eth0 not coming up on boot / network restart

eth0 (Network Card) is not coming up while system boot / reboot / or during service network restart,

It's a reported bug for RHEL 6, Follow these steps to get up and running network connection ...

Edit "/etc/sysconfig/network-scripts/ifcfg-eth0" file, which is your defualt first NIC configuration file.

If you are using DHCP server to take IP then, edit it like this;
#vi /etc/sysconfig/network-scripts/ifcfg-eth0
ONBOOT="yes"
BOOTPROTO="dhcp"

Save & restart networking service,

#service network restart               

OR

#/etc/init.d/network restart

If you are providing manual IP then, edit it like this;

DEVICE=eth0
           IPADDR=10.10.10.10
           NETMASK=255.255.255.0
           NETWORK=10.10.10.0

GATEWAY=10.10.10.253
           ONBOOT=yes
           BOOTPROTO=none
           USERCTL=no

Save & restart networking service,



#service network restart          

     OR

#/etc/init.d/network restart



OR

 you can use simple Network Configuration tool  to configure IP's but the highlighted two lines are compulsory to add manually in the file.