Why NIC renames in CentOS ? (e.g. eth0 renamed to eth3)

CentOS
#1

HI
I installed new CentOS 6.4 on my system . and when i tried to set a static IP address. I noticed the NIC name has changed to something else. for example i was looking out for eth0 but there wasn’t.
Also when I add new NIC to my virtual machine on ESXi Also i have same problem .

Why this happen ? And how can be fixed???

Thanks

#2

First open /etc/udev/rules.d/70-persistent-net.rules file and change the mac address and interface name to eth0.

Change-NIC-Name-in-CentOS-6.png720×400 14.5 KB

Next, rename the current network interface name from eth3 to eth0 as shown.

# cd etc/sysconfig/network-scripts/
# mv ifcfg-eth3 ifcfg-eth0

Now open and edit the file ‘ifcfg-eth0’ and change change the mac address and interface name to eth0.

# vi ifcfg-eth0

After making network changes, don’t forget to restart the network to take new configuration into effect and check the ip address again with ifconfig command.

# service network restart
# ifconfig -a
1 Like
#3

Hi

First of all find out the mac address of your interface cards

[root@devmillennium-web ~]# ifconfig -a | grep -i --color hwaddr

eth0 Link encap:Ethernet HWaddr **xx:xx:xx:xx:xx:xx**

To rename eth3 as eth0, edit a file called 70-persistent-net.rules in /etc/udev/rules.d/ directory.

# vi /etc/udev/rules.d/70-persistent-net.rules

The names of the Ethernet devices are listed in this file as follows:

# PCI device 0x14e4:0x1680 (tg3)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="**n6:cd:6f:45:32:e6**", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="**eth0**"

Here change the mac address to your networkinterface mac address xx:xx:xx:xx:xx:xx and change name of the interface from eth3 to eth0.

and now reboot the server or kindly follow the steps which are said by ravi

#4

Hi dears,
thanks for your quick answer.
can you explain more about this file , i mean 70-persistent-net.rules ?
and when this rule execute ?
Also i’ve add new NIC to my virtual machine. but there weren’t any ifcfg-ethx in /etc/sysconfig/network-script. shall i add same line as below in this (70-persistent-net.rule) file ?

#5

@millad90s

I think this file holds the system network related configuration and it executes when system boots up…First check your new NIC is detected by using following command.

# lspci | egrep -i --color 'network|ethernet'

After detecting you can add the below rule to the file and don’t forget to change MAC and name of the Ethernet…

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?", ATTR{address}=="**n6:cd:6f:45:32:e6**", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth", NAME="**eth0**"
After making changes, **reboot** the system and edit **ifcfg-eth0** and update MAC of your new NIC card.
#6

Hi

you can also use the below command to find out the info about your nic card

#/usr/sbin/lshw -class network

#7

@millad90s

if u find any difficulties with this file U need to run below command after changes to ifcfg-eth* file.
#start_udev

it will create automatically with info ifcfg-eth* file after running this command

#8

hi thanks for your answer .
but lshw is not installed by default .
in which package i can find it??

#9

Just do a yum or apt to get the lshw package. For example do as shown below.

# yum install lshw        [on CentOS alike systems]
# apt-get install lshw    [on Debian alike systems]
1 Like