Subject: Re: Application software needs to be "zeroconf-aware"?

From: Stuart Cheshire <[email-masked]>
Date: Fri, 27 Dec 2002 18:21:44 -0800

>> The point of 
>> Zeroconf is not that we don't need a worldwide Internet. The point of 
>> Zeroconf is that it would be useful to be able to use that same IP 
>> software when you're not connected to the Internet. 
>
>then please fix v4LL so that it's disabled whenever you are connected to
>a larger network.  that way it won't break anything that already works.

The problem is how a device with no screen and no keyboard can detect 
with absolute certainty that it is "connected to a larger network" AND 
that it is correctly configured for that network.

If the device is ever wrong, then you get into the situation where it 
can't communicate because it is configured wrong, and it thinks it's 
configured right so it's disabled v4LL, so now you can't communicate with 
it to fix the incorrect configuration.

Stuart Cheshire <[email-masked]>
 * Wizard Without Portfolio, Apple Computer, Inc.
 * Chairman, IETF Zeroconf
 * www.stuartcheshire.org

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From: Keith Moore <[email-masked]>
Date: Fri, 27 Dec 2002 21:29:54 -0500

> that it is correctly configured for that network.

if a host is explicitly configured to have any external routes, OR
any routes to other prefixes are discovered by the host through DHCP, RIP, 
or any other mechanism supported by the host and enabled on that host, it's 
connected to a larger network.

yes there can be rogue DHCP servers or RIP advertisements, but trying to 
detect errors in the configuration of managed networks should not be in 
scope for zeroconf.  

Keith

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From: "John C. Welch" <[email-masked]>
Date: Fri, 27 Dec 2002 23:39:57 -0500

> connected to a larger network.

No, you assume it is. Why is this assumption *okay* with DHCP, or any other
current configuration mechanism for you, yet the same level of assumption
for LL is somehow evil?

> detect errors in the configuration of managed networks should not be in

No, but then, zeroconf won't interfere with these unless your OS is
incapable of handling more than one address per interface, but then I'd
wonder how you are running Zeroconf on a System 6 Mac, or a DOS 5.0 PC, and
more importantly , *why*?

 john

-- 
John C. Welch
Consultant III
Administrative Computing
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