Hi, I was trying to figure out how the rp_filter does the source address validation. I traced out the location in source code(2.4.18) to fib_validate_source() in net/ipv4/fib_frontend.c But here the line where I think the rp filter comes in rpf = IN_DEV_RPFILTER(in_dev); But this looks for the enabling of rp_filter for the all the interfaces and for the individual interfaces. Then comes the line if (rpf) goto e_inval; That means if rp filtering is enabled return EINVAL!!!!!! I seem to be missing a lot of things Could someon please help me out on this ? Regards KK _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/