Messages in this thread |  | | Date | Wed, 11 Dec 2013 12:26:37 -0800 | From | Stephen Hemminger <> | Subject | Re: [PATCH] TCP: add option for silent port knocking with integrity protection |
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On Wed, 11 Dec 2013 21:19:00 +0100 Christian Grothoff <grothoff@in.tum.de> wrote:
> On 12/11/2013 09:01 PM, David Miller wrote: > > From: Christian Grothoff <grothoff@in.tum.de> > > Date: Tue, 10 Dec 2013 19:35:36 +0100 > > > >> Only NAT implementations that change the SQN are not supported > >> (those should be rare, but we have no hard data on this). > > > > Even Linux's netfilter can and does do this, it is absolutely necessary > > for tracking SIP and FTP protocols, and it's also used in our virtual > > server load balancing modules. > > > > We're aware that Linux _can_ do this. I was not aware it was doing this > for > SIP and FTP specifically; regardless, what implementations can do is less > important than what they are configured to do most of the time, and that's > what we'd need hard data on. Anyway, I'd be very interested to learn how > you use this for SIP/FTP to evaluate the impact. Do you have documentation > on this? > > As for server load balancing, I suspect that those are not the kinds of > services that one would typically use port knocking for. Still, again a > good hint as to where trouble might lurk (and we will definitively include > those points in the next revision of the documentation).
The point is that doing it outside of TCP core is safer, less error prone and more flexible.
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