hi Suppose I use libnet to inject packets into the kernel .. suppose they are tcp packets with a different src ip and dest ip from my machines ip .... which netfilter hook can i expect this packet to hit first ... the NF_IP_LOCAL_OUT or the NF_IP_PRE_ROUTING hook .. ? the netfilter unreliable guides state this "The NF_IP_LOCAL_OUT [5] hook is called for locally generated packets. Here You can see that routing occurs after this hook is called: in fact, the routing code is called first (to figure out the source IP address and some IP options), and called again if the packet is altered" Here what do we mean by "locally generated packets", the packets generated by that machines application (irrespective of what src and dest ip that packet carries) or the packets that have src_ip== that of this machine(irrespective of whether they were generated by applications on this machine or if they are coming from the network ??) Please explain. thanks Amit "DISCLAIMER: This message is proprietary to Hughes Software Systems Limited (HSS) and is intended solely for the use of the individual to whom it is addressed. It may contain privileged or confidential information and should not be circulated or used for any purpose other than for what it is intended. If you have received this message in error, please notify the originator immediately. If you are not the intended recipient, you are notified that you are strictly prohibited from using, copying, altering, or disclosing the contents of this message. HSS accepts no responsibility for loss or damage arising from the use of the information transmitted by this email including damage from virus."