Hi,all When I use traceroute with loose source routing option, #traceroute -g middle-route-address host it gave the following error: traceroute:wrote 46 chars, ret=-1 *traceroute: sendto: Invalid argument traceroute:wrote 46 chars, ret=-1 *traceroute: sendto: Invalid argument ....... I wonder if someone has some experience and can give me some suggestion! Thanks in advance! Wei - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org