Linux changing DNS search order
Under Linux you need to use /etc/nsswitch.conf file which is used by system databases and Name Service Switch configuration file
edit /etc/nsswitch.conf
Open /etc/nsswitch.conf file using text editor:
vi /etc/nsswitch.conf
Look for hosts:
hosts: files dns wins mdns4_minimal [NOTFOUND=return]
Set above order as per your requirement. Close and save the file.