[NANOG] Microsoft.com PMTUD black hole?

Wed May 7 21:19:59 UTC 2008

On 7 mei 2008, at 23:08, Nathan Anderson/FSR wrote:

> How so?  Iljitsch is suggesting that ICMP blockers originate packets
> without DF set if they are going to block the ICMP messages that PMTUD
> needs in order to work in the first place.  That's what (I think) he
> means by "disabling path MTU discovery."

Yes.

> Also, for some reason, as I pointed out before, XP black hole router
> discovery doesn't seem to be working for me for whatever reason.  Does
> anybody have any clue why that might be the case?

The problem is in the direction from M$ to you, so you can't fix that  
from your end. I wonder if they've installed SP3 on their servers...