CentOS: eth0 not starting on boot

Solution 1:

Hmm. From your last message, look for the /etc/sysconfig/network file.

I have:

$ cat /etc/sysconfig/network
NETWORKING=yes

You can also have (on my CentOS 5 box):

NETWORKING=yes
HOSTNAME=foo.example.org
GATEWAY=192.168.1.1

Documentation is here (at least for 5, which should be very similar)

I'm not sure what the default is for the "NETWORKING" setting. It's possible it's "no" and that's why it's not starting on boot.

Solution 2:

Open /etc/sysconfig/network-scripts/ifcfg-eth0 file and replace line

ONBOOT=no

with

ONBOOT=yes

save and exit the file, and restart the linux system.

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Solution 3:

Disable the NetworkManager service with chkconfig or ntsysv and see if that helps.

If it's not running, check your /var/log/boot.log, dmesg and /var/log/messages. Following a clean boot, grep eth0 /var/log/messages or dmesg | grep eth0 should give you an idea of what's happening.

Is this a new VM or a cloned system (P2V)?