This tries to scan all private IP range
CLASS A
10.0.0.0 - 10.255.255.255
CLASS B
172.16.0.0 - 172.31.255.255
CLASS C
192.168.0.0 - 192.168.255.255
Note you can find also other private IPs configured on some networks, but those ones have been reserved by IANA
EXECUTION EXAMPLE
$ ./privateIPscaner.sh -c C
IP class C selected
[+] Host 192.168.0.106 - ACTIVE
[+] Host 192.168.3.1 - ACTIVE
[+] Host 192.168.3.3 - ACTIVE