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Date:      Wed, 27 Aug 2014 11:59:25 +0000
From:      "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>
To:        Jonathan Price <freebsd@jonathanprice.org>
Cc:        FreeBSD Net <freebsd-net@freebsd.org>, Hiroki Sato <hrs@FreeBSD.org>
Subject:   Re: Should I be using ipv6_activate_all_interfaces or ip6addrctl_policy="ipv6_prefer"
Message-ID:  <2D16BCE4-5E5A-4C06-8927-76953DDEC348@lists.zabbadoz.net>
In-Reply-To: <53FD7B34.1050408@jonathanprice.org>
References:  <88a42e1006e3fac7508a9419e342f1b2@mail.jonathanprice.org> <2173103.SJdXL7NPLT@overcee.wemm.org> <53FD7B34.1050408@jonathanprice.org>

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On 27 Aug 2014, at 06:31 , Jonathan Price <freebsd@jonathanprice.org> =
wrote:

> On 2014-08-27 01:40, Peter Wemm wrote:
>> On Tuesday 26 August 2014 10:40:27 freebsd@jonathanprice.org wrote:
>>> Hello,
>>>=20
>>> I am configuring a server with IPv4 and IPv6 addresses and have =
noticed that
>>> FreeBSD seems to be preferring IPv4, such as when establishing SSH
>>> connections.
>>>=20
>>> After reading through /etc/defaults/rc.conf, and later =
/etc/rc.d/ip6addrctl
>>> I have come to the conclusion that I have two ways to tell FreeBSD =
to
>>> prefer IPv6:
>>>=20
>>> 1) Add ipv6_activate_all_interfaces to /etc/rc.conf
>>> 2) Add ip6addrctl_policy=3D"ipv6_prefer" to /etc/rc.conf
>>>=20
>>> Could anybody with a little more knowledge on the matter explain to =
me which
>>> of the two options is more preferential?
>>=20
>> They both do different things.
>>=20
>> The activate knob is to enable ipv6 on an interface.  To oversimplify =
it, if
>> you configure an address on an interface, it is "enabled".  However, =
this
>> switch enables this on all the rest of the interfaces, even the ones =
you
>> didn't configure.
>>=20
>> ip6addrctl* affects things like hostname lookups to sort the =
addresses returned
>> to the caller.
>>=20
>> They are different things entirely.  I think you are expecting the =
behavior
>> that ip6_prefer policy gives you.  That's what we use in the =
freebsd.org
>> cluster to have it use ipv6 where possible.
>>=20
>=20
> Hi, and thanks for the response.
>=20
> Would it be possible to go into a little detail as to what =
ipv6_activate_all_interfaces=3D"YES" does to interfaces which don't =
explicitly have an address configured? I can=92t appear to find much =
information on this option.

man rc.conf

has a description (which I should probably read myself;-) in case that =
gets you a bit further.   I think it=92s a =93backward compat helper=94 =
to the old ipv6_enable=3D=93YES=94 switch which existed before we could =
enable IPv6 on a per-interface base.


> However, it does sound like for my purposes it would make more sense =
to use ip6addrctl_policy=3D=93ipv6_prefer" as that is more explicitly =
the feature I want, rather than getting it inadvertently through the =
other knob.

Yes. Definitively.  I am not sure if it has happened but if IPv6 config =
is configured through rc.conf that setting should be(come) default.


Bjoern

=97=20
Bjoern A. Zeeb             "Come on. Learn, goddamn it.", WarGames, 1983




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