Device has MAC address X, instead of configured address Y.


Recently, we tried to take a network interface down on a VM, when we executed the command

ifdown eth0

we got the following error:

ERROR    : [/etc/sysconfig/network-scripts/ifdown-eth] Device  has MAC address 00:00:00:00:00:00
 00:45:4D:04:02:36
 00:45:4D:04:02:40, instead of configured address 00:45:4D:16:0B:29. Ignoring.

We used ifconfig eth0 to check the information on the network interfaces which resulted in the following data:

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
 inet 10.1.20.115  netmask 255.255.255.0  broadcast 10.1.20.255
 inet6 fe80::215:5dff:fe01:236  prefixlen 64  scopeid 0x20<link>
 ether 00:45:4d:04:02:36  txqueuelen 1000  (Ethernet)
 RX packets 10103919  bytes 5474528935 (5.0 GiB)
 RX errors 0  dropped 0  overruns 0  frame 0
 TX packets 6541413  bytes 1190276207 (1.1 GiB)
 TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

We saw that the value ether for eth0 was 00:45:4d:04:02:36, which was one of the addresses the warning mentioned that are valid.

Apparently, we had an error in the following configuration file:

/etc/sysconfig/network-scripts/ifcfg-eth0

The value for HWADDR was set to 00:45:4D:16:0B:29 which was wrong (most likely this file was copied here from another source), after we updated the value to 00:45:4d:04:02:36 we were able to use the device normally.

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