does not configure ipv6 vlan interfaces due to autoconf sysctl failure

Status changed to 'Confirmed' because the bug affects multiple users.

Workaround: Use "iface vlanXX" syntax:

iface vlan83 inet static
 vlan-raw-device eth0
...

I think this is essentially the same as the RHEL bug https://bugzilla.redhat.com/show_bug.cgi?id=665601 that was fixed earlier this year.

This bug was fixed in the package ifupdown - 0.7~beta2ubuntu1

---------------
ifupdown (0.7~beta2ubuntu1) precise; urgency=low

  * Resynchronise with Debian experimental. Remaining changes
    (LP: #905660, LP: #850566, LP: #611877, LP: #678425):
    - ifupdown.nw: Use 100 as default route metric unless an explicit metric
      parameter is set in /etc/network/interface.
    - Add iniparser3.0b sources (dictionary.c, dictionary.h, iniparser.c,
      iniparser.h), to let ifupdown avoid auto-up/down of interfaces if
      network-manager's ifupdown plugin is in managed=true mode.
    - Add a new query interface, 'ifquery', that can be used by upstart
      hooks to ask for the list of possible interfaces that they might need
      to bring up.
    - debian/ifupdown.network-interface.upstart: Replace the init scripts
      with a per-interface Upstart job.
    - debian/ifupdown.networking.upstart: Add a "networking" job that
      partially replaces the networking init script from netbase.
    - debian/control: Bump build-dependency on debhelper for Upstart-aware
      dh_installinit.
    - debian/rules: Due to debhelper always adding /etc/init.d symlinks, we
      must manually remove /etc/init.d/networking for as long as netbase
      still provides it.
    - Add if-up and if-down scripts to emit Upstart events when interfaces
      come up and go down.
    - debian/ifupdown.network-interface-security.upstart: Ensure apport is
      started before interfaces are brought up by either ifupdown or
      network-manager.
    - debian/postinst: If the loopback interface is missing from the config
      in /etc/network/interfaces, add it on upgrade.
    - debian/ifupdown.preinst: Since files in /etc were not conffiles in
      lucid, and /etc/network/if-up.d/upstart and
      /etc/init/network-interface.conf changed between lucid final and
      maverick, add extra handling to avoid spurious conffile prompts.
    - invoke dhclient3 with '-1', meaning it should exit failure if it does
      not receive a response in 60 seconds. (LP: #838968)
    - contrib/ifstate-check: Use /run/ntework/ifstate instead of
      /etc/network/run/ifstate
    - ifup.8: Update man page to indicate that Ubuntu uses /run
      and that it's always writable as it's a temporary filesystem
  * ifupdown.nw: When calling dhclient3, also use /var/lib/dhcp as
    dhclient3 is now a symlink to dhclient and /var/lib/dhcp3 no longer
    exists. (LP: #900234)
  * Mark ifupdown as Multi-Arch foreign
  * Replace remaining references to /var/run/network by /run/network
    (LP: #885506)

ifupdown (0.7~beta2) experimental; urgency=low

  * Put interfaces down in the reverse order than they were
    brought up (Closes: #477650).
  * Fix postinst issues with loopback interface naming
    (Closes: #572396, #545250).
  * Remove old .dpkg-old symlink (Closes: #639612).
  * Document some details on processing /etc/network/if-*.d directories.
  * Terminate ifup if it's still running when doing ifdown.
  * Finally migrate to /run/network.
  * Use FHS names for wvdial pid files (Closes: #255222).
  * Stop on run-parts failure (Closes: #547587).
  * Execute scripts before interface options on *...

Hello! This problem still exists on Ubuntu 14.04.

It makes impossible to deactivate RA on a VLAN interface.

The command "sysctl -p" doesn't work when a line like this exists:

VLAN20:

"net.ipv6.conf.eth0.20.accept_ra=0"

It doesn't work either...

As a great workaround, I stopped using VLAN interfaces like "eth0.X", and now I'm using it like this "vlanX"... It is working better (still no not free of problems).