Your IP address:
Provider:
...

For example: 54.224.124.217

/
Input
Address: 3.5.21.0
Netmask: 255.255.255.0 = 24
Inversion mask: 0.0.0.255
Binary: 00000011.00000101.00010101.00000000
Reserved: No
Result
Network: 3.5.21.0/24 (Class A)
First IP: 3.5.21.1
Last IP: 3.5.21.254
Broadcast: 3.5.21.255
Network range: 3.5.21.0 - 3.5.21.255
List of all IP addresses: 3_5_21_0-24.txt
Number of hosts: 254
Number of IP addresses: 256