In RHEL 7.x and CentOS 7.x you may see an odd extra network interface listed as “virbr0” (virtual bridge zero). This is provided as a default way to share the host physical network with private guest virtual machines. Unfortunately this interface is default assigned an IP and shows up as an active interface even when you’re not running any virtual machines.
If you’re not using the RHEL/CentOS virtualization feature, I recommend you turn off libvirtd which will get rid of this odd extra interface. This may be particularly useful to Enterprise Domain users who would like to prevent this Non-Routable IP from being registered in the organization’s DNS Infrastructure causing reachability and name resolution trouble for network users.
- systemctl disable libvirtd
- systemctl stop libvirtd
- shutdown -r now
After a reboot, the virbr0 will be gone from your system and the network configuration will be clean again. I’m not sure if there is any easy way to reload the network without rebooting – feel free to comment if you have a reliable supported way to finish this task without rebooting the system.
If you’re making use of the virtualization functionality, you can still restrict which interfaces are used for Dynamic DNS registration. Use the “dyndns_iface” option in your “sssd.conf”.