traceroute failed.Specify protocal traceroute used manually to fix it.
Today, I ran the traceroute program on a machine running FreeBSD. It failed once and again. Traceroute complained: traceroute: sendto: Permission denied. So I tried to ping. Ping failed, too. I then checked out the configuration of the firewall, which actually denied the pass through of ICMP packet. So I set it to allow ICMP pacakges to pass through the firewall. Ping worked as I expected. But traceroute still failed. ...