[ipv6hackers] Win7 - no managed flag, DHCP address released?!?

Marc Heuse mh at mh-sec.de
Thu Oct 18 17:58:09 CEST 2012

if this is true, then it is a great DOS opportunity and I am sure one
can come up with some clever ideas what else to do with that.

Sadly I can not test anything for some more days until I have a decent
internet connection, then I will try this.


Am 18.10.2012 15:33, schrieb Karl Auer:
> [I sent this to the IETF list and they suggested I repost it here.]
> I have just seen the following demonstrated.
> Two routers, short RA interval, both sending RAs for the same prefix,
> both with the autoconf flag set, one with the managed flag set and one
> without.
> A Windows 7 host gets an address via DHCPv6 when the RA with the managed
> flag comes around - and DROPS IT when an RA without the managed flag
> comes past.
> This is not the valid lifetime expiring normally. I was not able to
> determine whether the Windows host is actually sending a DHCPv6 release
> as well, but it is most certainly dropping the address from the
> interface.
> I will be trying to do my own tests to confirm (or not) this behaviour,
> but has anyone else seen it? Or seen it with other operating systems?
> If it is indeed happening, this behaviour seems very badly broken to me.
> I don't feel the relevant RFCs can reasonably be interpreted as
> supporting this behaviour.
> Regards, K.

Marc Heuse

PGP: FEDD 5B50 C087 F8DF 5CB9  876F 7FDD E533 BF4F 891A

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