Red Hat / CentOS Linux: Explain Use of Network Interface virbr0

Posted on in Categories , , , , , , last updated July 29, 2008

Q. I’ve installed Red Hat Enterprise Linux 5.2 and I see virbr0 network interface along with my eth0 interface? What it is? How do I disable or remove virbr0?

A. virbr0 is xen interface used by Virtualization guest and host oses for network communication. Following are the packages under Red Hat / CentOS Linux:
Group: Virtualization
Description: Virtualization Support.
Mandatory Packages:
=> xen
=> kernel-xen
Default Packages:
=> virt-manager
=> Virtualization-en-US
=> gnome-applet-vm
=> libvirt
You can disable virbr0 if you don’t need xen Virtualization support, enter:
# yum groupremove "Virtualization"
Sample output:

Loading "rhnplugin" plugin
Loading "security" plugin
Setting up Group Process
rhel-x86_64-server-vt-5   100% |=========================| 1.4 kB    00:00     
rhn-tools-rhel-x86_64-ser 100% |=========================| 1.2 kB    00:00     
rhel-x86_64-server-5      100% |=========================| 1.4 kB    00:00     
No package matched to remove
No package matched to remove
No package matched to remove
No package matched to remove
No package matched to remove
Resolving Dependencies
--> Running transaction check
---> Package libvirt.x86_64 0:0.3.3-7.el5 set to be erased
--> Processing Dependency: libvirt.so.0()(64bit) for package: libvirt-python
--> Processing Dependency: libvirt = 0.3.3 for package: libvirt-python
--> Running transaction check
---> Package libvirt-python.x86_64 0:0.3.3-7.el5 set to be erased
--> Processing Dependency: libvirt-python for package: rhn-virtualization-host
--> Running transaction check
---> Package rhn-virtualization-host.noarch 0:1.0.1-55 set to be erased
--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size 
=============================================================================
Removing:
 libvirt                 x86_64     0.3.3-7.el5      installed         3.4 M
Removing for dependencies:
 libvirt-python          x86_64     0.3.3-7.el5      installed         230 k
 rhn-virtualization-host  noarch     1.0.1-55         installed         155 k

Transaction Summary
=============================================================================
Install      0 Package(s)         
Update       0 Package(s)         
Remove       3 Package(s)         

Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing   : libvirt-python               ######################### [1/3] 
  Erasing   : rhn-virtualization-host      ######################### [2/3] 
Stopping crond: [  OK  ]
Starting crond: [  OK  ]
  Erasing   : libvirt                      ######################### [3/3] 

Removed: libvirt.x86_64 0:0.3.3-7.el5
Dependency Removed: libvirt-python.x86_64 0:0.3.3-7.el5 rhn-virtualization-host.noarch 0:1.0.1-55
Complete!

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

18 comment

  1. if i give the Command in Redhat Linux 5.1 means it shows

    “Loading “rhnplugin” plugin
    Loading “Security” plugin
    Loading “installonlyn” plugin
    This system is not regestered with RHN
    RHN support will be disable
    Setting up group process
    Setting up repositories
    No repositories available to set up
    No group named virtualization exists
    No packages to remove from groups”

    it shows the above message, but if i run the command
    “ifconfig”
    it shows the following groups

    eth0
    lo
    peth0
    vifo.0
    virbro
    xenbro

    how could i remove these groups except eth0 & lo?

  2. I got the same results as what you got when I ran, # yum groupremove “Virtualization”
    My guess is that “Virtualization” was never used or actually created. This is what I did to uninstall virbr0.

    # yum remove rhn-virtualization-host
    # yum remove libvirt-python
    # yum remove libvirt
    # ifconfig

    Everything should be gone except for eth0 & lo.

  3. This is for RHEL 5.3 32 bit.

    I had run yum groupremove “Virtualization” with the same unhappy results as SSG
    above. The virbr0 address was hurting my Director Server.

    rpm -e –nodeps libvirt seems to work. Ifconfig shows eth0 and l0 only.

  4. I have Fedora 10 and i want to disable virbro.
    yum groupremove “Virtualization” dont work.

    I solved the problem with rpm -e -nodeps libvirt.

  5. I tried the above and it removed everything with the first command, but virbr0 is still there. Ran the others and it says the software is not installed. May be a reboot? Can’t do it yet as it’s a production computer.

  6. Sir, I have a problem. I have installed RHEL 5.1 in both my Laptop and on Desktop. In desktop it is working fine but in Laptop I am not able to connect to the internet.

    When I use ifconfig it shows virbr0 interface and lo interface.

    There is no eth0…

    I tried fedora 12 and ubuntu too but same thing is happening. In desktop it is working fine. Is there is something related to my laptop’s lan card?

    My system configuration is—

    Sony vaio ( E series ) , 3 GB RAM, 320 HDD, INTEL CORE i3,

    1. Sir,
      please let me know how you install the linux becoz i m facing the problem while installing in my sony E series laptop.

    2. Try ifconfig -a and if you then see (unconfigured) eth0 interface, then you have only non-configured ethernet adapter.
      itconfig eth0 netmask up
      route add -net default gw
      will help (or starting dhcpcd if you have DHCP server in your network).

      If you don’t see eth0 after ifconfig -a then your ethernet card was not recognized by the system. modprobe could help, but imho you will have to find kernel patch for your ethernet device and recompile kernel. I had to do this for my AsRock motherboard because of Atheros ethernet card. (Atheros produces most weird hardware in the world. Sony takes second place…)

  7. Sir,
    I m not able to install the Linux On my sony viao laptop Model EB34 and i don,t want to install virtually. Please tell me the reason for the above mentioned problem

  8. @Ashish : I’m facing the same problem. It was installed correctly but networking is not enabled.

  9. Can anyone please tell me where is the configuration file of virtual bridge virbr0 in Linux. Or how can i change the address for Virbr0.

    Thanx in advance. :-)

  10. I had similar problems under Fedora 16 until I removed a package called “bridge-utils”. The virbr0 interface immediately disappeared – didn’t even need to stop the network.

  11. I also had to remove:
    yum remove rhn-virtualization-common
    yum remove bridge-utils

    Followed by a reboot.

  12. For those looking not to remove virbr0 but to configure it (e.g. to use xen or kvm virtualization), a look into /etc/libvirt is recommended.

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