Книга: Linux Network Administrator Guide, Second Edition

The ipx_configure Command

The ipx_configure Command

Each IPX interface must know which IPX network it belongs to and which frame type to use for IPX. Each host supporting IPX has at least one interface that the rest of the network will use to refer to it, known as the primary interface. The Linux kernel IPX support provides a means of automatically configuring these parameters; the ipx_configure command enables or disables this automatic configuration feature.

With no arguments, the ipx_configure command displays the current setting of the automatic configuration flags:

# ipx_configure
Auto Primary Select is OFF
Auto Interface Create is OFF

Both the Auto Primary and Auto Interface flags are off by default. To set them and enable automatic configuration, you simply supply arguments like these:

# ipx_configure --auto_interface=on --auto_primary=on

When the --auto_primary argument is set to on, the kernel will automatically ensure that at least one active interface operates as the primary interface for the host.

When the --auto_interface argument is set to on, the kernel IPX driver will listen to all of the frames received on the active network interfaces and attempt to determine the IPX network address and frame type used.

The auto-detection mechanism works well on properly managed networks. Sometimes network administrators take shortcuts and break rules, and this can cause problems for the Linux auto-detection code. The most common example of this is when one IPX network is configured to run over the same Ethernet with multiple frame types. This is technically an invalid configuration, as an 802.2 host cannot directly communicate with an Ethernet-II host and therefore they cannot be on the same IPX network. The Linux IPX network software listens on the segment to IPX datagrams transmitted on it. From these, it attempts to identify which network addresses are in use and which frame type is associated with each. If the same network address is in use with multiple frame types or on multiple interfaces, the Linux code detects this as a network address collision and is unable to determine which is the correct frame type. You will know this is occurring if you see messages in your system log that look like:

IPX: Network number collision 0x3901ab00
eth0 etherII and eth0 802.3

If you see this problem, disable the auto-detection feature and configure the interfaces manually using the ipx_interface command described in the next section.

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