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From: "Ric Messier" <kilroy@WasHere.COM>
To: 'Martijn Lievaart' <m@rtij.nl>
Cc: netfilter@lists.netfilter.org
Subject: RE: syn DDoS attack solution
Date: Fri, 1 Jun 2007 15:38:12 -0600	[thread overview]
Message-ID: <013901c7a495$2890f760$79b2e620$@COM> (raw)
In-Reply-To: <466090CA.2050806@rtij.nl>

Martijn Lievaart writes:
> 
> Ric Messier wrote:
> > Then your original description was incorrect or at least inadequate.
> It has
> > nothing to do with SYN as originally suggested since an ESTABLISHED
> > connection has blown past SYN, through SYN/ACK and by ACK. It has
> completed
> > the TCP handshake, as you note above. A SYN attack/flood would stop
> after
> > sending the initial SYN and leave the connection half-open to exhaust
> the
> > half-open buffers.
> >
> 
> An connection is in the ESTABLISHED state once a packet has been seen.
> So once the SYN is seen, the state is ESTABLISHED.
> 

Not last time I checked. That may be true to some degree in iptables but in
netstat, an ESTABLISHED connection is one that has made it through the
handshake process. Otherwise, it's in SYN_RECV state. 

Ric




  parent reply	other threads:[~2007-06-01 21:38 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-31 16:19 syn DDoS attack solution Bgs
2007-05-31 19:57 ` R. DuFresne
2007-06-01  9:45   ` Bgs
2007-05-31 20:08 ` Ric Messier
2007-06-01  1:20   ` Tony.Ho
2007-06-01  9:44   ` Bgs
2007-06-01 15:01     ` Ric Messier
2007-06-01 15:37       ` Bgs
2007-06-02 19:07         ` R. DuFresne
2007-06-04 14:22           ` Ric Messier
2007-06-04 17:24           ` Martin McKeay
2007-06-04 23:16             ` R. DuFresne
2007-06-05  8:29             ` Bgs
2007-06-05 14:16               ` Steven M Campbell
2007-06-05 15:22                 ` ..prevention, was: " Arnt Karlsen
     [not found]                   ` <466583F4.8080107@SCampbell.net>
2007-06-05 15:40                     ` Steven M Campbell
2007-06-05 18:34                       ` Arnt Karlsen
2007-06-07 18:41                     ` Martin McKeay
2007-06-08  1:40                       ` Arnt Karlsen
2007-06-12 18:10                       ` Martin McKeay
2007-06-12 22:44                         ` R. DuFresne
2007-06-13 14:24                           ` Martin McKeay
2007-06-13 17:26                             ` Arnt Karlsen
2007-06-13 17:44                               ` Martin McKeay
2007-06-14 19:43                                 ` R. DuFresne
2007-06-14 20:13                                   ` supportnew
2007-06-01 21:34       ` Martijn Lievaart
2007-06-01 21:37         ` Martijn Lievaart
2007-06-01 21:38         ` Ric Messier [this message]
2007-06-01 23:09         ` Ethy H. Brito
2007-06-19 18:22         ` R. DuFresne
2007-06-19 22:19           ` Robert Nichols
2007-06-19 23:02             ` Pascal Hambourg
2007-06-21 18:26             ` R. DuFresne

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