[e2e] 100% NAT - a DoS proof internet
Jon Crowcroft
Jon.Crowcroft at cl.cam.ac.uk
Mon Feb 13 05:46:39 PST 2006
In missive <3378EA87-1954-49F6-9CC8-8E91BD030650 at cisco.com>, Fred Baker typed:
>>Are you telling me that you think that devices that are behind NATs
>>don't get DOS'd?
not by address scanning worms, no...
>>I would prefer that you used the term "stateful firewall" as compared
>>to "NAT"; NATs aren't necessarily stateful, and stateful firewall
>>technology doesn't require network address translation to make it
>>work. If the mapping between an interior address and an exterior
>>address is predictable, the device behind can be DOS'd; the thing
>>that a stateful firewall does is make the attack a bit harder to
>>perpetrate.
sure - so what i was proposing was a
rendezvous mechanism for src/dst
pairs of nodes and their globally reachable address allocation - so
it can't be DOS'd normally,
as it aint there, but temporally,
and it aint there for anyone other than
for this pair (multicast, tbd:) spatially
i.e. ultra stateful (think of it as a VCI allocation mechanism with a
capability:)
>>Let me give you a simplistic example. If I have a SIP Proxy in a NAT
>>system, so that SIP is made to traverse the firewall in a
>>straightforward manner, SIP can then be used as an attack vector to
>>the device it proxies for. That is but one.
yes, in today's internet, but not in what i propose
>>On Feb 13, 2006, at 6:49 AM, Jon Crowcroft wrote:
>>
>>> So there's three things here
>>>
>>> 1/ a mad idea for a DoS proof internet - This goes like this:
>>>
>>> What if 100% of hosts were behing a NAT (a bit like mark handley and
>>> adam greenhalgh's idea on a dos proof internet in fdna a while back,
>>> but taken to extreme, or also like default off paper in hotnets)
>>>
>>> So how would you ever reach someone (like most NAT traversal stuff is
>>> tricky - viz skype - see also below:)
>>>
>>> Meanwhile, here is how: Distributed Hashed Time.
>>>
>>> So we all know about DHTs - they hash an object to a node id, then use
>>> some p2p route to get to the node id (e.g. MIT's chord finger table
>>> etc etc).
>>>
>>> So if we want to talk to a set of known people, we hash their
>>> identifier (name) to TIME. We then send to each other at that agreed
>>> time - no-one else can send to us or from us to them, and the hash key
>>> can be a shared secret....
>>>
>>> there you go...the details should be simple (apart from how you
>>> provide sufficiently accurate synchronized time without a globally
>>> reachable adddress betweewn the NTP servers, which, I admit, is
>>> probably a mite tricky - i guess you need to have them agree a set of
>>> rough times or something:)
>>>
>>> 2/ a pointer to something about a mad bad idea i had about control
>>> networks
>>> http://www.cl.cam.ac.uk/~jac22/press-release-backstory.htm
>>>
>>> 3/ a reminder of a workshop deadline - sorry:)
>>> (see website for more info on submissions)
>>>
>>> ------------------------------------------------------------------
>>> PAPER SUBMISSION DEADLINE HAS BEEN EXTENDED TO
>>> 26 FEBRUARY 2006
>>> ------------------------------------------------------------------
>>>
>>> CALL FOR PAPERS
>>>
>>> Second International Workshop on
>>> Multi-hop Ad hoc Networks: from theory to reality
>>> REALMAN 2006
>>> http://www.cl.cam.ac.uk/realman
>>>
>>>
>>> cheers
>>>
>>> jon
cheers
jon
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