The IPXNetworkNumber property represents an array of characters that uniquely identifies a frame/network adapter combination ...

The IPXNetworkNumber property represents an array of characters that uniquely identifies a frame/network adapter combination on the computer system. The NetWare Link (NWLink) IPX/SPX-compatible transport in Windows 2000 and Windows NT 4.0 and greater uses two distinctly different types of network numbers. This number is sometimes referred to as the external network number. It must be unique for each network segment. The order in this string list will correspond item-for-item with the elements in the IPXFrameType property.