1, change the root password,

in the startup process, when in menu selection interface, press 'e' to enter the edit the command line, at the end of the command line add space and '1', press enter, subsequently will enter to the single user mode, use 'runlevel' command to check whether it is in single user mode. make sure the selinux set as permissive, 

setenforce 0
getenforce


and change the root password 

passwd


then reboot


2, setup the network

use the setup utility to setup the eth0 network, static IP as 192.168.0.10x (10x = 100 + x, eg, 103 = 100 + 3), netmask as 255.255.255.0, gateway as: 192.168.0.254, DNS server as: 192.168.0.254, Hostname as: serverx.example.com (x is the same as 10x)


Stop and block NetworkManager, as NetworkManager might be unstable, 

/etc/init.d/NetworkManager stop
chkconfig NetworkManager off


edit configuration file: /etc/sysconfig/network-scripts/ifcfg-eth0

tell the system not to look for the DNS information of the NetworkManager

set 'PEERDNS=NO'

set ONBOOT as yes,

'ONBOOT=yes'


3, make sure can dig 'instructor.example.com'

ping server3.example.com
host server3.example.com
ping instructor.example.com
dig instructor.example.com