Для объяснения..

A Ping sweep is a technique used to determine which of a range of IP addresses map to live hosts. It consists of ICMP ECHO requests sent to multiple hosts. If a given address is live, it will return an ICMP ECHO reply.

A ping is often used to check that a network device is functioning. To disable ping sweeps on a network, administrators can block ICMP ECHO requests from outside sources. However, ICMP TIMESTAMP and Address Mask Requests can be used in a similar manner.