8.2. Understanding the Device Renaming Procedure

The device name procedure in detail is as follows:
  1. A rule in /usr/lib/udev/rules.d/60-net.rules instructs the udev helper utility, /lib/udev/rename_device, to look into all /etc/sysconfig/network-scripts/ifcfg-suffix files. If it finds an ifcfg file with a HWADDR entry matching the MAC address of an interface it renames the interface to the name given in the ifcfg file by the DEVICE directive.
  2. A rule in /usr/lib/udev/rules.d/71-biosdevname.rules instructs biosdevname to rename the interface according to its naming policy, provided that it was not renamed in a previous step, biosdevname is installed, and biosdevname=0 was not given as a kernel command on the boot command line.
  3. A rule in /lib/udev/rules.d/75-net-description.rules instructs udev to fill in the internal udev device property values ID_NET_NAME_ONBOARD, ID_NET_NAME_SLOT, ID_NET_NAME_PATH, ID_NET_NAME_MAC by examining the network interface device. Note, that some device properties might be undefined.
  4. A rule in /usr/lib/udev/rules.d/80-net-name-slot.rules instructs udev to rename the interface, provided that it was not renamed in step 1 or 2, and the kernel parameter net.ifnames=0 was not given, according to the following priority: ID_NET_NAME_ONBOARD, ID_NET_NAME_SLOT, ID_NET_NAME_PATH. It falls through to the next in the list, if one is unset. If none of these are set, then the interface will not be renamed.
Steps 3 and 4 are implementing the naming schemes 1, 2, 3, and optionally 4, described in Section 8.1, “Naming Schemes Hierarchy”. Step 2 is explained in more detail in Section 8.6, “Consistent Network Device Naming Using biosdevname”.