Old ethX numbering not used when swapping network cards

  • 3687342
  • 20-Nov-2006
  • 30-Apr-2012

Environment

Novell Linux Desktop 9
Novell Open Enterprise Server (Linux based)
Novell SUSE Linux

Situation

When swapping network cards in SUSE Linux, old ethX identifiers will not be used for the new card. For example, if a machine has a single NIC identified as eth0 and that NIC is swapped out the new NIC will use eth1, not eth0.

Resolution

This behavior is governed by the persistent device identifier set in /etc/udev/rules.d/30-net_persistent_names.rules. Contained in this file is a line for each NIC, such as:
SUBSYSTEM=="net", ACTION=="add", SYSFS{address}=="00:15:60:ed:b7:5b", IMPORT="/lib/udev/rename_netiface %k eth0"
This line maps a MAC address to an identifier. To cause a new NIC to use an old identifier, remove the old line and restart the server. After configuring the new NIC, it will use the old identifier.