Originally Posted by sluge
I don't use DHCP, only static IP
Ah. That's going to require some detective work.
I would add a boot script that is run at every startup and shutdown level that copies /etc/resolv.conf to try and get a handle on when it is being modified. Because this may need to be done when only the / file system is mounted, I would write to the /etc/ directory rather than the obvious /tmp (unless /tmp is on / and is not emptied durin shutdown-boot). Assuming /tmp is not on / I would run cp -p /etc/resolv.conf /etc/resolv.conf.[KS]<n>
where [KS] is K for the shutdown levels and S for the startup levels and <n> is the level.