Hello all, thx for the answers right now. I am very sorry, I obviously made a mistake. ip_send() is included in the 2.4.x Kernel (according to the Cross-Referencing Linux project). Kernel 2.4.26: http://lxr.linux.no/ident?v=2.4.26;i=ip_send But, again according to lxr, it is NOT USED in Kernel 2.6.x (http://lxr.linux.no/ident?v=2.6.5;i=ip_send). Did some research this afternoon and found the following. Obviously ip_send was replaced by dst_output() in the 2.5.45 Kernel. ChangeLog-2.5.45: ... <kuznet@xxxxxxxxxxxxx> [IPV4]: Kill ip_send, use dst_output instead. ... You find more information about dst_output at http://lxr.linux.no/ident?v=2.6.0;i=dst_output So if you are interested in more informations use the link above! Thx a lot guys for your answers! Cheers, Markus -----Original Message----- From: netfilter-admin@xxxxxxxxxxxxxxxxxxx [mailto:netfilter-admin@xxxxxxxxxxxxxxxxxxx] On Behalf Of Markus Zeilinger Sent: Donnerstag, 13. Mai 2004 13:56 To: netfilter Subject: ip_send() function Dear all, I am currently writing a paper for my studies about netfilter and Linux Firewalling. In this case I also write a chapter about packet handling through the Linux network stack. Several papers and also in Harald Welte's "The journey of a packet through the linux 2.4 network stack" mention a function ip_send() in the process of packet forwarding. According to Harald this function is defined in /include/net/ip.h. But I cannot find a definition there, and surprisingly I was not able to find the ip_send() function anywhere in the kernel source. I searched through Kernel 2.6.6, 2.4.6 and 2.4.0 but did not find any tracks of a ip_send() function!?! Can you help me with this problem? Sorry if this is a stupid question, but I am a newbie in Linux networking. ;-) Thx a lot for your assistence! best regards, Markus ------------------------------------------------ Markus Zeilinger Institute for Systems Engineering and Automation University of Linz Altenberger Strasse 69 A-4040 Linz, AUSTRIA Tel.: +43-(0)732-2468-8869 Fax: +43-(0)732-2468-8878 Mail: mz@xxxxxxxxxxxxxxxxxx