No file for eth0

sudo_su · 12-25-2012, 11:53 AM

Dear experts,

I installed CentOS into my laptop's harddisk while detaching it from laptop and connecting it to my server via USB cable. The CentOS is installed and when i plug the harddisk back to my laptop, it simple started working.

The problem is that

Code:

/etc/sysconfig/network-scripts

has entries

Code:

ifcfg-em1,ifcfg-em2, ifcfg-em3, ifcfg-em4

which are the 4 gigabit interfaces on my server, now as i put this harddisk into my laptop and plugged network cable, tough it started working but I am unable to find ifcfg-eth0 in network-scripts directory.

The ifconfig shows

Code:

eth0

which successfully obtains IP from one of my dhcp servers in my LAN.

I dont want dynamic IP and am unable to find ifcfg-eth0 so I configure it with my required IP. I tried

Quote:

find /etc -name "*eth0"

but couldnt locate the file. I guess its in running configuration.

What can I do to have ifcfg-eth0 so i configure it with my required IP.

Regards.

teckk · 12-25-2012, 12:06 PM

Have you tried the network config tool system-config-network
http://www.centos.org/docs/5/html/De...nterfaces.html
http://www.centos.org/docs/5/html/De...rk-config.html

sharadchhetri · 12-25-2012, 12:10 PM

Quote:

Originally Posted by sudo_su

Dear experts,

I installed CentOS into my laptop's harddisk while detaching it from laptop and connecting it to my server via USB cable. The CentOS is installed and when i plug the harddisk back to my laptop, it simple started working.

The problem is that

Code:

/etc/sysconfig/network-scripts

has entries

Code:

ifcfg-em1,ifcfg-em2, ifcfg-em3, ifcfg-em4

which are the 4 gigabit interfaces on my server, now as i put this harddisk into my laptop and plugged network cable, tough it started working but I am unable to find ifcfg-eth0 in network-scripts directory.

The ifconfig shows

Code:

eth0

which successfully obtains IP from one of my dhcp servers in my LAN.

I dont want dynamic IP and am unable to find ifcfg-eth0 so I configure it with my required IP. I tried but couldnt locate the file. I guess its in running configuration.

What can I do to have ifcfg-eth0 so i configure it with my required IP.

Regards.

this is not a problem. are you confused after seeing ifcfg-em* files

So FYI

Ethernet NICs embedded on the motherboard will be named em[1234] rather than ethX. PCI add-in card NICs will be named p<slot>p<port>_<vf>.

Linux guests running under virtualization platforms such as KVM, Xen, VMware Workstation or ESX, or Microsoft Hyper-V will not have their devices renamed.

Reference-
http://fedoraproject.org/wiki/Featur...rkDeviceNaming

sudo_su · 12-25-2012, 12:21 PM

Here they are,

(1) ls -l /sys/class/net/

Quote:

total 0
lrwxrwxrwx. 1 root root 0 Dec 25 10:30 eth0 -> ../../devices/pci0000:00/0000:00:19.0/net/eth0
lrwxrwxrwx. 1 root root 0 Dec 25 10:30 lo -> ../../devices/virtual/net/lo
lrwxrwxrwx. 1 root root 0 Dec 25 10:30 virbr0 -> ../../devices/virtual/net/virbr0
lrwxrwxrwx. 1 root root 0 Dec 25 10:30 virbr0-nic -> ../../devices/virtual/net/virbr0-nic
lrwxrwxrwx. 1 root root 0 Dec 25 10:30 wlan0 -> ../../devices/pci0000:00/0000:00:1c.1/0000:10:00.0/net/wlan0

(2) ls -l /etc/udev/rules.d/

Quote:

total 64
-rw-r--r--. 1 root root 6858 Jul 19 2011 40-hplip.rules
-rw-r--r--. 1 root root 706 Jul 19 2011 56-hpmud_support.rules
-rw-r--r--. 1 root root 1652 Nov 12 2010 60-fprint-autosuspend.rules
-rw-r--r--. 1 root root 4171 Nov 11 2010 60-openct.rules
-rw-r--r--. 1 root root 1060 Nov 12 2010 60-pcmcia.rules
-rw-r--r--. 1 root root 316 Nov 5 15:21 60-raw.rules
-rw-r--r--. 1 root root 1216 Dec 25 2012 70-persistent-cd.rules
-rw-r--r--. 1 root root 590 Dec 25 2012 70-persistent-net.rules
-rw-r--r--. 1 root root 40 Dec 18 13:48 80-kvm.rules
-rw-r--r--. 1 root root 320 May 9 2012 90-alsa.rules
-rw-r--r--. 1 root root 83 Jul 19 2011 90-hal.rules
-rw-r--r--. 1 root root 53 Dec 8 2011 91-drm-modeset.rules
-rw-r--r--. 1 root root 292 Dec 10 19:53 98-kexec.rules
-rw-r--r--. 1 root root 54 Dec 8 2011 99-fuse.rules

(3) lspci|grep -i eth

Quote:

00:19.0 Ethernet controller: Intel Corporation 82566MM Gigabit Network Connection (rev 03)

(4) cat /etc/sysconfig/network-scripts/ifcfg-em1

Quote:

EVICE="em1"
BOOTPROTO="dhcp"
HWADDR="BC:30:5B

3

B:B0"
NM_CONTROLLED="yes"
ONBOOT="no"
TYPE="Ethernet"
UUID="0e1d62d9-2d16-4445-9088-155d46e7c3d5"

sudo_su · 12-25-2012, 12:23 PM

Lolz for my HWADDR that changed into smilies

sudo_su · 12-25-2012, 12:48 PM

@sharadchhetri

sorry may be i am not getting you but my question still is,

1: Why is my ifconfig showing entries for eth0?

2: How can I assign static IP to my ethernet as i dont have conf file for it in my /etc.

The onez that i got i.e ifcfg-em1, I tried on them but they are not working.

sharadchhetri · 12-25-2012, 01:08 PM

Quote:

Originally Posted by sudo_su

@sharadchhetri

sorry may be i am not getting you but my question still is,

1: Why is my ifconfig showing entries for eth0?

2: How can I assign static IP to my ethernet as i dont have conf file for it in my /etc.

The onez that i got i.e ifcfg-em1, I tried on them but they are not working.

(1) Take the backup of these files first*****And move to new directory**********
mkdir -p /root/backup
mv /etc/sysconfig/network-scripts/ifcfg-em1 /root/backup
mv /etc/udev/rules.d/70-persistent-net.rules /root/backup

(2) cp -p /etc/grub.conf /root/backup/grub.conf.bak

edit /etc/grub.conf
give "biosdevname=0" on the kernel command line (rhgb quiet biosdevname=0)

if you are not sure, paste grub.conf

Step 3:

create ifcfg-eth1 file

DEVICE="eth1"
BOOTPROTO="none"
HWADDR="paste the MAC if you are seeing in ifcfg-em1"
NM_CONTROLLED="no"
IPADDR=192........
NETMASK=255.......
GATEWAY=192.....
ONBOOT="no"
TYPE="Ethernet"

NOTE: ONBOOT="no" because we are troubleshooting here. you have to up the eth by command ifup-eth1

Restart the system

paste its output also /etc/udev/rules.d/70-persistent-net.rules