Date: Thu, 23 Oct 2003 11:45:04 -0700 From: Wes Peters <wes@softweyr.com> To: Charles Swiger <cswiger@mac.com>, net@freebsd.org Subject: Re: Help Broadcasting a UDP packet on the LAN:URGENT Message-ID: <200310231145.04241.wes@softweyr.com> In-Reply-To: <109F1559-0586-11D8-92E1-003065ABFD92@mac.com> References: <109F1559-0586-11D8-92E1-003065ABFD92@mac.com>
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On Thursday 23 October 2003 11:23 am, Charles Swiger wrote:
> On Thursday, October 23, 2003, at 11:52 AM, Barney Wolff wrote:
> > On Thu, Oct 23, 2003 at 01:55:55AM -0700, Wes Peters wrote:
>
> [ ... ]
>
> > What are you going to do when IPv6 comes into more general use, since
> > it has no broadcast address?
>
> Are you asking what a IPv4-to-IPv6 translator (like gif?) should do, or
> are you worried about the case of a machine configured for IPv6 only
> and not for IPv4? I expect that most people will be using IPv4 for
> quite some time; we don't have to do something for the IPv6-only case
> to still have this be useful.
Porting broadcast applications to IPv6 requires re-thinking the problem,
because IPv6 sheds some of the problems of IPv4 and introduces a few of
it's own. Address assignment, for instance, is much less a problem in
IPv6, but not having the addresses centrally managed (by either a program
or a human) introduces it's own difficulties.
> > The whole VLAN thing is nasty, but I'd say that the general issue is
> > does the box itself have a virtual interface on the VLAN, or is it
> > merely switching on it. If the former, you send packets and process
> > received packets up the stack. If the latter, you just do what any
> > switch/bridge would do, because "you" (ie, higher layers) are not
> > really
> > on that layer-3 network.
>
> The all-ones broadcast is supposed to go to all physically connected
> network segments, regardless of whether a particular interface is
> ifconfig'ured with an IP that is part of a particular layer-3 subnet.
> You should be able to send the broadcast packet out from an interface
> which is up but does not have an IPv4 address assigned, right?
So long as it IS configured with the IPv4 protocol, I'd say yes. Ditto
for VLANs.
--
Where am I, and what am I doing in this handbasket?
Wes Peters wes@softweyr.com
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