Maintained by: NLnet Labs

unbound-anchor ignores net.ipv6.conf.all.disable_ipv6=1 in /etc/sysctl.conf

Robert Edmonds
Wed Nov 4 01:32:58 CET 2015

Paul Wouters via Unbound-users wrote:
> FYI:
> rhbz#1231946 - unbound-anchor ignores net.ipv6.conf.all.disable_ipv6=1 in /etc/sysctl.conf
> Paul

Hi, Paul:

I'm a bit confused.  unbound-anchor is an ordinary program that uses the
sockets API, so it should have no reason to read Linux kernel specific
sysctl's or change behavior based on their values, since sysctl's are
parameters for the kernel.

kmod="net-pf-10" is the IPv6 protocol family, and Red Hat kernels have
CONFIG_IPV6=y these days, so it could not autoload the module anyway.
Maybe IPv6 is not really fully disabled, and unbound-anchor attempting
to open an AF_INET6 socket triggers this message?

I came across this page (
which seems to match the problem description, but the solution is
paywalled, perhaps you have better access :-)

Robert Edmonds
edmonds at