Every device and every interface has an associated hotplug event, which is processed by udev. Hotplug events are triggered by the kernel when a link to a device is established or removed or when a driver registers or deletes an interface. Since SUSE Linux 9.3, udevd receives and processes hotplug events. Either udevd listens directly to netlink messages from the kernel or /sbin/udevsend must be specified in /proc/sys/kernel/hotplug. udevd configures the device according to a set of rules (see Chapter 33, Dynamic Device Nodes with udev).