IP Protocol entry and then click the Properties button. As you can see in Figure D, the TCP/IP Properties sheet contains IP Address, DNS, WINS Address, and Routing.

Figure D
Open the TCP/IP Properties sheet.

Assigning your NIC
Earlier, I asked you to make a note of your NIC. What you want to do now is verify that the Adapter box of the TCP/IP Properties sheet shows the name of your NIC. If it doesn’t show your NIC, then select the appropriate adapter for your machine from the drop-down list.

Assigning an IP address for your NIC
Typically, you’ll find that NT 4.0 Workstation assumes you’re connecting to a DHCP server in order to obtain an IP address for your NIC. To verify this, you can take a look at the lower half of the TCP/IP Properties sheet. If the option Obtain An IP Address From A DHCP Server is enabled, your NT 4.0 Workstation network assumes you have a remote domain server that dynamically provides an IP address for your NIC.

To make Mercury/32 your local mail server (or to replace the Microsoft Exchange Server with the simpler and much faster Mercury/32 mail server), you need to change your Workstation networking service to Specify An IP Address. To do this, click the radio button next to Specify An IP Address. This allows your machine to have the same IP address every time it is rebooted. By specifying an IP address, you tell NT 4.0 networking to enable static IP addressing. Static IP addressing has absolutely no effect on your dial-up networking.

Decide which class of IP addressing you want to use. I suggest you use either the Class A or the Class B IP addressing. Class A is best for a small LAN. Class B is best for a midsize to very large LAN. Class C, which allows you to access the largest number of machines, is used by ISPs when they are assigning remote IP addresses to dial-up, DSL, or cable modems.

Once you’ve decided on an IP addressing scheme, enter the IP address for your machine’s NIC in the IP Address box. Next, enter the subnet mask in the Subnet Mask box:

  • For Class A IP addresses, this will be
  • For Class B IP addresses, this will be
  • For Class C IP addresses, this will be

Note that if you add a subnet mask, you will need to use the same one on every machine that is part of your LAN. While a subnet mask isn’t required, it’s recommended because this mask allows the LAN and your machine to portion out and access chunks of your network much more efficiently than if the subnet mask were not used.

The last item in the TCP/IP Properties sheet’s IP Address tab is the Default Gateway IP Address. In 90 percent of those cases where a LAN is being used, this IP address may be left blank. If you haven’t already, you’ll need to assign a different static IP address for every machine that is attached to your LAN. Mercury/32 uses the static IP addresses in much the same way that the mail carrier uses your home address for delivering (and picking up) mail.

Once you’ve finished your configuration, go ahead and close all your open properties sheets until you’ve exited the Network dialog box. If you have made any changes to your network, the system will ask you if you want to restart your system. Restart your system to effect your changes.
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