Currently, in IPv6 environments, there is a known issue where the IPv6 key-value pair, `IPV6_AUTOCONF=no`, in `ifcfg-*` files generated by `os-net-config` does not prevent the system from configuring the default route in response to router advertisements. + *Workaround:* perform the following steps to correct this issue: + . Set `net.ipv6.conf.<interface>.accept_ra_defrtr=0` to prevent learning the default route from router advertisements and `net.ipv6.conf.<interface>.accept_ra=0` to prevent the system from accepting router advertisements for any routes. Set both of these variables in `/etc/sysctl.conf` or `/etc/sysctl.d/99-sysctl.conf` (or another file in that subdirectory): + * For each specific interface: + ---- net.ipv6.conf.<interface>.accept_ra_defrtr=0 net.ipv6.conf.<interface>.accept_ra=0 ---- + [NOTE] Setting each specific interface can help to ensure that the settings are not overridden. * For newly created interfaces: + ---- net.ipv6.conf.default.accept_ra_defrtr=0 net.ipv6.conf.default.accept_ra=0 ---- * For all interfaces present at boot time: + ---- net.ipv6.conf.all.accept_ra_defrtr=0 net.ipv6.conf.all.accept_ra=0 ---- . Run the following command: + ---- $ sudo sysctl -p ---- . Alternatively, you can run the `sysctl` command to activate and write these values to the `sysctl.conf` file: + * For each specific interface: + ---- $ sudo sysctl -w net.ipv6.conf.<interface>.accept_ra_defrtr=0 $ sudo sysctl -w net.ipv6.conf.<interface>.accept_ra=0 ---- + [NOTE] Setting each specific interface can help to ensure that the settings are not overridden. * For newly created interfaces: + ---- $ sudo sysctl -w net.ipv6.conf.default.accept_ra_defrtr=0 $ sudo sysctl -w net.ipv6.conf.default.accept_ra=0 ---- * For all interfaces present at boot time: + ---- $ sudo sysctl -w net.ipv6.conf.all.accept_ra_defrtr=0 $ sudo sysctl -w net.ipv6.conf.all.accept_ra=0 ----