DELL APEX CLOUD PLATFORM for Red Hat OpenShift: MAC Address Remains Unchanged After Replacing Network Card in Bond Interface
Summary: MAC Address Remains Unchanged After Replacing Network Card in Bond Interface
Symptoms
After replacing a physical network interface card (NIC), the MAC address of the corresponding network interface (e.g., eno12399np0) or the bond interface (bond0) remains the same as before the replacement. The new NIC's physical MAC address is different, but the operating system still displays the old address.
Cause
This behavior is normal and expected when the network interface is part of a bonded interface (bond0).In a standard Linux bond configuration:· The bond interface inherits the MAC address of the first enslaved interface added to it at the time of bond creation.· This chosen MAC address is then applied to all other slave interfaces within the same bond for operational consistency.· Even after replacing a physical NIC, the bond driver continues to use the originally assigned MAC address for the logical bond interface and its slaves.
Example Scenario·
Bond Interface:
bond0· First Slave: eno12399np0 (Integrated 1, Port 1)· Original MAC of eno12399np0: XX:XX:XX:XX:XX:XX
After replacing the physical NIC in Integrated 1, Port 1:
New NIC's Permanent MAC: YY:YY:YY:YY:YY:YY·
Active/Displayed MAC of eno12399np0: XX:XX:XX:XX:XX:XX (Remains unchanged, inherited from bond0)
Resolution
No action is required if the interface is functioning normally. This is the designed behavior.
To verify the system state:1. Check the interface is UP and part of the bond:
ip link show eno12399np0 => Look for state UP and master bond0 in the output.
You can observe both the permanent (burned-in) and the active (bond-assigned) MAC addresses:
ip link show eno12399np0 => The link/ether field shows the active MAC (belonging to the bond). The permaddr field shows the physical MAC of the new card.
Conclusion:
The persistence of the original MAC address after a hardware replacement is intentional and ensures network stability for the bonded interface. As long as the link state is UP and connectivity is normal, the system is operating correctly.