DNS entry vanishes after restart

sudo_su · 12-21-2012, 04:49 AM

Dear experts,

I had configured my system for static IP, GATEWAY and DNS. I put gateway entry in;

"/ets/sysconfig/network.conf"

and DNS entry in;

"/etc/resolve.conf"

"ifcfg-em1" only contains my IP and subnet mask.

the problem is that my system resolves names properly but everytime it restarts, ,my nameserver entry from resolve.conf is removed and I need to re-enter my dns entry which sounds weird.

Quote:

[root@localhost ~]# vi /etc/resolv.conf
# Generated by NetworkManager

# No nameservers found; try putting DNS servers into your
# ifcfg files in /etc/sysconfig/network-scripts like so:
#
# DNS1=xxx.xxx.xxx.xxx
# DNS2=xxx.xxx.xxx.xxx
# DOMAIN=lab.foo.com bar.foo.com
~

~
~
"/etc/resolv.conf" 9L, 228C

how to overcome this issue, please.

markush · 12-21-2012, 04:54 AM

Which dhcp client does your system use? When you use dhcpcd with a static IP, you will have to add "nohook.resolv.conf" to the /etc/dhcpcd.conf file.
When you use another dhcp client, read the manpage.

Markus

sudo_su · 12-21-2012, 05:00 AM

Brother,

how would i find that out :S

I am using CentOS.

markush · 12-21-2012, 05:05 AM

Execute

Code:

apropos dhcp

find out if dhcpcd is installed and if it's not find out which program is used instead.
Afterwards read it's manpage.

Markus

bradvan · 12-21-2012, 05:05 AM

If you are using static ips, disable network manager.

sudo_su · 12-21-2012, 05:09 AM

Quote:

Originally Posted by markush

Execute

Code:

apropos dhcp

find out if dhcpcd is installed and if it's not find out which program is used instead.
Afterwards read it's manpage.

Markus

That is what I get;

Quote:

[root@localhost ~]# apropos dhcp
dhclient-script (8) - DHCP client network configuration script
dhclient.conf [dhclient] (5) - DHCP client configuration file
dhclient.leases [dhclient] (5) - DHCP client lease database
dhcp-eval (5) - ISC DHCP conditional evaluation
dhcp-options (5) - Dynamic Host Configuration Protocol options
dhcpc_selinux (8) - Security Enhanced Linux Policy for the dhcpc processes
dhcpd_selinux (8) - Security Enhanced Linux Policy for the dhcpd processes
dnsmasq (8) - A lightweight DHCP and caching DNS server
kpac_dhcp_helper (7) - provides Proxy Auto Configuration to KDE

sudo_su · 12-21-2012, 05:11 AM

Quote:

Originally Posted by bradvan

If you are using static ips, disable network manager.

brother from where I am gona disable it?

markush · 12-21-2012, 05:12 AM

Well it's dhclient, read the manpage for dhclient and dhclient.conf

Markus

markush · 12-21-2012, 05:15 AM

Quote:

Originally Posted by sudo_su

brother from where I am gona disable it?

Well, this depends on your distribution, I would google for "centos static ip" or "centos networkmanager" ...... and find this http://www.centos.org/docs/5/html/De...nterfaces.html

Markus

bradvan · 01-04-2013, 05:41 AM

Sorry, I was away for the Christmas break.

First, cd /etc/sysconfig/network-scripts then:

Code:

for f in ifcfg-eth?; do
   if [ $(grep -c 'NM_CONTROLLED="yes"' ${f}) -gt 0 ]; then
      echo "Modifying the ${f} script to disable network manager."
      sed -i 's/^\(NM_CONTROLLED="\)yes.*/\1no"/' ${f}
   fi
   if [ $(grep -c "^DNS" ${f}) -gt 0 ]; then
      echo "Deleting the dns resolver entries from ${f}."
      sed -i '/^DNS/d' ${f}
   fi
done

Make sure your /etc/resolv.conf is set up correctly. Then do:

Code:

rpm -e NetworkManager-gnome NetworkManager-glib NetworkManager

That should get rid of Network Manager.

chrism01 · 01-06-2013, 08:07 PM

If you just want to disable it on a per NIC basis

Code:

cat /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE="eth0"
HWADDR="E0:CB:4E:B9:5F:1A"
NM_CONTROLLED="no"
ONBOOT="yes"
BOOTPROTO="dhcp"