Re: [pmtud] Minutes for PMTUD at IETF60

[Michael Welzl <Michael.Welzl at uibk.ac.at>]

Dear all,

I would like to comment on this part of the proceedings
(related to my proposal, draft-welzl-pmtud-options-01.txt):


> Krishnan noted a problem with the TTL check proposed in the draft: while
> the probability of guessing TTL is less than one in 256, most OS's
> set it to some known lower value (32, 64).  It's not random.  So the
> window in which you need to guess becomes much smaller.

In San Diego, I answered this question with "yes, you're
right". Actually, my answer was wrong - I'm sorry
for this. In the heat of the action, I forgot how this
problem was solved (I don't say "how I solved this problem",
because I actually borrowed the TTL-Nonce-combination from
the quick-start draft), but if you look at the draft, you'll
see that TTL-Check is set to a random value, not TTL.

The probability really IS 1 out of 256.

Sorry folks,

cheers,
Michael



Zitat von Matthew J Zekauskas <matt at internet2.edu>:

> Attached.  In addition, these minutes and all presentations
> are available off of
> http://people.internet2.edu/~matt/pmtud/meetings/ietf60/
> 
> --Matt
> 




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