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Re: RFC 2553 bind semantics harms the way to AF independence

In seems to me that all this discussion about what the default
behavior should be when binding to a wildcarded AF_INET6 socket
doesn't address the issue: deterministic behavior for portable
application across multiple operating systems.

And just to lay my cards on the table, I support the current
default behavior of having AF_INET6 sockets receive both IPv4 and
IPv6 packets.

Isn't the real problem that we have added an IPV6_V6ONLY option,
but not an IPV6_V4ANDV6 option?.  If we add that, then portable
applications can explictly state what actions they want, and they
don't have to worry about OS defaults.  The success and failure
cases are then obvious and well defined:

	bind#1	AF_INET6 w/IPV6_ONLY
	 bind#2	AF_INET6 - fail
	 bind#2	AF_INET4 - succeed

	bind#1 	AF_INET6 w/IPV6_V4ANDV6
	 bind#2	AF_INET6 - fail
	 bind#2	AF_INET4 - fail

	bind#1	AF_INET4
	 bind#2	AF_INET6 w/IPV6_ONLY - succeed
	 bind#2	AF_INET6 w/IPV6_V4ANDV6 - fail

Thus, you have deterministic behavior.  And that's the end goal
for portable applications, isn't it?

			-David Borman, dab@bsdi.com
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