Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 24 Aug 2006 21:29:43 -0400
From:      Pat Lashley <patl+freebsd@volant.org>
To:        Chuck Swiger <cswiger@mac.com>
Cc:        freebsd-net@freebsd.org
Subject:   Re: Zeroconfig and Multicast DNS
Message-ID:  <961EF4A5A611779A598DE704@garrett.local>
In-Reply-To: <22D92E8D-DE18-4883-8E77-5567AF63DFE0@mac.com>
References:  <20060823221835.GA28978@lor.one-eyed-alien.net> <23D2619F6BACE4E728178EE5@garrett.local> <44ED3BD1.3030206@shapeshifter.se> <AC5769F16F9730CABCCC4E61@garrett.local> <44EDA9A5.2050108@shapeshifter.se> <BE1059C6974AD43BC382E107@garrett.local> <44EDBDD0.4050000@shapeshifter.se> <7CC9AC69410B69EBD31122E4@garrett.local> <44EDDB8C.9090504@shapeshifter.se> <0EC404BA0CA363942D250766@garrett.local> <20060824182640.GA37561@lor.one-eyed-alien.net> <B69C016E0D5F0C26B40BE4C0@garrett.local> <22D92E8D-DE18-4883-8E77-5567AF63DFE0@mac.com>

next in thread | previous in thread | raw e-mail | index | archive | help
> > I think this all means that for a multi-homed host, we should not
> > automatically add a route for the 169.254/16 network.  Instead, we
> > should just add specific /32s as discovered; and use ARP when we
> > need to find a new 169.254.x.y -> MAC translation.
>
> MacOS X has the notion of interface priorities; from RFC-3927:
>
>     Mac OS X ensures that the connected interface with the highest
>     priority is associated with the Link-Local subnet.  Packets  addressed
>     to a Link-Local address are never sent to the default gateway, if  one
>     is present.  Link-local addresses are always resolved on the local
>     segment.
>
>     Mac OS X implements media sense where the hardware and driver  support
>     it.  When the network media indicates that it has been connected,  the
>     autoconfiguration process begins again, and attempts to re-use the
>     previously assigned Link-Local address.  When the network media
>     indicates that it has been disconnected, the system waits four
>     seconds before de-configuring the Link-Local address and subnet.  If
>     the connection is restored before that time, the autoconfiguration
>     process begins again.  If the connection is not restored before that
>     time, the system chooses another interface to autoconfigure.

But OS X also only supports Zeroconf on one interface at a time. We Can Do 
Better.

> > There still remains the possibility of multiple distinct hosts
> > having the same LLA IP address on separate local links; each
> > attached to a separate interface. In practice that situation should
> > be sufficiently rare that we can afford to ignore it until someone
> > comes up with some clever way to handle it. (Or we all move to IPv6
> > and it becomes moot.)
>
> See section 4 of RFC-3927.

No, that covers merging two previously disjoint networks; I don't think that it 
is intended to handle the case of a multi-homed host that is connected to both 
of them while keeping them separate.



-Pat 



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?961EF4A5A611779A598DE704>