given machine with C6 x86_64 (seen on C 6.6 but also before and probably still present on C6.7) only 1 interface, there is dhcp on this network (for kickstarting) but the machines have static ip's, and NO networkmanager installed contents of resolv.conf search some.domain.here nameserver x.x.x.x #dns1 nameserver y.y.y.y #dns2 change resolv.conf to: search some.newdomain.here nameserver z.z.z.z #dns3 nameserver a.a.a.a #dns4 reboot machine and the contents of resolv.conf is again: search some.domain.here nameserver x.x.x.x #dns1 nameserver y.y.y.y #dns2 change it again to: search some.newdomain.here nameserver z.z.z.z #dns3 nameserver a.a.a.a #dns4 reboot again now it stick to the last update. Already tried to set /etc/sysconfig/network-scripts/ifcfg-eth0 NM_controlled=no with no result other suggestions around the internet suggest also to set in /etc/sysconfig/network-scripts/ifcfg-eth0 usepeerdns=no have not tried this but should check if this fixes stuff. Question: can someone explain me WHY this would help if it does and if this a valid entry in /etc/sysconfig/network ? since I don't want to go over all my machines (a couple thousand) figuring out how many interfaces they have and what their names are to reconfigure that for each interface (some even suggest this should be done for lo too). See also dozens of questions like that using google: https://www.google.com/search?q=centos+6+overwrites+resolv.conf+reboot G.