Subject: Catalog of IPv4 literals

From: Cameron Byrne <[email-masked]>
Date: Sun, 25 Jul 2010 09:01:12 -0700

Folks,

It has been suggest several times to me that IPv4 literals be
cataloged in a central location so that those working to develop
IPv6-only networks and services can know the impact of IPv4 addresses
that are hard-coded into content and protocols.  So, i created this
Google Groups http://groups.google.com/group/ipv4literals and provided
an example template for reporting found IPv4 literals.  Right now, the
threat of IPv4 literals on IPv6-only networks is small from the
network operator perspective, it is not a blocking issue.  But, for
the content owners who knowingly or unknowingly have IPv4 literals as
part of their service, this is major breakage.  That said, they have a
right to know how their service will break so that they can accept the
risk of having their content unavailable on major networks or work to
use DNS names that will function correctly.  Extra bonus points if
they resolve this issue of inter-operating with IPv6-only networks by
producing native IPv6 content!

In my own efforts, i have found content owners very happy to receive
this proactive notification.  Explicitly, myspace and Yahoo! have been
very good partners in finding and resolving issues of this nature and
removing IPv4 literals from their production services.  Also, over the
course of my work I have seen Hulu.com independently move to using DNS
names.  The issue is most commonly found with streaming services on
the Internet, especially ones involving CDNs.

Best regards,

Cameron

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From: [email-masked]
Date: Sun, 25 Jul 2010 20:08:45 +0000

if an application "breaks" becuase someone uses an address literal instead
of a domain name, then that application is itself broken.  the DNS translates
the name into an address and the address is used...  so whether a name or
a literal is handed to the app should be immaterial.  

so your "catalog" of address literals is really the full set of all IP addresses.

--bill

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From: Cameron Byrne <[email-masked]>
Date: Sun, 25 Jul 2010 14:02:59 -0700

> a literal is handed to the app should be immaterial.

Please think of the scope as limited to
draft-ietf-behave-v6v4-framework scenario #1, IPv6 network to an IPv4
internet.  If an IPv4 literal is passed at the application layer
(HTML, XML, ...) to a host with only IPv6 connectivity, the service is
broken to an IPv6-only user as where it works for an IPv4-only user.
Pedantry aside, this is the customer experience for some common
internet services.  DNS names solve this problem since they allow
DNS64 to function.

This  draft draft-wing-behave-http-ip-address-literals attempts to
work around the problem of IPv4 literals passed to hosts in IPv6-only
networks, but the work around is only relevant for HTTP and will not
work for smartphones or dumbphones that don't have this proxy logic.

> so your "catalog" of address literals is really the full set of all IP addresses.

No.

Cameron

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From: [email-masked]
Date: Sun, 25 Jul 2010 21:10:08 +0000

> internet services.  DNS names solve this problem since they allow

	ok... then its a self-inflicted wound. IPv6 mapped addresses
	worked just fine until this wg depricated them.
	wrt DNS64,  the translate functions I've been using for several
	years now doesn't require such hacks. 

> work for smartphones or dumbphones that don't have this proxy logic.

	yes, this turns out to be (as previously noted) an APPLICATION
	level problem.  and i really question the wisdom of spending too 
	much time on this corner/transition case.

> > so your "catalog" of address literals is really the full set of all IP addresses.

	if you place all of the above restrictions on your premise, then I
	agree with you.

--bill