RE: I-D Action: draft-ietf-6man-rfc6434-bis-01.txt

Hi Bob,

> -----Original Message-----
> From: Bob Hinden [mailto:bob.hinden@gmail.com]
> Sent: Wednesday, September 20, 2017 10:40 AM
> To: Templin, Fred L <Fred.L.Templin@boeing.com>
> Cc: Bob Hinden <bob.hinden@gmail.com>; Timothy Winters <twinters@iol.unh.edu>; Russ White <russ@riw.us>; IPv6 List
> <ipv6@ietf.org>
> Subject: Re: I-D Action: draft-ietf-6man-rfc6434-bis-01.txt
> 
> Fred,
> 
> > On Sep 20, 2017, at 8:29 AM, Templin, Fred L <Fred.L.Templin@boeing.com> wrote:
> >
> > Hi Tim,
> >
> > The specific case I am considering is documented here:
> >
> > https://datatracker.ietf.org/doc/draft-templin-v6ops-pdhost/
> >
> > But in general the RFC1122 considerations for hosts that act as routers,
> > including what is meant by “weak end system” and “strong end system”,
> > should probably be discussed in the IPv6 docs.
> 
> Seems to me that a “hosts that acts as routers” are routers.  It’s not some different class of device.  The definition from RFC8200 is:
> 
>    router       a node that forwards IPv6 packets not explicitly
>                 addressed to itself.  (See Note below.)
> 
>    host         any node that is not a router.  (See Note below.)
> 
>    ….
> 
>    Note: it is possible for a device with multiple interfaces to be
>    configured to forward non-self-destined packets arriving from some
>    set (fewer than all) of its interfaces and to discard non-self-
>    destined packets arriving from its other interfaces.  Such a device
>    must obey the protocol requirements for routers when receiving
>    packets from, and interacting with neighbors over, the former
>    (forwarding) interfaces.  It must obey the protocol requirements for
>    hosts when receiving packets from, and interacting with neighbors
>    over, the latter (non-forwarding) interfaces.
> 
> I don’t think changing these definitions in node requirements is appropriate.

I hear you, and I am not suggesting any change in the host and router
definitions. However, an end system that acts as both a router and a
host has to do something slightly different than an ordinary router
would.

If the end system receives a packet with a destination that does
not match one of its own delegated prefixes, it needs to drop the
packet and send "Destination Unreachable - No route to destination"
instead of forwarding the packet to another node (e.g., to a default
router). This is necessary to avoid a reflection attack where the attacker
attempts to abuse the end system by making it do work to forward
packets it should not be handling.

Whether/not you agree that the term "end system" should be used
to describe these, I still see value in importing the weak/strong ES
discussion from RFC11222 because the same concepts apply to IPv6.

Thanks - Fred
fred.l.templin@boeing.com

> Bob
> 
> >
> > Thanks - Fred
> >
> > From: Timothy Winters [mailto:twinters@iol.unh.edu]
> > Sent: Wednesday, September 20, 2017 7:56 AM
> > To: Templin, Fred L <Fred.L.Templin@boeing.com>
> > Cc: Tim Chown <Tim.Chown@jisc.ac.uk>; Russ White <russ@riw.us>; ipv6@ietf.org
> > Subject: Re: I-D Action: draft-ietf-6man-rfc6434-bis-01.txt
> >
> > Hi Fred,
> >
> > The first thing that came to mind reading your email is your are talking about a CE Router (RFC 7084).   Acts as a Host on the WAN, but
> a Router on the LAN interface.
> >
> > I would not be in favor of trying to document that behavior in node requirements.  I would prefer to keep it simple, or are you
> thinking of a case that's not covered in RFC 7084?
> >
> > Regards,
> > Tim
> >
> > On Wed, Sep 20, 2017 at 10:50 AM, Templin, Fred L <Fred.L.Templin@boeing.com> wrote:
> > Hi Tim,
> >
> > > -----Original Message-----
> > > From: Tim Chown [mailto:Tim.Chown@jisc.ac.uk]
> > > Sent: Wednesday, September 20, 2017 2:01 AM
> > > To: Templin, Fred L <Fred.L.Templin@boeing.com>
> > > Cc: ipv6@ietf.org; Russ White <russ@riw.us>
> > > Subject: Re: I-D Action: draft-ietf-6man-rfc6434-bis-01.txt
> > >
> > > Hi,
> > >
> > > > On 19 Sep 2017, at 18:23, Templin, Fred L <Fred.L.Templin@boeing.com> wrote:
> > > >
> > > > I realize that this goes back to the previous node requirements docs (RFC6434
> > > > and RFC4294), but shouldn't this document cite RFC1122 and RFC1812?
> > >
> > > RFC1122 could be added in the intro.
> > >
> > > I’d suggest RFC1812 could be reviewed/cited in draft-ietf-v6ops-ipv6rtr-reqs-00, something for Russ to consider.
> >
> > OK, thanks. One of the reasons I ask is because I think our IPv6 node/router
> > requirements documents are missing something important that appeared
> > in these earlier standards - the model of a host that also acts as a router.
> >
> > RFC1122 calls them "end systems", or "hosts with embedded gateway".
> > They host their own local applications and can also forward packets on
> > behalf of nodes connected to a downstream interface. The model has
> > significant implications for Internet of Things.
> >
> > Do we want to import that language into our IPv6 requirements docs?
> >
> > Thanks - Fred
> >
> > > Tim
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