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

Dan Kenigsberg píše v Čt 07. 05. 2015 v 11:46 +0100: > 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. You should disable this in kernel. IPV6INIT=no basically means that network-scripts will not touch it. But kernel will setup the link-local address.

I think you also have to disable this on the physical interface that's part of the bridge to fully disable this?