From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ramin Alidousti Subject: Re: detection of the third tcp packet in a tcp connection setup Date: Thu, 27 Jun 2002 16:31:30 -0400 Sender: netfilter-admin@lists.samba.org Message-ID: <20020627203130.GC31466@cannon.eng.us.uu.net> References: <20020627194405.GLHF295.mta03-svc.ntlworld.com@there> <20020627195742.GA31466@cannon.eng.us.uu.net> <20020627200655.VZLE19225.mta07-svc.ntlworld.com@there> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20020627200655.VZLE19225.mta07-svc.ntlworld.com@there> Errors-To: netfilter-admin@lists.samba.org List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Antony Stone Cc: netfilter@lists.samba.org On Thu, Jun 27, 2002 at 09:06:54PM +0100, Antony Stone wrote: > On Thursday 27 June 2002 8:57 pm, Ramin Alidousti wrote: > > > If I'm not wrong you can always send data even in SYN and SYN/ACK. > > Like Patrick said the default options in the socket interface might > > not do it but I thought I saw some tweaking in one of Richard Steven's > > (god bless his soul) books to push traffic in SYN packets. > > Is that an interesting way to get round packet filtering firewalls ? Why? The fw would either block the SYN (in case of DENY) or let the SYN and any subsequent packet through... > Send enough data (eg an http request) in a SYN packet so that the application > does the dirty work for you, even if the packet filter isn't going to allow > the connection to get ESTABLISHED ? Again, if the SYN gets through, it's very likely that the connection will get ESTABLISHED. > Or do you have to fiddle with the receiving socket too in order for it to > cope with this ? Good question. dunno. Ramin > Antony.