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Revision as of 14:45, 30 November 2010 by Mdomsch (talk | contribs) (Release Notes)

Consistent Network Device Naming


On Dell and HP servers with multiple network ports on the motherboard, name them lomX rather than ethX.


Current status

  • Targeted release: Fedora 15
  • Last updated: 2010-11-13
  • Percentage of completion: 75%

Detailed Description

Systems, particularly servers, with multiple network ports, name the ports ethX in a non-deterministic order, and are therefore not useful for system administrators.

The proposal is as follows:

Benefit to Fedora

System Administrators can then use BIOS-provided names, which are consistent and not arbitrarily named, for their network ports. This eliminates the confusion that non-deterministic naming brings, and eliminates the use of hard-coded MAC address based port renaming which a) is racy and error-prone, and b) introduces state into an otherwise stateless system.

This is only known to affect Dell PowerEdge 10G and newer servers, and HP 5G and newer servers, that expose network port labels in SMBIOS.


  • See above

How To Test

  • System-Under-Test must be a Dell PowerEdge 10g or newer server (PE 1950 III class, or R610 class), or HP ProLiant 380 (5G or 6G).
  • biosdevname must be installed on the target system.
  • erase /lib/udev/rules.d/70-persistent-net.rules file. This is where naming is persisted across reboots.
  • reboot the system
  • Following reboot:
    • /sbin/ifconfig -a must show LAN-on-Motherboard ports named lom[1234]
    • lom[1234] must correspond to the chassis labels. Verify using ethtool -p lom[1234] and watch the lights blink.
    • /lib/udev/rules.d/70-persistent-net.rules should now have rules for lom[1234] and should correspond to chassis labels.
  • Testing within anaconda TBD

User Experience

LAN-on-Motherboard ports will be named lom[1234] rather than ethX



Contingency Plan

None necessary, revert to previous release behaviour.


Release Notes

  • Servers often have multiple Ethernet ports, either embedded on the motherboard, or on add-in PCI cards. Linux has traditionally named these ports ethX, but there has been no correlation of the ethX names to the corresponding chassis labels. Starting in Fedora 15, Ethernet ports on servers will have a new naming scheme to provide physical reference locations, rather than ethX. Ethernet ports embedded on server motherboards will be named em<port_number>, while ports on PCI cards will be named pci<slot_number>#<port_number>_<virtual_device_number>, corresponding to the chassis labels. Existing installations upgraded to Fedora 15 will not see a change in names unless /lib/udev/rules.d/70-persistent-net.rules is deleted and the HWADDR lines are removed from all /etc/sysconfig/network-scripts/ifcfg-* files.

This feature affects Dell PowerEdge 10G and newer servers (PowerEdge 1950 III family, PowerEdge R710 family, and newer), and HP ProLiant G6 servers and newer.

Comments and Discussion