Re: Regarding pre-round trip for stateless cookie (Jan's issue)

[Michael Richardson <mcr@sandelman.ottawa.on.ca>]

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>>>>> "Radia" == Radia Perlman <- Boston Center for Networking <Radia.Perlman@sun.com>> writes:
    Radia> Just because I had to read the above a few times before I
    Radia> understood what 
    Radia> he was saying, I thought I'd restate it in my own words.

    Radia> What he's saying is that with the "4/6" design, if it's hard for
    Radia> Bob to make a decision about whether he thinks he's under attack,
    Radia> then he can always assume he's under attack, and always do the
    Radia> 6-message exchange.

  I am of the opinion that for any system which has a non-trivial number
of defined connections, that it pretty much impossible for Bob to determine
that he isn't under attack.

  The only deployments that I can see that could determine for certain
that they aren't under attack would be two or three node VPNs.

  The moment you add even half a dozen road warriors, or in FreeSWAN's case, 
2^32 potential OE connections, one might as well assume one is under attack.

  As such, I question any design that introduces complexity to optomize the
unusual case.  I would rather have shorter setups times, but I would rather
it was resistant to DDoS.

]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] mcr@sandelman.ottawa.on.ca http://www.sandelman.ottawa.on.ca/ |device driver[
] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); [
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