Thanks Alexey

Brian, I would presume that the IESG will be looking for an update responsive 
to these comments.

On Jun 6, 2011, at 4:17 AM, Alexey Melnikov wrote:

> I am the assigned Gen-ART reviewer for this draft. For background on
> Gen-ART, please see the FAQ at
> <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. Please
> resolve these comments along with any other Last Call comments you may
> receive.
> 
> 
> Document: draft-ietf-v6ops-6to4-advisory-01.txt
> Reviewer: Alexey Melnikov
> Review Date: 2011-06-06
> IETF LC End Date: 2011-06-16
> IESG Telechat date:
> 
> 
> 
> Summary: ready (with nits) for publication as an Informational RFC.
> 
> Major issues: none
> 
> Minor issues: none
> 
> Nits:
> 
> 2.1.  Router 6to4
> 
>   Some 6to4 routers are also configured as "Relay routers."  They
>   behave as just described, but in addition they obtain native IPv6
>   connectivity with a normal IPv6 prefix.  They announce an IPv6 route
>   to 2002::/16.  For example, assume that the 6to4 router at
>   190.0.2.187 is a relay router, whose address on the 6to4 side is
>   2002:c000:2bb::1.  Suppose that a host with the 6to4 address 2002:
>   c000:2aa::123 sends an IPv6 packet to a native IPv6 destination such
>   as 2001:db8:123:456::321.  Assume that the 6to4 router at 192.0.2.170
>   has its IPv6 default route set to 2002:c000:2bb::1, i.e. the relay.
>   The packet will be delivered to the relay, encapsulated in IPv4.
>   After decapsulation, the relay will forward the packet into native
>   IPv6 for delivery.
> 
> I might be getting confused, but is "the relay" in the last 2 quoted 
> sentences mean 2 different things?
> 
>   When the remote host replies, the packet (source
>   2001:db8:123:456::321, destination 2002:c000:2aa::123) will find a
>   route to 2002::/16 and hence be delivered to a 6to4 relay.  The
>   process will be reversed and the packet will be encapsulated and
>   forwarded to the 6to4 router at 192.0.2.170 for final delivery.
> 
> 
> 3.  Problems Observed
> 
>   7.  Bogus Address Failure: By design, 6to4 does not work and will not
>       activate itself if the available V4ADDR is a private address
>       [RFC1918].  However it will also not work if the available V4ADDR
>       is a "bogon", i.e. a global address that is being used by the
>       operator as a private address.  A common case of this is a legacy
>       wireless network using 1.1.1.0/24 as if it was a private address.
>       In this case, 6to4 will assume it is connected to the global
>       Internet, but there is certainly no working return path.
> 
>       This failure mode will also occur if an ISP is operating a
>       Carrier Grade NAT between its customers and the Internet, and is
> 
> I think adding a reference to an RFC that defines the term would be useful 
> here. (I've seen the term with a proper reference recently, but I don't 
> remember the name of the document.)
> 
>       using global public address space as if it were private space to
>       do so.
> 
> 4.5.  Content providers and their ISPs
> 
>   Content providers who do embed the relay function in this way could,
>   in theory, accept inbound 6to4 traffic as well.  This is highly
>   unadvisable since, according the the rules of 6to4, they would then
>   have to relay traffic for other IPv6 destinations too.  So they
>   should not be reachable via 192.88.99.1.  Also, they should certainly
>   not create an AAAA record for their 6to4 address - their inbound IPv6
>   access should be native, and advertising a 6to4 address might well
>   lead to uRPF ingress filtering problems.
> 
> What is uRPF?
> 
> 
>   [RFC3056]  Carpenter, B. and K. Moore, "Connection of IPv6 Domains
>              via IPv4 Clouds", RFC 3056, February 2001.
> 
>   [RFC3068]  Huitema, C., "An Anycast Prefix for 6to4 Relay Routers",
>              RFC 3068, June 2001.
> 
> I believe these 2 references need to be Normative, as they are required to 
> understand this document.
> 

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