Eliminating IPv6 (?)

Marek Zarychta zarychtam at plan-b.pwste.edu.pl
Tue Jun 18 08:33:45 UTC 2019

W dniu 18.06.2019 o 10:09, christian russell pisze:
> My opinion is that being able to practically ignore IPv6, without operational detraction, is a reasonable degree of freedom.  FreeBSD isn’t pushing IPv6 any more or less than any other mainstream OSes.
> Given a set number of developer hours I would prefer that IPv6 be fully implemented and functionally "ignorable" as opposed to dev time being spent allowing an essentially cosmetic opting out of IPv6 functionality.  Even more generally I would prefer any dev time time be spent on active issues and new features.
>> I ask again, is this really such an unreasonable thing to hope for?
> If I were allocating work-hours on FreeBSD development my answer would be:  “yup"  ¯\_(ツ)_/¯
> Christian

Dual stack support looks like a reasonable solution these days and works
fine in 99% of network scenarios. From the other hand the ability to
completely disable legacy IP should be considered as well. Some people
consider IPv6 only network to be providing a sufficient degree of
freedom but in 2019 we still lack DHCPv6 client in base.

Marek Zarychta

>> On Jun 18, 2019, at 12:44 AM, Ronald F. Guilmette <rfg at tristatelogic.com> wrote:
>> 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
>>> /etc/src.conf
>>> 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.
>> Regards,
>> rfg
>> 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:
>>    ipv6="NO"
>> That in turn should be checked -and- respected by all relevant /etc/rc,d/
>> scripts.
>> I ask again, is this really such an unreasonable thing to hope for?
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