In Scientific Linux 5.5, /etc/resolv.conf is continually overwritten and so DNS is broken. If I delete or change it, it instantly reverts to its former state. Writing over it with: cp /etc/NEWresolve.conf /etc/resolv.conf && chattr +i /etc/resolv.conf just results in an immutable copy of the original resolv.conf with no changes. I'm running as root (not sudo) and Avahi and NetworkManager are not running.
Any ideas? There's no DHCP anywhere on this machine, and even if there were, I can't imagine it'd overwrite the file so quickly.
Thanks
Some ancillary info: uname -a Linux localhost.localdomain 2.6.18-238.12.1.el5 #1 SMP Tue May 31 13:12:32 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux Intel I340 (82580) NIC
NetworkManager is a likely culprit. NetworkManager will overwrite /etc/resolv.conf, and could explain the behavior you are seeing. However, I think NetworkManager typically adds a warning to the file like
# Managed by NetworkManager, do not edit.From the GUI, you can configure NetworkManager to not overwrite /etc/resolve.conf .
NetworkManager is considered harmful on many systems (Servers, virtualization hosts) because it overwrites your manual settings without warning you, and it doesn't support advanced networking features. You might want to to just shut down the service and prevent it from starting at next reboot.
and see how modifies the other files