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

Thu Oct 8 21:19:18 UTC 2009
Dave <tdbtdb+centos at gmail.com>

On Thu, Oct 8, 2009 at 9:49 AM, Spiro Harvey <spiro at knossos.net.nz> wrote:
> chkconfig for dhclient too, and see what that results.


[root@ ~]# chkconfig --list|grep  -e dh -e clie
[root@ ~]#

>
> Also, look at /etc/sysconfig/network-scripts/ifcfg-eth0.


[root at lee1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# Broadcom Corporation NetXtreme BCM5751 Gigabit Ethernet PCI Express
DEVICE=eth0
BOOTPROTO=none
HWADDR=00:18:8b:0f:ad:c2
IPADDR=1[snip]0
ONBOOT=yes
DHCP_HOSTNAME=[snip]
DNS1=1[snip]0
DNS2=1[snip].2
NM_CONTROLLED=no
SEARCH=[snip]
NETMASK=255.255.255.0
DNS3=1[snip]0
GATEWAY=1[snip]0.1
TYPE=Ethernet
USERCTL=no
PEERDNS=yes
IPV6INIT=no

>
> It's possible to have addresses "statically" assigned via DHCP based on
> MAC addresses. If resolv.conf is getting populated by dhclient, then
> I'm guessing the odds of you having a dhcp server on your network is
> good. :)

You guessed right. But the question remains, what software is writing the file?

> In all likelihood, you have a static IP assigned in your ifcfg-eth0,
> and the resolv.conf is being over-written by dhclient.

What is invoking dhclient, how do I find it?
 rpm -qR dhclient
/bin/bash
initscripts >= 6.75
libc.so.6()(64bit)
libc.so.6(GLIBC_2.2.5)(64bit)
libc.so.6(GLIBC_2.3)(64bit)
libc.so.6(GLIBC_2.3.4)(64bit)
libc.so.6(GLIBC_2.4)(64bit)
libc.so.6(GLIBC_2.8)(64bit)
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rpmlib(VersionedDependencies) <= 3.0.3-1
rtld(GNU_HASH)

Dave