CentOS 6.4 Networking Problem

Home » CentOS » CentOS 6.4 Networking Problem
CentOS 6 Comments

On this system I have two nics

If I look at the network connection There is nothing there. If I do ifconfig -a the two nics are there If I do ifup eth0 I get device doesn’t seem to be present If I do ifup eth1 the system search to determine the IP information for this device.

Do somebody have an idea to bring them up?

6 thoughts on - CentOS 6.4 Networking Problem

  • ifcfg-eth0
    ifcfg-lo ifdown ifdown-bnep ifdown-eth ifdown-ib ifdown-ippp ifdown-ipv6
    ifdown-isdn ifdown-post ifdown-ppp ifdown-routes ifdown-sit ifdown-tunnel

    ifup ifup-aliases ifup-bnep ifup-eth ifup-ib ifup-ippp ifup-ipv6
    ifip-isdn ifup-plip ifup-plusb ifup-post ifup-ppp ifup-routes ifup-sit ifup-tunnel ifup-wireless init.ipv6-global net.hotplug network-functions network.functions-ipv6

    But in /etc/networking an /etc/profiles/default it’s empty

  • The content of these two files was the same as in my 5.9 server. The system was working properly at the begining. So I don’t understant probably I made a bad modification some where.

    For now, I scrapped the 6.4 and push back to 5.9 because of a lack of time to get a better understanding of the situation.
    6.0 and up seems to be far different from 5 am I wright?

    Thank’s for your help

  • Have you verified MAC address of your two NIC’s with their respective network configuration file? Are they same? Sometime that can cause a problem.

  • Yes, they are different, but mostly in the way the device names are managed. Both essentially randomize the order of detection and the numbers each device gets, but in 5.x having the right HWADDR= and mac address in the ifcfg-eth? file was sufficient to rename the device to match the DEVICE= in the file. In 6.x the names are set according to the rules in /etc/udev/rules.d/70-persistent-net.rules (which will be recreated at reboot, possibly in a different order if you delete it after a change). The /etc/sysconfig/networking-scripts/ifcfg-xxx files have to match the DEVICE= and HWADDR= entries to work. There is also some special handling for netbios names in a weak attempt at consistency that only works on certain Dell servers.