[ale] ifup problems, possible IPv6

[Michael H. Warfield]

On Thu, 2005-02-03 at 10:07 +0000, Tony Carter wrote:
> On Wednesday 02 February 2005 23:07, Michael H. Warfield wrote:
> snip..
> >You also have
> > to reboot the system in order to remove IPv6 from the running kernel.
> > You can not simply rmmod it.  No workie...
> >
> > > -Jay
> Actually to stop the module from loading, you have to recompile the kernel 
> without ipv6 support.

	No, you don't.  AFAIK, no distro is shipping the kernel with IPv6
compiled into the kernel.  It's being delivered as a module.  The
earlier comment about setting alias net_pf_10 to off in modules.conf is
absolutely correct, to prevent it from being modloaded upon reference.
But you also have to reboot to unload it.  To prevent it from even being
loaded manually, you have to remove the ipv6.ko file from the modules
directory and (optionally) rerun depmod -a.  You do NOT have to
recompile the kernel under these cases.  The ONLY case where you would
have to recompile the kernel is when IPv6 has been compiled "y" (hard
link) into the kernel, but then it would have to be a custom kernel and,
thus, a self inflicted injury.  Presumably, having done that to
yourself, you would have enough sense to know how to undo it.  Building
a custom kernel on Fedora Core 3 is a royal pain in the fanny, since it
no longer has a "sourcecode" rpm and the SRPM has to be used and that
can't be installed or updated by yum.  Building a vanilla kernel from a
primary kernel.org tarball is even further out there.  If you are that
deep into building a custom kernel, you probably don't need ANY of the
advise in this thread.

> and another way to disable ipv6:
>  echo "NETWORKING_IPV6=no" >> /etc/sysconfig/network

	Bzzzttt...  Wrong answer.  That's the default anyways.  Try it.  It
won't make one lick of different on FedoraCore 2 or 3, because it's
already "no".  All that does is prevent IPv6 from being configured.  It
doesn't prohibit it from being loaded.  It's being loaded because one of
the networking utilities made reference to  "PF_INET6" in a socket call
and the kernel automagically loaded the net_pf_10 module to oblige the
request.  Only problem is, none of the IPv6 routes and defaults are
configured, so it's simply coming up in its default state and adding
link-local addresses to all the interfaces and enabling
autoconfiguration (in case you've got a router out there advertising
IPv6 routes and prefixed to autoconfig global addresses) and sending
router solicitation messages.

	Basically, neither of your recommendations will have any impact, what
so ever, on most RedHat / RPM based distros.

	Check it out.  Try it for yourself.  I have.

> -Tony

	Mike
-- 
 Michael H. Warfield    |  (770) 985-6132   |  mhw at WittsEnd.com  
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