[SOLVED] No internet connection with Optiplex running CentOS 6

michaelk · 01-24-2016, 06:31 AM

Post the /etc/sysconfig/network-scripts/ifcfg-eth0 file

Try the following for assigning an IP address via ifconfig.

ifconfig eth0 192.168.0.212 netmask 255.255.255.0 up

localhost i.e. 127.0.0.1 is a virtual interface and therefore pinging it does not use any real hardware.

ZZII · 01-24-2016, 06:51 AM

Code:

DEVICE=eth0
HWADDR=b8:ac:6f:1c:46:38
TYPE=Ethernet
UUID=6fa5aa0d-234e-4f12-a590-ef8c7f12209d
ONBOOT=no
NM_CONTROLLED=yes
BOOTPROTO=none
USERCTL=no
IPV6INIT=no
DNS1=(the DNS that my desktop reports)
DNS2=8.8.8.8     <-- I don't know why this is still here I tried to clear it in system-config-network
IPADDR=192.168.0.121
NETMASK=255.255.255.0
GATEWAY=192.168.0.1

Okay, so I tried that ifconfig string and it succeeded. "route" worked too, but had no default destination. The ping of localhost was successful. But google.com gave unknown host.

Also by the way, I have a wireless repeater going into a router then to the Optiplex if that makes a difference. Is gateway the router IP, the repeater, or the IP of the modem the repeater gets it's signal from?

michaelk · 01-24-2016, 07:05 AM

ONBOOT=no
should be changed to
ONBOOT=yes

The gateway address should be the LAN IP address of the router if I understand your setup.

ZZII · 01-24-2016, 03:36 PM

Yeah, I'll change ONBOOT.

The setup goes:

Code:

     MODEM
       |
Wireless repeater
       |
     Router
       |
     --------
    |        |
 Desktop  Optiplex
 (Mint)   (CentOS)

There is a reason to this, and some some unimportant devices are omitted.

The router IP is what I am using as gateway (192.168.0.1)

I changed ONBOOT and now it activates on boot, and even shows the inet, bcast and netmask in ifconfig now. But ping google.com still gives unknown host.

michaelk · 01-24-2016, 05:18 PM

Can you ping google's IP address?

ping 216.58.219.78

ZZII · 01-24-2016, 07:35 PM

Quote:

Originally Posted by michaelk

Can you ping google's IP address?

ping 216.58.219.78

Indeed I can.

michaelk · 01-24-2016, 08:04 PM

Good, so this is just a DNS problem.

So post the contents of your /etc/resolv.conf file.

If it does not contain the DNS servers then you can set NM_CONTROLLED=no and add the DNS servers to /etc/resolv.conf

ZZII · 01-24-2016, 08:57 PM

It has "nameserver (the IP)"

(Can I post my DNS? I've seen people sensor their's)

michaelk · 01-24-2016, 09:05 PM

Sure.

ZZII · 01-24-2016, 09:10 PM

/etc/resolv.conf =

Code:

nameserver 127.0.1.1

michaelk · 01-24-2016, 09:17 PM

127.0.1.1 is another IP address for a local loopback device which is why you can not ping a name. Change that to:
nameserver 8.8.8.8

And hopefully that will work.

ZZII · 01-24-2016, 09:21 PM

Quote:

Originally Posted by michaelk

127.0.1.1 is another IP address for a local loopback device which is why you can not ping a name. Change that to:
nameserver 8.8.8.8

And hopefully that will work.

Oh. I just though it was the correct DNS because that's what my desktop has for it's.

Well there you go, it was that simple. Thank you very much. It pings now.