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Jonas
Asked: 2010-10-26 05:13:49 +0800 CST

New MAC-address, now I have no network-access

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I run Ubuntu Server 10.10 in VirtualBox with Windows as host. Accidently I choosed to generate a new random MAC-address for my Ubuntu machine in VirtualBox. And now when I have booted my Ubuntu with the new MAC-address, I don't get an external IP-address. I'm using DHCP to get IP-addresses.

I guess I have to run a command and inform my Ubuntu system that the MAC-address has changed to get an external IP-address.

If I execute sudo /etc/init.d/networking restart I get this message:

SIOCSIFADDR: No such device
eth0: ERROR while getting interface flags: No such device
eth0: ERROR while getting interface flags: No such device
Bind socket to interface: No such device
Failed to bring up eth0

How can I solve this?

configuration networking server

3 Answers

  1. Best Answer

    Since your mac address have changed you no longer have an interface called eth0, this name is reserved for an interface with the "old" mac-address. The "new" interface should have the next free name (eg. ethN).

    To see all the interfaces on the machine you can use this command: ifconfig -a

    If you want to reset the name reservations for network interfaces you can remove the file /etc/udev/rules.d/70-persistent-net.rules and restart the machine (or remove/insert the device, though this is not possible in this case).

    Alternatively you can change the interface-name that you have configured to what ever the new one is called by changing all occurences of the old name with the new one in the file /etc/network/interfaces

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  2. I guess you are using static IP on your ubuntu host.

    Since you have changed the MAC address, the ubuntu will create a new "eth" for you instead of using the old one.

    Modify the file /etc/sysconfig/networks/ifcfg-eth0 to ifcfg-eth1 or setup a static configuration using network manager.

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  3. First in VM Guest create a file named newfile: sudo nano /etc/init.d/newfile with two lines:

    #!/bin/bash
sudo ifup eth0

    next, from console:

    sudo chmod +x /etc/init.d/newfile
sudo chmod 755 /etc/init.d/newfile 
sudo update-rc.d newfile defaults

    I used this solution because eth0 is down after reboot with static IP (with DHCP work fine).

    my /etc/network/interfaces:

        # The loopback network interface
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.10
netmask 255.255.255.0
broadcast 192.168.1.255
gateway 192.168.1.1
nameservers 192.168.1.1

    (sorry for my english)

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