Acceptable prefix sizes for Windows Vista/7

Frank Bulk frnkblk at
Wed Feb 16 06:51:31 CET 2011

Thanks.  Sounds like Netgear has to fix that, then.  They've already been informed.  They probably only ever tested with PDs of /64.


-----Original Message-----
From: Erik Kline [mailto:ek at] 
Sent: Tuesday, February 15, 2011 11:27 PM
To: frnkblk at
Cc: ipv6-ops at
Subject: Re: Acceptable prefix sizes for Windows Vista/7

> Does Windows possibly have a requirement that the advertised prefix only be a /64 in order for SLAAC to work?

I would think that this would be the expected behaviour actually.  I
would be surprised if other operating systems didn't behave similarly
for Ethernet interfaces.

I see that says you
can do math (128 -n), but it looks like this paragraph may be trumping
things, since EUI-64s are, well, 64bits:

    If the sum of the prefix length and interface identifier length
does not equal 128 bits, the Prefix Information option MUST be

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