Dear list, thanks to googling and RTFMing and some very instructive graphics, I think I have understood the netfilter packet flow in principle. But all material I have found only seems to describe the journey of packets which really come from the "outside" or go to the "outside". I would be strongly interested in some documentation describing what happens to packets that are internally generated and absorbed. For example, even with one NIC and one IP address, there are packets going from the IP address to loopback and vice versa, so the packets are generated locally and received locally. According to my testing so far (linux kernel 2.6.26 / debian lenny), the behaviour of these packets seems to contradict the documents and graphics I have seen. Such packets seem to go through the INPUT and OUTPUT chains of the FILTER table and through one or two chains of the NAT table (I just can't remember exactly at the moment), but not through the PREROUTING chain of the NAT table. This is confusing ... I would be grateful if somebody could give a comprehensive explanation of that or a hint regarding further documentation. By the way, the graphics I have mentioned are: http://jengelh.medozas.de/images/nf-packet-flow.png http://dmiessler.com/images/DM_NF.PNG http://linux-ip.net/nf/nfk-traversal.png http://ebtables.sourceforge.net/br_fw_ia/PacketFlow.png http://xkr47.outerspace.dyndns.org/netfilter/packet_flow/packet_flow10.png Perhaps it would be sufficient for understanding if somebody, refering to the first of these graphics, could just explain which part of the graph "purely internal" packets have to travel through. Thank you very much, Peter -- GMX.at - Österreichs FreeMail-Dienst mit über 2 Mio Mitgliedern E-Mail, SMS & mehr! Kostenlos: http://portal.gmx.net/de/go/atfreemail -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
