diff -up arptables_jf-0.0.8/arptables.c.mangle arptables_jf-0.0.8/arptables.c --- arptables_jf-0.0.8/arptables.c.mangle 2010-03-25 11:18:07.351682117 +0100 +++ arptables_jf-0.0.8/arptables.c 2010-03-25 11:19:07.730682571 +0100 @@ -1978,6 +1978,8 @@ int do_commandarp(int argc, char *argv[] check_inverse ( optarg, &invert, &optind, argc ); set_option ( &options, OPT_ARHLN, &fw.arp.invflags, invert ); arhln = argv[optind - 1]; + if ( arhln ) + parse_uint8 ( arhln, &fw.arp.arhln, &fw.arp.arhln_mask ); break; case 'p':