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Re: [NANOG] Microsoft.com PMTUD black hole?

  • From: Tomas L. Byrnes
  • Date: Tue May 06 20:52:02 2008

Interestingly, Windows XP, Sp3, released today, describes changes in
PMTUD behavior.

Black Hole Router detection is now on by default:

http://download.microsoft.com/download/6/8/7/687484ed-8174-496d-8db9-f02
b40c12982/Overview%20of%20Windows%20XP%20Service%20Pack%203.pdf
 

> -----Original Message-----
> From: Robert Bonomi [mailto:[email protected]] 
> Sent: Tuesday, May 06, 2008 3:54 PM
> To: [email protected]
> Subject: Re: [NANOG] Microsoft.com PMTUD black hole?
> 
> `
> 
> > Date: Tue, 06 May 2008 14:29:03 -0700
> > From: Nathan Anderson/FSR <[email protected]>
> > Subject: Re: [NANOG] Microsoft.com PMTUD black hole?
> >
> >
> > Now, although that makes sense, in order to avoid issues 
> like the one 
> > we are facing with Microsoft, would it not make _more_ 
> sense for the 
> > stack to look at the PMTU cache first, and then adjust its own MSS 
> > just for connections to that one host?
> 
> This _is_ Microsoft we're talking about, remember.  'sense' 
> and 'Microsoft'
> are, at a =minimum= orthogonal to each other -- and may not 
> even inhabit the same address-space. <wry grin>
> 
> As for standards, it is official Microsoft policy to "embrace 
> and extend",
> not to implement in a way compatible with the rest of the 
> world.   *sigh*
> 
> I -don't- believe the rumor that "PMTUD/Vista Ultimate" sends 
> incrementally increasing-size packets, and uses the first one 
> that -doesn't- get through
> as the size limit.     <giggle>
> 
> 
> 
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