Internet Connection Problem

vamski · Post by **vamski** » 2006/10/16 00:38:49

Hi Guys!

I am new to linux and networking stuff and I am having issues with setup internet. Here is my setup

I use static ip's for my oracle database testing.

I have to Linux boxes installed with Cent OS Linux 4.2

Server 1 (linux1)
Device IP Address Subnet Gateway Purpose
eth0 192.168.1.100 255.255.255.0 192.168.2.1 Connects linux1 to the public network
eth1 192.168.2.100 255.255.255.0 Connects linux1 (interconnect) to linux2 (linux2-priv)

Server 2 (linux2)
Device IP Address Subnet Gateway Purpose
eth0 192.168.1.101 255.255.255.0 192.168.2.1 Connects linux2 to the public network
eth1 192.168.2.101 255.255.255.0 Connects linux2 (interconnect) to linux1 (linux1-priv)

my router ip is 192.168.2.1

bothe eth1' s are connected to a linksys switch.

I have connected both the eth0's on linux 1 and Linux2 to my router.

I can see the router ip as the dafault gateway when issues route -n command.

when i open a browser and i get an error message " page can not be found"

What else need to be done for accessing internet from my linux boxes.

i can connect to internet thru windows xp machine which is connected to the same router.

You can get more details about my system configuration at http://www.oracle.com/technology/pub/articles/hunter_rac10gr2.html

Any one's help is appreciated!

Thanks,
Vamski.

Post by **arrfab** » 2006/10/16 07:34:25

If you can ping your router from both server1 and server2 and that your default gw on both machines is the router, what about dns servers ?
What's the content of /etc/resolv.conf ?

gerald_clark · Post by **gerald_clark** » 2006/10/16 13:42:46

Your ETH1's are on 192.168.2.
Your Router is on 192.168.2, but you have your router connected to eth0.
Connect your router to eth1. That is where your 192.168.2 traffic is going.

I fail to see why you have 2 interfaces on your machines.

vamski · Post by **vamski** » 2006/10/16 19:19:59

I tried connecting the router to eth1 's on both machines.. Now I can ping the router as all of them are in same subnet 192.168.2.*
But still not able to connect to internet.. Do i need to configure DNS for accessign internet from Linux?

My router is configured with DHCP. SO when I connect from windows XP to the router it will get the IP assigned automatically. 192.168.2.150-250 is the range configured in my router for DHCP. But the Linux machines are using static IP's assigned by me which are no in that DHCP range of the router. is this a problem?

Why I am using two NIC's is for my Oracle RAC implementation testing. One pair for Public n/w and second pair is for private interconnect.

gerald_clark · Post by **gerald_clark** » 2006/10/16 19:26:25

You need to edit /etc/resolv.conf
add a line:
nameserver=xxx.xxx.xxx.xxx

where xxx.xxx.xxx.xxx is the ipaddress of the nameserver your ISP provides.
You can have 3 nameservers in your /etc/resolv.conf file.

andersod · Post by **andersod** » 2006/10/16 19:56:30

I am having a DNS resolution problem on my home DSL network (3 PCs). I have 2 Windows machines. In fact, the problem machine has Windows on the main drive and works when booted to Windows. I keep CentOS on a removable drive and use a Linux boot disk. All machines on my home network have DNS resolution in Windows, but not in Linux. Linux is acquiring the correct DNS servers via DHCP. I can ping them. I can browse the internet via IP address or 'host' entries. Resolv.conf has the correct settings. I use Qwest for DSL and ISP. Their support group had no solutions for me. I bypassed my switch and plugged straight into the router - no help. Even my Linux teacher at a local community college is stumped. Any ideas? Thank you.

garskoci · Post by **garskoci** » 2006/10/16 21:27:43

andersod - you should start a new thread for this. Don't hyjack others. When you do, verify that your gateway definition is correct. Post your resolv.conf file and the output of netstat -r.

vamski · Post by **vamski** » 2006/10/17 05:12:44

Gerald..

I got the DNS info about my ISP and put that in /etc/resolv.conf.. it works great and I can connect to the internet now..i appreciate you help and support.

Is there way I can acheive the same for the other NIC also. I mean 192.168.1.100 ...using this i can't ping the router..

its working fine from 192.168.2.100

Thanks,
Vamski

gerald_clark · Post by **gerald_clark** » 2006/10/17 13:11:22

Your router has to be on the same logical network as the interface to which it is connected.
They must both be on 192.168.1 or 192.168.2, or you must change the netmask on all devices
so the network includes both subnets.
That would be 255.255.252.0.
You could use an easier 255.255.0.0.
This would make your network 192.168.0.0

Oocean · Post by **Oocean** » 2008/04/28 03:01:01

Vamsi,

I am following the same doc from Jeffrey Hunter to create the RAC. Rac is successfully setup and working fine. But I am not able to ping the router from the linux servers. Even the other pc in the network cannot ping the linux servers.

Could you please advice what needs to be done .

CentOS