IP Calculation
Useful tools to calculate subnets and ranges
The math behind IP addresses is convoluted. Our nice IPv4 addresses start out as 32-bit binary numbers, which are then converted to base 10 numbers in four 8-bit fields. Decimal numbers are easier to manage than long binary strings; still, calculating address ranges, netmasks, and subnets is a bit difficult and error-prone, except for the brainiacs who can do binary conversions in their heads. For the rest of us, meet ipcalc
and ipv6calc
.
ipcalc
is for IPv4 networks, and ipv6calc
is for IPv6 networks.
Calculate using subnet
Calculate using netmask
Classful IP Ranges
E.g Class A,B,C (depreciated)
Class
IP Address Range
Class A IP Address Range
0.0.0.0 - 127.255.255.255
Class B IP Address Range
128.0.0.0 - 191.255.255.255
Class C IP Address Range
192.0.0.0 - 223.255.255.255
Class D IP Address Range
224.0.0.0 - 239.255.255.255
Class E IP Address Range
240.0.0.0 - 255.255.255.255
IPv4 Private Address Ranges
Class
Range
Class A Private Address Range
10.0.0.0 - 10.255.255.255
Class B Private Address Range
172.16.0.0 - 172.31.255.255
Class C Private Address Range
192.168.0.0 - 192.168.255.255
Localhost Range
127.0.0.0 - 127.255.255.255
IPv4 Subnet Cheat Sheet
Subnet cheat sheet, not really related to pen testing but a useful reference.
CIDR
Decimal Mask
Number of Hosts
/31
255.255.255.254
1 Host
/30
255.255.255.252
2 Hosts
/29
255.255.255.249
6 Hosts
/28
255.255.255.240
14 Hosts
/27
255.255.255.224
30 Hosts
/26
255.255.255.192
62 Hosts
/25
255.255.255.128
126 Hosts
/24
255.255.255.0
254 Hosts
/23
255.255.254.0
512 Host
/22
255.255.252.0
1022 Hosts
/21
255.255.248.0
2046 Hosts
/20
255.255.240.0
4094 Hosts
/19
255.255.224.0
8190 Hosts
/18
255.255.192.0
16382 Hosts
/17
255.255.128.0
32766 Hosts
/16
255.255.0.0
65534 Hosts
/15
255.254.0.0
131070 Hosts
/14
255.252.0.0
262142 Hosts
/13
255.248.0.0
524286 Hosts
/12
255.240.0.0
1048674 Hosts
/11
255.224.0.0
2097150 Hosts
/10
255.192.0.0
4194302 Hosts
/9
255.128.0.0
8388606 Hosts
/8
255.0.0.0
16777214 Hosts
Last updated