IPX/SPX – Compatible Protocol

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Definition of IPX/SPX – Compatible Protocol in The Network Encyclopedia.

IPX/SPX stands for Internetwork Packet Exchange/Sequenced Packet Exchange is a set of network protocols that provide packet switching and sequencing for small and large networks, used initially on networks using the Novell NetWare operating systems. Shortly after, they became widely used on networks deploying Microsoft Windows LANs, as they replaced NetWare LANs.

ipx/spx compatible protocol

IPX works at layer 3 of the Open Systems Interconnection (OSI) model and SPX works at layer 4.

Microsoft’s version of the Novell NetWare IPX/SPX (Internetwork Packet Exchange/Sequenced Packet Exchange) protocol for Microsoft Windows 95, Windows 98, and Windows 2000 is called IPX/SPX-Compatible Protocol.

IPX/SPX-Compatible Protocol supports the 32-bit Windows Sockets 1.1 and NetBIOS over Internetwork Packet Exchange (IPX) programming interfaces.

IPX/SPX implementation

Novell is largely responsible for the use of IPX as a popular computer networking protocol due to their dominance in the network operating system software market (with Novell Netware) from the late 1980s through the mid-1990s. IPX/SPX was standard for DOS-era multi-user network games.

Because of IPX/SPX’s prevalence in LANs in the 1990s, Microsoft added support for the protocols into Windows’ networking stack, starting with Windows for Workgroups and Windows NT. Microsoft even named their implementation “NWLink”, implying that the inclusion of the layer 3/4 transports provided NetWare connectivity. In reality, the protocols were supported as a native transport for Windows’ SMB/NetBIOS, and NetWare connectivity required additional installation of an NCP client (Microsoft provided a basic NetWare client with Windows 95 and later, but it was not automatically installed, and initially only supported NetWare bindery mode).

NWLink was still provided with Windows (up to and including Windows Server 2003), but it is neither included with nor supported in Windows Vista. Its use is strongly discouraged because it cannot be used for Windows networking except as a transport for NetBIOS, which is deprecated.

IPX/SPX on Windows 95/98

Although the Windows 95 and Windows 98 user interfaces allow you to configure multiple bindings for IPX/SPX-Compatible Protocol to multiple network interface cards (NICs), only the first binding is actually used. You cannot use IPX/SPX-Compatible Protocol for connecting to NetWare over an ARCNET network; you must install real-mode IPX drivers instead.

IPX/SPX-Compatible Protocol tip

IPX/SPX-Compatible Protocol is set by default to autodetect the frame type used on a NetWare network. If no frame type is detected, the default 802.2 type is used. If multiple frame types are detected, the predominant one is selected.


IPXROUTE is a Microsoft Windows NT and Windows 2000 utility for viewing and modifying Internetwork Packet Exchange (IPX) routing table information when NWLink IPX/SPX-Compatible Transport is installed on machines running Windows NT and Windows 2000.

You can use ipxroute to display the current IPX settings, such as frame type, IPX network numbers, and internal network number. You can also use it to display the IPX routing table, Service Advertising Protocol (SAP) table, and IPX routing statistics.

Ipxroute example

The Ipxroute Table command shows the IPX routing table, while Ipxroute Config shows binding information for IPX, such as the IPX network number.

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