[CentOS] inconsistent DNS results - ping vs dig vs nslookup
Robert Henrichs
centos at henrichs.biz
Wed Jun 22 20:30:18 UTC 2011
Thanks All,
Answering multiple questions:
***
I started off with Google's DNS servers- 8.8.8.8 and 8.8.4.4 with
the same results. The current set were copied off other working
wkstas on the LAN . Same type results with "ping www.yahoo.com" and
"ping www.yahoo.com". Just changed it to: (1) 8.8.4.4 (2)
216.146.36.36 (3) 8.8.8.8
Rebooted the box, then . . .
root at pbx:~ $ cat /etc/resolv.conf
search isp.com
nameserver 8.8.4.4
nameserver 216.146.36.36
nameserver 8.8.8.8
root at pbx:~ $ ping www.henrichs.org
ping: unknown host www.henrichs.org
root at pbx:~ $ ping www.yahoo.com
ping: unknown host www.yahoo.com
root at pbx:~ $ ping yahoo.com
ping: unknown host yahoo.com
root at pbx:~ $ ping microsoft.com
ping: unknown host microsoft.com
root at pbx:~ $ ping lilug.org
ping: unknown host lilug.org
root at pbx:~ $ ping centos.org
ping: unknown host centos.org
root at pbx:~ $
what's a good link to read about how the resolv.conf file is
constructed? esp. the "search" entry?
***
This was part of the wget response:
www.henrichs.org canonical name = ehost-services119.com.
Name: ehost-services119.com
Address: 69.64.155.165
Doesn't the "address: Address: 69.64.155.165" indicate a correct result?
***
My nsswitch.conf file does contain:
hosts: files dns
(this is an interesting file I'll have to revisit...thanks).
***
It was suggested off-list that I show "the contents of
/etc/resolv.conf and a little history on your ifcfg-ethx files in
/etc/sysconfig/network-scripts/"
Here is /etc/resolv.conf:
root at pbx:/etc/sysconfig/network-scripts $ cat /etc/resolv.conf
search isp.com
nameserver 216.146.35.35
nameserver 216.146.36.36
nameserver 8.8.8.8
root at pbx:/etc/sysconfig/network-scripts $
Here are the files in my /etc/sysconfig/network-scripts directory:
root at pbx:/etc/sysconfig/network-scripts $ ls
ifcfg-eth0 ifdown-ippp ifdown-ppp ifup ifup-ib
ifup-isdn ifup-routes init.ipv6-global
ifcfg-lo ifdown-ipsec ifdown-routes ifup-aliases ifup-ippp
ifup-plip ifup-sit net.hotplug
ifdown ifdown-ipv6 ifdown-sit ifup-bnep ifup-ipsec
ifup-plusb ifup-sl network-functions
ifdown-bnep ifdown-isdn ifdown-sl ifup-eth ifup-ipv6
ifup-post ifup-tunnel network-functions-ipv6
ifdown-eth ifdown-post ifdown-tunnel ifup-hdlc ifup-ipx
ifup-ppp ifup-wireless
root at pbx:/etc/sysconfig/network-scripts $
Here is the contents of the ifcfg-eth0 file:
root at pbx:/etc/sysconfig/network-scripts $ cat ifcfg-eth0
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth0
TYPE=ethernet
BOOTPROTO=none
BROADCAST=192.168.70.255
IPADDR=192.168.70.40
NETMASK=255.255.255.0
GATEWAY=192.168.70.2
HWADDR=00:1D:7D:26:31:D0
ONBOOT=yes
DHCP_HOSTNAME=pbx.local
root at pbx:/etc/sysconfig/network-scripts $
Robert Henrichs.
At 12:42 PM 6/22/2011, you wrote:
>robert henrichs wrote:
> > I am getting what I believe to be inconsistent replies/results from
> > my CentOs machine, trying to ping URLs. Pinging by URL fails the DNS
> > lookup, while pinging the IP address (that should have been returned)
> > works. The DNS lookup also fails NSLOOKUP, but interestingly, dig
> > and wget return A records with the correct IP.
> >
> > Robert Henrichs.
> >
>wget has *not* returned correct IP! Only nslookup and dig.
>
>First try to use only google DNS servers: 8.8.8.8 and 8.8.4.4, and if
>that does not help, and your only problem is with only that domain, you
>will have to contact support where domain is parked, and see is that helps.
>
>Only relevant info is in resolve.conf, there is no need to look at
>network configuration if you can ping IP's.
>
>Ljubomir
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