Network problem after upgrading from CentOS6.4 to CentOS6.6

[Vahraba]

Hello all,


I just made an upgrade from CentOS6.4 to CentOS 6.6 using the command yum upgrade. But after a reboot, I am not able to ping google or even my gateway (Destination host unreachable).
CentOS is installed on a HYPER-V virtual machine (WINDOWS SERVER 2008 R2).


Here below, find my configurations :

# vim /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE="eth0"
NM_CONTROLLED="yes"
ONBOOT=yes
HWADDR=A4:BA:DB:37:F1:04
TYPE=Ethernet
BOOTPROTO=none
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
IPADDR=192.168.2.24
NETMASK=255.255.255.0

# vim /etc/resolv.conf

; generated by /sbin/dhclient-script
nameserver 8.8.8.8
nameserver 8.8.4.4

# vim /sysconfig/network

NETWORKING=yes
HOSTNAME=VM
GATEWAY=192.168.2.1


Could you please help me ?

Thanks in advance,

[Nadeem]

Hi

I'm not sure if i'm plagued by same issue, but i'm on centos 6.6 no hyper machine direct on bare metal and i have similar DNS resolution issue can't ping anything or run any updates or installs

A few times ISP got it working somehow and no one know how and then on reboot get exact same issue. All Firewalls have been disabled etc and still does not work.

I know this does not help original poster but maybe there is a issue someone knows about that could help us both

[MarkAnthony]

I've got the same issue from 6.5 to 6.6 and have been hunting for an answer.
I've found that running yum attempts to connect to the internet... it checks the mirrors
Gets a list of applications to install/update and fails as it can't resolve DNS names for the mirror sites
So I thought IPv6 is kinda working?

Yet it can't resolve Google's IPv6 DNS

[poky]

This is my /etc/resolv.conf file (CentOS6.6):

Code: Select all

nameserver 8.8.4.4
nameserver 193.29.206.206
options single-request-reopen
options rotate
options timeout:1

[gerald_clark]

Can you ping 8.8.4.4 ?
If not you have a routing problem, or no IPV4 address.
Did you read the FAQ? http://wiki.centos.org/FAQ/CentOS6

[MarkAnthony]

Mine is similar, but its not that its like the whole IP stack is broken.

ifconfig shows no ipv4 address in my case.
Even though its static and worked in 6.5
I've set eth0 to DHCP and it receives no address...
I'm very sure it did and would have it was still 6.5

[gerald_clark]

Did you by chance install ethernet drivers from the manufacturer?
If so, you need to get them from elrepo instead so they will survive an update

[MarkAnthony]

No, I didn't
The nic drivers are the default ones 6.5 detected and installed
Couldn't tell what they are originally
My install is a hyper-v session like the original poster; so the driver, at the moment, is hv_netvsc version 3.1

If I need to update the nic driver; how do I downgrade back to 6.5, (if its possible now), to update the nic before doing a 'yum update'?

[gerald_clark]

Can't you just define it as an intel ethernet controller in the VM config file?

[MarkAnthony]

I don't believe so, I'm know VMWare better than Hyper V and that can be done in VMWare.... there is no option in the GUI in this version of Hyper-V to change the type of nic.
However I will search the net for a 'workaround'

I've had Centos 7 running on a test Hyper-V server. Not sure what version of the nic was installed there, but maybe it can be transplanted?