IPX/SPX basics

by Johannes Helmig [Published on 7 June 1998 / Last Updated on 7 June 1998]

Ethernet Network cards communicate using the MAC-addressing: the Ethernet address programmed into the network card by the manufacturer. You can view the Ethernet-address using the configuration program of the Network card (if it has one), like in this example for the 3C509:


If you have the TCP/IP protocol installed, you can use "WINIPCFG" to display the MAC-address (start it via the RUN-menu):

The first 6 digits of the Hexadecimal MAC-address indicate the manufacturer (large manufactures have several ID-codes), the last 6 digits are a unique number assigned by the manufacturer for each card.

This MAC/Ethernet-address is UNIQUE world-wide !

To understand now some of the requirements on setting up and configuring the IPX/SPX network protocol, it helps to understand the history of this protocol:

It was developed by NOVELL for for its PC-based fileserver product called "Netware". Multiple network boards can be installed in a Netware server, which is often done to improve network performance.

For EACH network-card with its attached network-cable, a NET-number is assigned on the Netware server (in addition, each Netware server requires an internal NET-number for itself).
These NET-numbers must be UNIQUE on the complete network.

The complete Network-address of a system using IPX/SPX-protocol is now the combination of NET-number and MAC-address (example for PC#1 on NET=2 using the 3C509 card listed above: 2.0060086DD3EE, for the PC#3 on NET=3 using the NE2000 listed above: 3.080000060560).

Since the original specification of the IPX/SPX-protocol by NOVELL, changes had to be made to the protocol, so that there are now MULTIPLE versions of the IPX/SPX-protocol, which differentiate by the FRAME-type:

- Ethernet 802.3
- Ethernet 802.2
- Ethernet_II

(When loading the NOVELL-drivers on a DOS-system, the FRAME-type MUST be defined in the NET.CFG file).

When using IPX/SPX-protocol on a Windows95 or Windows NT4 system to connect to a NOVELL-Netware or Windows NT server, it is very easy:

When installing a Network card, Windows95 installed a default set of Clients and protocols, which includes the IPX/SPX protocol.

If you are ONLY connecting to a NOVELL-Netware server, you can delete the not required components.

In this case, I started on my system, which is already configured with a Modem and TCP/IP for Internet connection. I am now loading the IPX/SPX Protocol.

Let's now look at the Configuration (=Properties) of the IPX/SPX protocol :

Tab: Advanced tem: Frame-Type: By default, the value is: AUTO.

When connecting to a Novell Netware server or Microsoft Windows NT server, leave the Frame-Type on AUTO: your System will sense on the network the appropriate Frame-Type and will use it them automatically.

But what, when you are using IPX/SPX to communicate between Windows95 systems in a PC-to-PC network and there is NO Novell or NT server on the network?

Since there is no server, the IPX/SPX-Frame-Type is not NOT defined on the network, so the default FRAME-Type setting of AUTO will NOT work! So, in such cases, you MUST configure yourself the Frame-type:

Select now a Frame-Type.

I usually select the Frame-Type: "Ethernet 802.3".

Please, also make sure, that on ALL systems, the IPX/SPX Network-address is the SAME.

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