Re: [ovirt-users] selectively disabling IPv6 on bridges

On Wed, May 06, 2015 at 01:53:35PM +0100, Dan Kenigsberg wrote: > On Wed, May 06, 2015 at 01:28:30PM +0200, Rik Theys wrote: > > Hi, > > > > I'm looking for a way to selectively disable IPv6 on the bridge interfaces > > on the oVirt hosts. > > > > When oVirt creates the bridges for all logical networks on the host, it > > keeps the default settings for IPv6 which means all bridges get a link-local > > address and accept router advertisements. > > > > When a VM is created on the logical network, it can now reach the host over > > IPv6 (but not over IPv4 if no IP address has been assigned on the host). If > > it sends out a router advertisement it can even create a global IPv6 address > > (haven't tested this). > > > > How can I prevent this? > > > > I would like to prevent the guest from IPv6 access to the host but the guest > > itself still needs IPv6 access (global IPv6 addresses). > > > > Is it sufficient to create a sysctl config file that says: > > > > net.ipv6.conf.default.disable_ipv6 = 1 > > Yes, I believe that this would do the trick. For any newly-created > device on the system, regardless of ovirt bridges. > > I now see that el7 has changed the default for IPV6INIT to "yes". We > should be more prudent and set IPV6INIT=no on all our devices. Lukáš, it seems that setting IPV6INIT=no is not enough: IPV6INIT=yes|no Enable or disable IPv6 static, DHCP, or autoconf configuration for this interface Default: yes The bridge still gets a link-local ipv6 address anyway. Is there an initscript means to disable this completely, or should we resort to /proc/sys/net/ipv6/conf/<bridge-name>/disable_ipv6 ? Dan.