A.burpsuite B.Nmap C.XueTr D.X-Scan
A.3-4-2 B.3-1-2 C.3-2-1 D.1-2-4
A.echo0>/proc/sys/net/ipv4/icmp_echo_ignore_all B.echo1>/proc/sys/net/ipv4/icmp_echo_ignore_all C.echo0>/proc/sys/net/ipv4/tcp_syncookies D.echo1>/proc/sys/net/ipv4/tcp_syncookies