One of the ways to map a targeted network for live hosts is by sending an ICMP ECHO request to the broadcast or the network address. The request would be broadcasted to all hosts on the targeted network. The live hosts will send an ICMP ECHO Reply to the attacker’s source IP address.
You send a ping request to the broadcast address 192.168.5.255.
[root@ceh/root]# ping -b 192.168.5.255
WARNING: pinging broadcast address
PING 192.168.5.255 (192.168.5.255) from 192.168.5.1 : 56(84) bytes of data. 64 bytes from 192.168.5.1: icmp_seq=0 ttl=255 time=4.1 ms 64 bytes from 192.168.5.5: icmp_seq=0 ttl=255 time=5.7 ms —
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There are 40 computers up and running on the target network. Only 13 hosts send a reply while others do not. Why?