Ubuntu

Network Interface names

Asked by Cham

I have two identical machines that have different network interface names.
The first uses em1 to em4, the second eno1 to eno4.
The machines need the same firewall and routing configuration so different network interface names is annoying.

Dmesg entries
first:
[ 2.662934] tg3.c:v3.137 (May 11, 2014)
[ 2.676627] tg3 0000:02:00.0 eth0: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:87:fc
[ 2.676632] tg3 0000:02:00.0 eth0: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.676635] tg3 0000:02:00.0 eth0: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.676637] tg3 0000:02:00.0 eth0: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.693708] tg3 0000:02:00.1 eth1: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:87:fd
[ 2.693713] tg3 0000:02:00.1 eth1: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.693716] tg3 0000:02:00.1 eth1: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.693719] tg3 0000:02:00.1 eth1: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.708755] tg3 0000:03:00.0 eth2: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:87:fe
[ 2.708759] tg3 0000:03:00.0 eth2: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.708762] tg3 0000:03:00.0 eth2: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.708764] tg3 0000:03:00.0 eth2: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.724801] tg3 0000:03:00.1 eth3: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:87:ff
[ 2.724805] tg3 0000:03:00.1 eth3: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.724807] tg3 0000:03:00.1 eth3: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.724809] tg3 0000:03:00.1 eth3: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.821625] tg3 0000:02:00.0 em1: renamed from eth0
[ 2.885817] tg3 0000:03:00.0 em3: renamed from eth2
[ 2.924471] tg3 0000:02:00.1 em2: renamed from eth1
[ 2.944903] tg3 0000:03:00.1 em4: renamed from eth3

second:
[ 2.666098] tg3.c:v3.137 (May 11, 2014)
[ 2.682226] tg3 0000:02:00.0 eth0: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:78:bd
[ 2.682231] tg3 0000:02:00.0 eth0: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.682234] tg3 0000:02:00.0 eth0: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.682236] tg3 0000:02:00.0 eth0: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.702165] tg3 0000:02:00.1 eth1: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:78:be
[ 2.702169] tg3 0000:02:00.1 eth1: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.702172] tg3 0000:02:00.1 eth1: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.702174] tg3 0000:02:00.1 eth1: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.718341] tg3 0000:03:00.0 eth2: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:78:bf
[ 2.718346] tg3 0000:03:00.0 eth2: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.718348] tg3 0000:03:00.0 eth2: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.718351] tg3 0000:03:00.0 eth2: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.734580] tg3 0000:03:00.1 eth3: Tigon3 [partno(BCM95720) rev 5720000] (PCI Express) MAC address 44:a8:42:04:78:c0
[ 2.734584] tg3 0000:03:00.1 eth3: attached PHY is 5720C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1])
[ 2.734586] tg3 0000:03:00.1 eth3: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1]
[ 2.734589] tg3 0000:03:00.1 eth3: dma_rwctrl[00000001] dma_mask[64-bit]
[ 2.736221] tg3 0000:02:00.0 eno1: renamed from eth0
[ 2.746063] tg3 0000:02:00.1 eno2: renamed from eth1
[ 2.757994] tg3 0000:03:00.0 eno3: renamed from eth2
[ 2.781995] tg3 0000:03:00.1 eno4: renamed from eth3

The first system was upgraded from 14.X.X LTS to 16.04.2 LTS. The second was freshly installed.

As far as I understand the PredictableNetworkInterfaceNames the intrerfaces should have an enoX name instead of the emX. How can I get the two systems behave in the same way without overruling the default behavior.

Thanks,

Cham

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Revision history for this message
Cham (cham-soops) said : 		#1

I found out why the difference occurred:

The second machine didn't have the biosdevname package installed.
Now both machines have emX interface names.

Is it better to have the biosdevname package installed or not?

Revision history for this message
actionparsnip (andrew-woodhead666) said : 		#2

If it works then awesome :)

Revision history for this message
Cham (cham-soops) said : 		#3

I removed the biosdevname package so the interface naming will go back to the default enoX.
I was confused about the emX network names since they are not mentioned in the PredictableNetworkInterfaceNames and searching didn't give an answer either.