Message-Id: <201001182108.o0IL8nBB029112@wind.enjellic.com>
Date:	Mon, 18 Jan 2010 15:08:49 -0600
From:	greg@...ellic.com
To:	Neil Horman <nhorman@...driver.com>, greg@...ellic.com
Cc:	netdev@...r.kernel.org, davem@...emloft.net
Subject: Re: Global IPV6 auto-configuration does not work as expected.

On Jan 18,  3:17pm, Neil Horman wrote:
} Subject: Re: Global IPV6 auto-configuration does not work as expected.

Hi Neil, thanks for the note.

> > The only way we have been able to disable the auto-configuration has
> > been to explicitly disable it at the individual interface level with
> > net.ipv6.conf.ethN.autoconf=0 directives.
> > 
> > We've noted the net.ipv6.conf.default.autoconf and experimented with
> > that a bit as well but haven't been able to accomplish our objective.
> > 
> > Thoughts?
> > 
> > Best wishes for a productive week.
> > 

> First guess would be that you have autoconf configured for you
> interfaces in the config files.  The default sysctl directory just
> controls the state of the device when its first registered, while
> the all sysctl directory provides a 1-shot mechanism to affect the
> state of all devices at once.  Neither prevents autoconfiguration
> from getting set on devices when udev responds to their creation.
> Do the following:
>
> 1) cd /etc/sysconfig/network-scripts
> 2) grep IPV6_AUTOCONF ifcfg*
> 
> If you get any results in step 2 that read like this:
> IPV6_AUTOCONF=yes
> 
> Then your configuration is teling the system to enable autoconf on those
> interfaces.  You can correct that by removing those lines from those config
> file, or changing them to:
> IPV6_AUTOCONF=no

The boxes are not running any of the standard distributions.  They are
running a very minimalistic distribution that I put together in early
1992 and have been maintaining ever since.... :-) So the network
configuration script isn't playing a role in this.

The 'sysctl -p' command is issued by the rc.sysinit script very early
in the boot process.  Long before the interfaces are actually
'upped'.  I'm assuming from your description that the:

net.ipv6.conf.default.autoconf 

If set to 0 before the network interfaces are configured should
prevent auto-configuration from occuring.  I will re-test but I don't
think that is happening.

Also from your description I'm assuming the following:

net.ipv6.conf.all.autoconf=0

If set should globally turn off auto-configuration.

I just tested that again.  After setting the 'all' directive to zero I
removed the IPv6 addresses and after a short time the were
auto-configured again.

For good measure I also set net.ipv6.conf.default.autoconf=0 and
removed the IPv6 addresses.  With both directives set to 0 the IPv6
autoconf address returned.

I'm certainly not discounting user error but according to your
description the net.ipv6.conf.all.autoconf=0 should globally disable
auto-configuration on the interfaces, yet it doesn't seem to.  Unless
the interfaces need to be 'downed' and 'upped' after the sysctl value
is set but that seems counter-intuitive.

> Best
> Neil

Greg

}-- End of excerpt from Neil Horman

As always,
Dr. G.W. Wettstein, Ph.D.   Enjellic Systems Development, LLC.
4206 N. 19th Ave.           Specializing in information infra-structure
Fargo, ND  58102            development.
PH: 701-281-1686
FAX: 701-281-3949           EMAIL: greg@...ellic.com
------------------------------------------------------------------------------
"Programming without software engineering is like sculpting with a
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                                -- Bill Davidsen
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