From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Saber zrelli" Subject: newbie question about kernel networking Date: Sat, 20 Mar 2004 22:06:11 +0900 Sender: netfilter-admin@lists.netfilter.org Message-ID: <1079787971.1673.183015624@webmail.messagingengine.com> References: <20040320002512.GC3373@salty> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20040320002512.GC3373@salty> Errors-To: netfilter-admin@lists.netfilter.org List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" To: netfilter@lists.netfilter.org hi people , my question is simple : if i use some packet injection library like libnet to send a packet from host A to host B , and libpcap to capture packets and monitor all network traffik. let's say i send TCP SYN packet (like if my host is establishing a TCP connection with host B ), the host may answer with a SYN packet accepting my connection , then two possibilities : 1 - the kernel will send RST packet to the host B coz the SYN packet from host B be is assimilated as connection establishment request to a non existant service. 2 - the libpcap tool im using acts as a service and the kernel just deliver the SYN packet from B to my sniffing tool without taking any action like in 1. in case 1 the kernel will generate an extra trafic i dont need . in case 2 it acts transparently. i think that case 2 is more correct , but i'm not sure. Any comments greatly appreciated. Regards. -- Saber Zrelli kanazawa university international house kakuma-machi , kanazawa , Ishikawa 920-1192 Japan.