[CentOS] resolv.conf rewritten every reboot. How to figure out who and why?

>Just one of those things you kind of pick up as you go along and
>remember.  Tribal knowledge if you will.

There's two pdf's and one command I use "often" :)

The redhat 5.3 deployment and installation pdf's (or the online versions)
and:

# find /usr/share/doc/ -exec grep "PEERDNS" '{}' \; -print
    PEERDNS=yes|no
      file if PEERDNS is not set to "no".
/usr/share/doc/initscripts-8.45.25/sysconfig.txt
    honor PEERDNS=no for pump and dhcpcd too (#18619)
    DEFROUTE defaults on; PEERDNS documented and defaults on
/usr/share/doc/initscripts-8.45.25/ChangeLog

Now you know what doc to read...

Also:
man -K PEERDNS
But that's generally a slow and last ditch effort even after google:)
It also never helped with this string but its useful to know.