Re: Disabling ip4 and IPV6 on F20RC1

[Bjørn Mork <bjorn mork no>]

Pavel Simerda <psimerda redhat com> writes:

> > > there isn't any possibility to disable IPv6 link-local addresses. In
> > > fact it's not properly supported even in the kernel.
> >
> > echo 1 > /proc/sys/net/ipv6/conf/$DEVICE/disable_ipv6 works for me?
>
> 1) First of all it doesn't *specifically* disable kenrel link-local
> addresses allocation but performs some magic to disable a couple of
> IPv6 features at once. This wouldn't be a problem in the original
> poster's case as he wants to disable IPv6 anyway.

That's sort of implied, isn't it?  You cannot remove all IPv6 LL
addresses from an interface without disabling IPv6. This is a protocol
requirement.  Ref e.g. RFC 4291:

   2.8.  A Node's Required Addresses

   A host is required to recognize the following addresses as
   identifying itself:

      o Its required Link-Local address for each interface..
[etc]


> 2) But setting disable_ipv6 doesn't really work as expected. See [1]
> and especially the note about disable_ipv6 below the table.

I read that note, but couldn't figure out what expectations that would
be. FWIW, disable_ipv6 works for me as well. That is:  The behaviour
matches my expectations.  Which are

  /proc/sys/net/ipv6/conf/$DEVICE/disable_ipv6 = 1
     => no IPv6 LL address on $DEVICE

  /proc/sys/net/ipv6/conf/$DEVICE/disable_ipv6 = 0
     => IPv6 supported, including an EUI-64 based LL address

  changing IFF_UP does not affect the above in any way

Are you sure this wasn't one of the bugs fixed by commit 73a8bd74e261
("ipv6: Revert 'administrative down' address handling changes.")?  It's
difficult to tell from the link you gave, because it just refers to an
unspecified "kernel".  Which could be a FreeBSD kernel for all I know
:-)


Bjørn