One for the Gods Of Linux :) In need of help (Centos / Redhat)

ally_uk

Hi guys I am having some trouble with getting DNS to work. I will walk you through what I have done so far.

1) Clean Installed Centos
2) Disabled the Network Manager Service
3) Edited /etc/sysconfig/network-scripts/ifcfg-lo (For some reason there isn't a ifcfg-0 or 1 config file?)
4) added the following information

DEVICE=eth0
BOOTPROTO=static
IPADDR=192.168.168.222
NETMASK=255.255.255.0
ONBOOT=yes
TYPE=Ethernet

(Restarted the network service) service network restart

5) added the gateway

nano /etc/sysconfig/network

Networking=yes
Hostname= Akira
Gateway= 192.168.1.254

( Restarted network service again)

I can ping the router fine

6) Add DNS Details

nano /etc/resolv.conf

nameserver 192.168.1.201

( I also have tried with various other servers such as 8.8.8.8. )

Restart network

Now whenever I try to ping a web address I get Unknown Host. I have read numerous other guides and I am stumped and really need
your help.

Many Thanks

demonfurbie

on the hosts im assuming that you have cleared the dns cashe

Roguetadhg

How do you like CentOS? I've heard good things about it.

jibbajabba

3) Edited /etc/sysconfig/network-scripts/ifcfg-lo (For some reason there isn't a ifcfg-0 or 1 config file?)

You don't configure the ifcfg-lo file - in fact, leave it as is as it is the loopback adapter, here an example

DEVICE=lo
IPADDR=127.0.0.1
NETMASK=255.0.0.0
NETWORK=127.0.0.0
# If you're having problems with gated making 127.0.0.0/8 a martian,
# you can change this to something else (255.255.255.255, for example)
BROADCAST=127.255.255.255
ONBOOT=yes
NAME=loopback

What you need is the file with the same name as your interface.

So, if your interface is eth0, you go with ifcfg-eth0

For example

DEVICE=eth0
BOOTPROTO=static
BROADCAST=192.168.168.255
IPADDR=192.168.168.222
NETMASK=255.255.255.0
NETWORK=192.168.168.0
ONBOOT=yes

ally_uk

Thanks I shall give this a go and let you know what happens

it_consultant

ally_uk wrote: »

Hi guys I am having some trouble with getting DNS to work. I will walk you through what I have done so far.

1) Clean Installed Centos
2) Disabled the Network Manager Service
3) Edited /etc/sysconfig/network-scripts/ifcfg-lo (For some reason there isn't a ifcfg-0 or 1 config file?)
4) added the following information

DEVICE=eth0
BOOTPROTO=static
IPADDR=192.168.168.222
NETMASK=255.255.255.0
ONBOOT=yes
TYPE=Ethernet

(Restarted the network service) service network restart

5) added the gateway

nano /etc/sysconfig/network

Networking=yes
Hostname= Akira
Gateway= 192.168.1.254

( Restarted network service again)

I can ping the router fine

6) Add DNS Details

nano /etc/resolv.conf

nameserver 192.168.1.201

( I also have tried with various other servers such as 8.8.8.8. )

Restart network

Now whenever I try to ping a web address I get Unknown Host. I have read numerous other guides and I am stumped and really need
your help.

Many Thanks

Every time I install the tiny Centos version (you know, the 400 MB one) I have to open my "Linux for Dummies" book to remind me how to configure the darned interface.

ChooseLife

ally_uk wrote: »

whenever I try to ping a web address I get Unknown Host.

First things first:

1. ping 192.168.1.201
2. dig @192.168.1.201 www.google.com[U][/U]
3. dig www.google.com

What do you get for each of those?

demonfurbie

i gave up the light version of centos and just now use clearos (centos with a web based config)

if i have to use centos i install every damn thing so i dont have to worry about it later, its alot easier to turn off unneeded things off than install/config later

dead_p00l

Roguetadhg wrote: »

How do you like CentOS? I've heard good things about it.

It's Redhat without the Redhat. After years of using debian it took a little getting used to but it's not bad at all.

dontstop

Yes, after re-reading. Check that DNS is actually responding to your queries

Have you tried to ping 8.8.8.8?

ally_uk

Ok started with a clean install, Disabled network manager

Performed a ifconfig -a which told me my ethernet adapter is eth-0


I then went to network-scripts and created a ifcfg-eth0 file

DEVICE=ETH0
BOOTPROTO=STATIC
BROADCAST=192.168.1.255
IPADDR=192.168.1.205
NETMASK=255.255.255.0
NETWORK=192.168.1.0
ONBOOT=YES

Now when I run service network I am being greeted with a Device ETH0 does not seem to be present?

Now I am really confused

jibbajabba

unless it is a copy / paste error, make sure it's lowercase (eth0 not ETH0 in the config file).

ally_uk

All sorted

/etc/sysconfig/network-scripts



DEVICE=eth0
BOOTPRO=STATIC
IPADDR=192.168.1.5
NETMASK=255.255.255.0
ONBOOT=YES
DNS1=192.168.1.1
DNS2=8.8.8.8

Can ping router, and other machines and am wiriting this message from Akira which is my Centos Server so now have a Static I.P didn't have to edit resolv.conf though.

ally_uk

Got another interesting issue, I have another Centos Box at work I have setup the static I.P address and DNS as above.

I can ping the gateway fine from the Centos box, I can Ping Google and the dns server by I.P address. When I run dig google.com it produces results and yum-update enabled me to update the system. So DNS is working fine.

The snag I am now having is I cannot ping another host or I have another host when DHCP was enabled on the Centos box I could ping between both and could access the Centos machine via SSH. Firewall has been configured on the host machine to accept ICMP

IP details are correct and the gateway is set correct.

further troubleshooting check route?

ifcfg-eth0

DEVICE=eth0
BootPRO=Static
IPADDR=192.168.1.255
NETMASK=255.255.255.0
GATEWAY=192.168.1.254
ONBOOT=YES
DNS1=192.168.1.200
DNS2=8.8.8.8


/etc/sysconfig/network

NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=AKIRA
GATEWAY=192.168.1.254

results of route

Destination gateway Genmask flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 V 0 0 eth0
link-local * 255.0.0 V 1002 0 eth0
default my.router VG 0 eth0

demonfurbie

umm ya sure the ip is good ... last i checked .255 was reserved

ally_uk

Changed I.P address, and temporarily disabled Windows Firewall seems like I have to add allow ICMP echo on the Windows Firewall to allow Ping Requests before could only ping one way from the Windows Host to server any Ping request leaving the Linux side would get blocked by the firewall.

Issue resolved good learning process though

jibbajabba

ally_uk wrote: »

good learning process though

Problems are the best way to learn, that's for sure