Note: This question is still unresolved – the answer was auto-accepted.
I have a Debian Lenny VPS, that's running virtualized by Parallels/Virtuozzo. Currently, the network interface doesn't have an IPv6 address – and that's good, because I don't have an ip6tables configuration.
But I assume, that I could wake up one day, and ifconfig will show me an ipv6 address for the interface – because I have no control over the kernel or its modules – they're under the control of the hosting company. That would leave the server completely vulnerable to attacks from IPv6 addresses.
What would be the best way to disable IPv6 (for the interface or maybe for the entire host)? Usually I would simply disable the kernel module, but that's not possible in this case.
Update
Maybe I should add, that I can use iptables and everything normally (I'm root on the VPS), but I can't make changes to the kernel or load kernel modules because of the way Virtuozzo works (shared kernel).
lsmod always returns nothing.
I can't call ip6tables -L (it says that I need to insmod, or that the kernel would have to be upgraded).
I don't think, that changes to /etc/modprobe.d/aliases would have any effect, or do they?
Networking Config?
I thought, that maybe I can turn IPv6 off from /etc/network/… Is that possible?
Best Answer
I've only tested this on Ubuntu, but you could try the following:
And if this appears to work, you can make it permanent by adding the following to
/etc/sysctl.conf: