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[Bug 96578] Re: The sysctl net.ipv6.conf.all.autoconf does not apply to "all"


The answer for IPv4 was figured out here:

The behaviour is non-obvious. For some settings the interface and 'all'
settings are ANDed together; for others they are OR'd, for others the
MAX is taken.

send_redirects is an OR, which means you can enable sending of redirects
on all interfaces (conf.all.send_redirects=1) but you cannot disable
sending them on all interfaces. In that case you have to set
conf.all.send_redirects=0 *and* set each individual interface.

So in /etc/sysctl.conf you have to list all the interfaces which the
host has (or may have) at startup time, if you want to disable sending
of redirects on those interfaces. A tri-state setting for conf.all would
be much more useful, but that's not what we have.

Now back to the original report, which was about
net.ipv6.conf.all.autoconf=0. What is the intended behaviour from the
kernel authors?

include/linux/inetdevice.h appears to have IPv4 settings only. For IPv6:

grep -R devconf_all net/ipv6

Unfortunately it's not obvious to me how "all" + interface-specific
parameters  interact for IPv6. There are some places where the two are
explicitly combined: e.g.

                     (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&

I don't see anything similar for autoconf. However there is:

MODULE_PARM_DESC(autoconf, "Enable IPv6 address autoconfiguration on all interfaces");

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  The sysctl net.ipv6.conf.all.autoconf does not apply to "all"

Status in “linux” package in Ubuntu:
Status in “linux-source-2.6.20” package in Ubuntu:

Bug description:
  Binary package hint: linux-source-2.6.20

  Just specifying:


  in sysctl.conf does not actually disable autoconf.

  Explicitly setting


  on the other hand does work (if I've added "ipv6" to /etc/modules, but
  that's another issue).

  Our workaround for this is to list enough ethN to cover "all likely" network interfaces, but that's not exactly a neat solution.
  AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
  Architecture: amd64
   **** List of CAPTURE Hardware Devices ****
   card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
     Subdevices: 2/2
     Subdevice #0: subdevice #0
     Subdevice #1: subdevice #1
   Cannot stat file /proc/4797/fd/11: No such file or directory
                        USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  maswan     2400 F.... pulseaudio
   /dev/snd/pcmC0D0p:   maswan     2400 F...m pulseaudio
  CRDA: Error: [Errno 2] No such file or directory
   Card hw:0 'Intel'/'HDA Intel at 0xf3020000 irq 21'
     Mixer name	: 'Analog Devices AD1884'
     Components	: 'HDA:11d41884,103c2819,00100100'
     Controls      : 30
     Simple ctrls  : 18
  DistroRelease: Ubuntu 10.04
   lo        no wireless extensions.
   eth0      no wireless extensions.
   ppp0      no wireless extensions.
  MachineType: Hewlett-Packard HP Compaq dc7800 Convertible Minitower
  NonfreeKernelModules: openafs
  Package: linux (not installed)
  ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-33-generic root=/dev/mapper/rootvg-rootlv ro quiet splash
   PATH=(custom, user)
  ProcVersionSignature: Ubuntu 2.6.32-33.71-generic
  Regression: No
  RelatedPackageVersions: linux-firmware 1.34.7
  Reproducible: Yes
  Tags: lucid kconfig needs-upstream-testing
  Uname: Linux 2.6.32-33-generic x86_64
  UserGroups: adm admin audio cdrom dialout dip floppy fuse lpadmin plugdev video voice
  dmi.bios.date: 02/26/2009
  dmi.bios.vendor: Hewlett-Packard
  dmi.bios.version: 786F1 v01.28
  dmi.board.asset.tag: CZC84703HB
  dmi.board.name: 0AACh
  dmi.board.vendor: Hewlett-Packard
  dmi.chassis.asset.tag: CZC84703HB
  dmi.chassis.type: 6
  dmi.chassis.vendor: Hewlett-Packard
  dmi.modalias: dmi:bvnHewlett-Packard:bvr786F1v01.28:bd02/26/2009:svnHewlett-Packard:pnHPCompaqdc7800ConvertibleMinitower:pvr:rvnHewlett-Packard:rn0AACh:rvr:cvnHewlett-Packard:ct6:cvr:
  dmi.product.name: HP Compaq dc7800 Convertible Minitower
  dmi.sys.vendor: Hewlett-Packard

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