Hi, Assuming I have two IP Adresses (source and destination). How can I find out, wether I have to use the same interface for both. I consider to modify the arp_filter() function (in /usr/src/linux/net/ipv4/arp.c) to make it check wether the Source and Destination IP come from the same Interface. Igor -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/