Messages in this thread | | | Date | Thu, 07 Feb 2013 11:29:08 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect |
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On 02/07/2013 10:44 AM, Kees Cook wrote: >> >> This patch probably also breaks TCP STUNT that is used by some applications for NAT >> traversal. > > The patch would not break it -- it defaults the sysctl to staying enabled. > > If you mean the documentation should be updated, sure, that's easy to do. > > David: I know you aren't a fan of this patch, but I'd like to try to > convince you. :) This leaves the feature enabled and add a toggle for > systems (like Chrome OS) that don't want to risk this DoS at all. > There are so very many other toggle, I don't see why this one would be > a problem to add. >
It is not just STUNT, but in NAT-less configurations behind stateful firewalls (which is expected to be the norm for IPv6), TCP rendezvous via crossed SYN is a very effective way to establish peer-to-peer connections.
-hpa
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