Eliminating IPv6 (?)

Ronald F. Guilmette rfg at tristatelogic.com
Tue Jun 18 07:44:37 UTC 2019

In message <d6a5d6b8-1630-3095-dd0b-22b49213176e at grosbein.net>, 
Eugene Grosbein <eugen at grosbein.net> wrote:

>18.06.2019 10:10, Ronald F. Guilmette wrote:
>> How can I turn off IPv6 entirely without rebuilding the kernel?
>You cannot. GENERIC kernel specifically enables IPv6 support and you need to
>disable it at compile time.
>And if you do, you better rebuild the world too using WITHOUT_INET6=yes in the
>or else some utilities compiled with INET6 by default will query kernel
>for IPv6-specific data (like routing entries) and complain that your kernel does 
>not know about it.
>World built WITHOUT_INET6 has no such rough edges.

OK, so I obviously expressed myself badly.  Let me try again.

IPv6 support is enabled in a the stock kernel.  OK.  Fine.  But just because
that feature is present in the kernel, that does not imply that anything in
userland -has- to actually make any use of it at all.

*Something* is doing ifconfig on my loopback (lo0) interface.  What is that
thing and how can I get it to stop doing that?

As I have already learned, the /etc/rc.firewall script also assumes both the
presence of, and the desirability of IPv6 support.  And unless one edits that
file manually... which I have been effectively forced to do... there is no way
to get it to simply NOT create and install multiple IPv6-related ipfw rules,
EVEN THOUGH in my particular situation... which is still the most common case...
those extra and entirely superfluous IPv6 ipfw filtering rules are serving
no earthly purpose whatsoever and are only cluttering up my ipfw rule set,
thus pointlessly making it harder for me to grok and maintain them all.

Clearly, if doesn't have to be this way.  Some maintainers just decided that
I and all other IPv4-only users should get stuck dealing with a lot of useless,
unnecessary and distracting IPv6 stuff, whether I like it or not, and presumably
for our own good.

I really wish that maintainers would allow me a bit more freedom, and show
me the courtesy and respect to allow me to decide for myself what is and what
isn't "for my own good".

I can and will most certainly get down and grovel around in the various
/etc/rc.d/ scripts and will comment out those parts that do things like
ifconfig'ing my loopback interface for IPv6, whether I like it or not.
But there ought to be some single /etc/rc.conf variable via which one could
simply select the "No, I don't want to have to deal with IPv6 at all right
now" option.

Is that really an unreasonable hope, expectation, and request?

I understand that the kernel will still -offer- the IPv6 support. But if no
-other- software on my system actually takes the kernel up on that offer,
then the kernel's IPv6 support becomes like the tree that falls in the
forrest when there is nobody around to hear it.  It might as well be said
that it makes no sound, and no difference to anything at all.

It is clearly not necessary for me or anyone else to have to rebuild the
kernel... *and* world... just in order to get rid of what are, for the
majority of users here in 2019, still a bunch of utterly superfluous IPv6
"features" that (a) do not help us one iota and that (b) are all just a
big and pointless distraction that muddles everything and unnecessarily
complicates and complexifies ordinary system maintenance tasks.

IPv6 is great and I'm sure I'll be using it someday.  But today is not that
day... not for me, and also not for one hell of a lot of other users.  The
fact that I and others are effectively being forced to even think about it,
due to an absence of reasonable and easily accessible userland options, is
actually a big turn-off, and leaves a bad taste in the mouth which will
be remembered, in future, at every mention of IPv6.  I hope that all of the
IPv6 evanglists will take a moment to stop and think about that, and that
they'll stop effectively forcing those of us who don't need it to both use
IPv6 and to think about it, whether we like it or not, and before we are ready,
willing, and able to do so.


P.S.  In case I have again failed to be clear, I am proposing a new /etc/rc.conf
option.  Something simple and intutive like:


That in turn should be checked -and- respected by all relevant /etc/rc,d/

I ask again, is this really such an unreasonable thing to hope for?

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