RHCE Training RHEL7-Revert to Old Nic Naming

In RHCE training RHEL7. You must have noticed that while checking network interface names, you don’t see traditional eth0, eth1 … etc.

Red Hat Enterprise Linux 7 provides methods for consistent and predictable network device naming for network interfaces. These features change the name of network interfaces on a system in order to make locating and differentiating the interfaces easier.

Traditionally, network interfaces in Linux are enumerated as eth[0123…], but these names do not necessarily correspond to actual labels on the chassis. Modern server platforms with multiple network adapters can encounter non-deterministic and counter-intuitive naming of these interfaces. This affects both network adapters embedded on the motherboard (Lan-on-Motherboard, or LOM) and add-in (single and multiport) adapters.

During your RHCE training, you must have learned that by default, systemd will name interfaces using the following policy to apply the supported naming schemes:

Scheme 1: Names incorporating Firmware or BIOS provided index numbers for on-board devices (example: eno1), are applied if that information from the firmware or BIOS is applicable and available, else falling back to scheme 2.

Scheme 2: Names incorporating Firmware or BIOS provided PCI Express hotplug slot index numbers (example: ens1) are applied if that information from the firmware or BIOS is applicable and available, else falling back to scheme 3.

Scheme 3: Names incorporating physical location of the connector of the hardware (example: enp2s0), are applied if applicable, else falling directly back to scheme 5 in all other cases.

Scheme 4: Names incorporating interface’s MAC address (example: enx78e7d1ea46da), is not used by default, but is available if the user chooses.

Scheme 5: The traditional unpredictable kernel naming scheme, is used if all other methods fail (example: eth0).

(reference: access.redhat.com)