Find IP IPv4 Network/Subnet and its host address ranges

What is an IPv4 IP address its network and host address ranges?

An IPv4 IP address is an address used in order to uniquely identify a device on an IP network. The address is made up of 32 binary bits, which can be divisible into a network portion and host portion with the help of a subnet mask. The 32 binary bits are broken into four octets (1 octet = 8 bits). Each octet is converted to decimal and separated by a period (dot).

How to Subnet IPv4? Its simple answer is that subnetting is the process of taking a network and splitting it into smaller networks, known as subnets. It's used to free up more public IPv4 addresses and segment networks for security and easier management.
Following are the ranges of IPv4 subnet/network address and their host addresses.

IPv4 AddressIPv6 Address
251.21.15.1 0:0:0:0:0:ffff:fb15:f01
251.21.15.2 0:0:0:0:0:ffff:fb15:f02
251.21.15.3 0:0:0:0:0:ffff:fb15:f03
251.21.15.4 0:0:0:0:0:ffff:fb15:f04
251.21.15.5 0:0:0:0:0:ffff:fb15:f05
251.21.15.6 0:0:0:0:0:ffff:fb15:f06
251.21.15.7 0:0:0:0:0:ffff:fb15:f07
251.21.15.8 0:0:0:0:0:ffff:fb15:f08
251.21.15.9 0:0:0:0:0:ffff:fb15:f09
251.21.15.10 0:0:0:0:0:ffff:fb15:f0a
251.21.15.11 0:0:0:0:0:ffff:fb15:f0b
251.21.15.12 0:0:0:0:0:ffff:fb15:f0c
251.21.15.13 0:0:0:0:0:ffff:fb15:f0d
251.21.15.14 0:0:0:0:0:ffff:fb15:f0e
251.21.15.15 0:0:0:0:0:ffff:fb15:f0f
251.21.15.16 0:0:0:0:0:ffff:fb15:f10
251.21.15.17 0:0:0:0:0:ffff:fb15:f11
251.21.15.18 0:0:0:0:0:ffff:fb15:f12
251.21.15.19 0:0:0:0:0:ffff:fb15:f13
251.21.15.20 0:0:0:0:0:ffff:fb15:f14
251.21.15.21 0:0:0:0:0:ffff:fb15:f15
251.21.15.22 0:0:0:0:0:ffff:fb15:f16
251.21.15.23 0:0:0:0:0:ffff:fb15:f17
251.21.15.24 0:0:0:0:0:ffff:fb15:f18
251.21.15.25 0:0:0:0:0:ffff:fb15:f19
251.21.15.26 0:0:0:0:0:ffff:fb15:f1a
251.21.15.27 0:0:0:0:0:ffff:fb15:f1b
251.21.15.28 0:0:0:0:0:ffff:fb15:f1c
251.21.15.29 0:0:0:0:0:ffff:fb15:f1d
251.21.15.30 0:0:0:0:0:ffff:fb15:f1e
251.21.15.31 0:0:0:0:0:ffff:fb15:f1f
251.21.15.32 0:0:0:0:0:ffff:fb15:f20
251.21.15.33 0:0:0:0:0:ffff:fb15:f21
251.21.15.34 0:0:0:0:0:ffff:fb15:f22
251.21.15.35 0:0:0:0:0:ffff:fb15:f23
251.21.15.36 0:0:0:0:0:ffff:fb15:f24
251.21.15.37 0:0:0:0:0:ffff:fb15:f25
251.21.15.38 0:0:0:0:0:ffff:fb15:f26
251.21.15.39 0:0:0:0:0:ffff:fb15:f27
251.21.15.40 0:0:0:0:0:ffff:fb15:f28
251.21.15.41 0:0:0:0:0:ffff:fb15:f29
251.21.15.42 0:0:0:0:0:ffff:fb15:f2a
251.21.15.43 0:0:0:0:0:ffff:fb15:f2b
251.21.15.44 0:0:0:0:0:ffff:fb15:f2c
251.21.15.45 0:0:0:0:0:ffff:fb15:f2d
251.21.15.46 0:0:0:0:0:ffff:fb15:f2e
251.21.15.47 0:0:0:0:0:ffff:fb15:f2f
251.21.15.48 0:0:0:0:0:ffff:fb15:f30
251.21.15.49 0:0:0:0:0:ffff:fb15:f31
251.21.15.50 0:0:0:0:0:ffff:fb15:f32
251.21.15.51 0:0:0:0:0:ffff:fb15:f33
251.21.15.52 0:0:0:0:0:ffff:fb15:f34
251.21.15.53 0:0:0:0:0:ffff:fb15:f35
251.21.15.54 0:0:0:0:0:ffff:fb15:f36
251.21.15.55 0:0:0:0:0:ffff:fb15:f37
251.21.15.56 0:0:0:0:0:ffff:fb15:f38
251.21.15.57 0:0:0:0:0:ffff:fb15:f39
251.21.15.58 0:0:0:0:0:ffff:fb15:f3a
251.21.15.59 0:0:0:0:0:ffff:fb15:f3b
251.21.15.60 0:0:0:0:0:ffff:fb15:f3c


251.21.15.61 0:0:0:0:0:ffff:fb15:f3d
251.21.15.62 0:0:0:0:0:ffff:fb15:f3e
251.21.15.63 0:0:0:0:0:ffff:fb15:f3f
251.21.15.64 0:0:0:0:0:ffff:fb15:f40
251.21.15.65 0:0:0:0:0:ffff:fb15:f41
251.21.15.66 0:0:0:0:0:ffff:fb15:f42
251.21.15.67 0:0:0:0:0:ffff:fb15:f43
251.21.15.68 0:0:0:0:0:ffff:fb15:f44
251.21.15.69 0:0:0:0:0:ffff:fb15:f45
251.21.15.70 0:0:0:0:0:ffff:fb15:f46
251.21.15.71 0:0:0:0:0:ffff:fb15:f47
251.21.15.72 0:0:0:0:0:ffff:fb15:f48
251.21.15.73 0:0:0:0:0:ffff:fb15:f49
251.21.15.74 0:0:0:0:0:ffff:fb15:f4a
251.21.15.75 0:0:0:0:0:ffff:fb15:f4b
251.21.15.76 0:0:0:0:0:ffff:fb15:f4c
251.21.15.77 0:0:0:0:0:ffff:fb15:f4d
251.21.15.78 0:0:0:0:0:ffff:fb15:f4e
251.21.15.79 0:0:0:0:0:ffff:fb15:f4f
251.21.15.80 0:0:0:0:0:ffff:fb15:f50
251.21.15.81 0:0:0:0:0:ffff:fb15:f51
251.21.15.82 0:0:0:0:0:ffff:fb15:f52
251.21.15.83 0:0:0:0:0:ffff:fb15:f53
251.21.15.84 0:0:0:0:0:ffff:fb15:f54
251.21.15.85 0:0:0:0:0:ffff:fb15:f55
251.21.15.86 0:0:0:0:0:ffff:fb15:f56
251.21.15.87 0:0:0:0:0:ffff:fb15:f57
251.21.15.88 0:0:0:0:0:ffff:fb15:f58
251.21.15.89 0:0:0:0:0:ffff:fb15:f59
251.21.15.90 0:0:0:0:0:ffff:fb15:f5a
251.21.15.91 0:0:0:0:0:ffff:fb15:f5b
251.21.15.92 0:0:0:0:0:ffff:fb15:f5c
251.21.15.93 0:0:0:0:0:ffff:fb15:f5d
251.21.15.94 0:0:0:0:0:ffff:fb15:f5e
251.21.15.95 0:0:0:0:0:ffff:fb15:f5f
251.21.15.96 0:0:0:0:0:ffff:fb15:f60
251.21.15.97 0:0:0:0:0:ffff:fb15:f61
251.21.15.98 0:0:0:0:0:ffff:fb15:f62
251.21.15.99 0:0:0:0:0:ffff:fb15:f63
251.21.15.100 0:0:0:0:0:ffff:fb15:f64
251.21.15.101 0:0:0:0:0:ffff:fb15:f65
251.21.15.102 0:0:0:0:0:ffff:fb15:f66
251.21.15.103 0:0:0:0:0:ffff:fb15:f67
251.21.15.104 0:0:0:0:0:ffff:fb15:f68
251.21.15.105 0:0:0:0:0:ffff:fb15:f69
251.21.15.106 0:0:0:0:0:ffff:fb15:f6a
251.21.15.107 0:0:0:0:0:ffff:fb15:f6b
251.21.15.108 0:0:0:0:0:ffff:fb15:f6c
251.21.15.109 0:0:0:0:0:ffff:fb15:f6d
251.21.15.110 0:0:0:0:0:ffff:fb15:f6e
251.21.15.111 0:0:0:0:0:ffff:fb15:f6f
251.21.15.112 0:0:0:0:0:ffff:fb15:f70
251.21.15.113 0:0:0:0:0:ffff:fb15:f71
251.21.15.114 0:0:0:0:0:ffff:fb15:f72
251.21.15.115 0:0:0:0:0:ffff:fb15:f73
251.21.15.116 0:0:0:0:0:ffff:fb15:f74
251.21.15.117 0:0:0:0:0:ffff:fb15:f75
251.21.15.118 0:0:0:0:0:ffff:fb15:f76
251.21.15.119 0:0:0:0:0:ffff:fb15:f77
251.21.15.120 0:0:0:0:0:ffff:fb15:f78


251.21.15.121 0:0:0:0:0:ffff:fb15:f79
251.21.15.122 0:0:0:0:0:ffff:fb15:f7a
251.21.15.123 0:0:0:0:0:ffff:fb15:f7b
251.21.15.124 0:0:0:0:0:ffff:fb15:f7c
251.21.15.125 0:0:0:0:0:ffff:fb15:f7d
251.21.15.126 0:0:0:0:0:ffff:fb15:f7e
251.21.15.127 0:0:0:0:0:ffff:fb15:f7f
251.21.15.128 0:0:0:0:0:ffff:fb15:f80
251.21.15.129 0:0:0:0:0:ffff:fb15:f81
251.21.15.130 0:0:0:0:0:ffff:fb15:f82
251.21.15.131 0:0:0:0:0:ffff:fb15:f83
251.21.15.132 0:0:0:0:0:ffff:fb15:f84
251.21.15.133 0:0:0:0:0:ffff:fb15:f85
251.21.15.134 0:0:0:0:0:ffff:fb15:f86
251.21.15.135 0:0:0:0:0:ffff:fb15:f87
251.21.15.136 0:0:0:0:0:ffff:fb15:f88
251.21.15.137 0:0:0:0:0:ffff:fb15:f89
251.21.15.138 0:0:0:0:0:ffff:fb15:f8a
251.21.15.139 0:0:0:0:0:ffff:fb15:f8b
251.21.15.140 0:0:0:0:0:ffff:fb15:f8c
251.21.15.141 0:0:0:0:0:ffff:fb15:f8d
251.21.15.142 0:0:0:0:0:ffff:fb15:f8e
251.21.15.143 0:0:0:0:0:ffff:fb15:f8f
251.21.15.144 0:0:0:0:0:ffff:fb15:f90
251.21.15.145 0:0:0:0:0:ffff:fb15:f91
251.21.15.146 0:0:0:0:0:ffff:fb15:f92
251.21.15.147 0:0:0:0:0:ffff:fb15:f93
251.21.15.148 0:0:0:0:0:ffff:fb15:f94
251.21.15.149 0:0:0:0:0:ffff:fb15:f95
251.21.15.150 0:0:0:0:0:ffff:fb15:f96
251.21.15.151 0:0:0:0:0:ffff:fb15:f97
251.21.15.152 0:0:0:0:0:ffff:fb15:f98
251.21.15.153 0:0:0:0:0:ffff:fb15:f99
251.21.15.154 0:0:0:0:0:ffff:fb15:f9a
251.21.15.155 0:0:0:0:0:ffff:fb15:f9b
251.21.15.156 0:0:0:0:0:ffff:fb15:f9c
251.21.15.157 0:0:0:0:0:ffff:fb15:f9d
251.21.15.158 0:0:0:0:0:ffff:fb15:f9e
251.21.15.159 0:0:0:0:0:ffff:fb15:f9f
251.21.15.160 0:0:0:0:0:ffff:fb15:fa0
251.21.15.161 0:0:0:0:0:ffff:fb15:fa1
251.21.15.162 0:0:0:0:0:ffff:fb15:fa2
251.21.15.163 0:0:0:0:0:ffff:fb15:fa3
251.21.15.164 0:0:0:0:0:ffff:fb15:fa4
251.21.15.165 0:0:0:0:0:ffff:fb15:fa5
251.21.15.166 0:0:0:0:0:ffff:fb15:fa6
251.21.15.167 0:0:0:0:0:ffff:fb15:fa7
251.21.15.168 0:0:0:0:0:ffff:fb15:fa8
251.21.15.169 0:0:0:0:0:ffff:fb15:fa9
251.21.15.170 0:0:0:0:0:ffff:fb15:faa
251.21.15.171 0:0:0:0:0:ffff:fb15:fab
251.21.15.172 0:0:0:0:0:ffff:fb15:fac
251.21.15.173 0:0:0:0:0:ffff:fb15:fad
251.21.15.174 0:0:0:0:0:ffff:fb15:fae
251.21.15.175 0:0:0:0:0:ffff:fb15:faf
251.21.15.176 0:0:0:0:0:ffff:fb15:fb0
251.21.15.177 0:0:0:0:0:ffff:fb15:fb1
251.21.15.178 0:0:0:0:0:ffff:fb15:fb2
251.21.15.179 0:0:0:0:0:ffff:fb15:fb3
251.21.15.180 0:0:0:0:0:ffff:fb15:fb4


251.21.15.181 0:0:0:0:0:ffff:fb15:fb5
251.21.15.182 0:0:0:0:0:ffff:fb15:fb6
251.21.15.183 0:0:0:0:0:ffff:fb15:fb7
251.21.15.184 0:0:0:0:0:ffff:fb15:fb8
251.21.15.185 0:0:0:0:0:ffff:fb15:fb9
251.21.15.186 0:0:0:0:0:ffff:fb15:fba
251.21.15.187 0:0:0:0:0:ffff:fb15:fbb
251.21.15.188 0:0:0:0:0:ffff:fb15:fbc
251.21.15.189 0:0:0:0:0:ffff:fb15:fbd
251.21.15.190 0:0:0:0:0:ffff:fb15:fbe
251.21.15.191 0:0:0:0:0:ffff:fb15:fbf
251.21.15.192 0:0:0:0:0:ffff:fb15:fc0
251.21.15.193 0:0:0:0:0:ffff:fb15:fc1
251.21.15.194 0:0:0:0:0:ffff:fb15:fc2
251.21.15.195 0:0:0:0:0:ffff:fb15:fc3
251.21.15.196 0:0:0:0:0:ffff:fb15:fc4
251.21.15.197 0:0:0:0:0:ffff:fb15:fc5
251.21.15.198 0:0:0:0:0:ffff:fb15:fc6
251.21.15.199 0:0:0:0:0:ffff:fb15:fc7
251.21.15.200 0:0:0:0:0:ffff:fb15:fc8
251.21.15.201 0:0:0:0:0:ffff:fb15:fc9
251.21.15.202 0:0:0:0:0:ffff:fb15:fca
251.21.15.203 0:0:0:0:0:ffff:fb15:fcb
251.21.15.204 0:0:0:0:0:ffff:fb15:fcc
251.21.15.205 0:0:0:0:0:ffff:fb15:fcd
251.21.15.206 0:0:0:0:0:ffff:fb15:fce
251.21.15.207 0:0:0:0:0:ffff:fb15:fcf
251.21.15.208 0:0:0:0:0:ffff:fb15:fd0
251.21.15.209 0:0:0:0:0:ffff:fb15:fd1
251.21.15.210 0:0:0:0:0:ffff:fb15:fd2
251.21.15.211 0:0:0:0:0:ffff:fb15:fd3
251.21.15.212 0:0:0:0:0:ffff:fb15:fd4
251.21.15.213 0:0:0:0:0:ffff:fb15:fd5
251.21.15.214 0:0:0:0:0:ffff:fb15:fd6
251.21.15.215 0:0:0:0:0:ffff:fb15:fd7
251.21.15.216 0:0:0:0:0:ffff:fb15:fd8
251.21.15.217 0:0:0:0:0:ffff:fb15:fd9
251.21.15.218 0:0:0:0:0:ffff:fb15:fda
251.21.15.219 0:0:0:0:0:ffff:fb15:fdb
251.21.15.220 0:0:0:0:0:ffff:fb15:fdc
251.21.15.221 0:0:0:0:0:ffff:fb15:fdd
251.21.15.222 0:0:0:0:0:ffff:fb15:fde
251.21.15.223 0:0:0:0:0:ffff:fb15:fdf
251.21.15.224 0:0:0:0:0:ffff:fb15:fe0
251.21.15.225 0:0:0:0:0:ffff:fb15:fe1
251.21.15.226 0:0:0:0:0:ffff:fb15:fe2
251.21.15.227 0:0:0:0:0:ffff:fb15:fe3
251.21.15.228 0:0:0:0:0:ffff:fb15:fe4
251.21.15.229 0:0:0:0:0:ffff:fb15:fe5
251.21.15.230 0:0:0:0:0:ffff:fb15:fe6
251.21.15.231 0:0:0:0:0:ffff:fb15:fe7
251.21.15.232 0:0:0:0:0:ffff:fb15:fe8
251.21.15.233 0:0:0:0:0:ffff:fb15:fe9
251.21.15.234 0:0:0:0:0:ffff:fb15:fea
251.21.15.235 0:0:0:0:0:ffff:fb15:feb
251.21.15.236 0:0:0:0:0:ffff:fb15:fec
251.21.15.237 0:0:0:0:0:ffff:fb15:fed
251.21.15.238 0:0:0:0:0:ffff:fb15:fee
251.21.15.239 0:0:0:0:0:ffff:fb15:fef
251.21.15.240 0:0:0:0:0:ffff:fb15:ff0
251.21.15.241 0:0:0:0:0:ffff:fb15:ff1
251.21.15.242 0:0:0:0:0:ffff:fb15:ff2
251.21.15.243 0:0:0:0:0:ffff:fb15:ff3
251.21.15.244 0:0:0:0:0:ffff:fb15:ff4
251.21.15.245 0:0:0:0:0:ffff:fb15:ff5
251.21.15.246 0:0:0:0:0:ffff:fb15:ff6
251.21.15.247 0:0:0:0:0:ffff:fb15:ff7
251.21.15.248 0:0:0:0:0:ffff:fb15:ff8
251.21.15.249 0:0:0:0:0:ffff:fb15:ff9
251.21.15.250 0:0:0:0:0:ffff:fb15:ffa
251.21.15.251 0:0:0:0:0:ffff:fb15:ffb
251.21.15.252 0:0:0:0:0:ffff:fb15:ffc
251.21.15.253 0:0:0:0:0:ffff:fb15:ffd
251.21.15.254 0:0:0:0:0:ffff:fb15:ffe
251.21.15.255 0:0:0:0:0:ffff:fb15:fff


How we got IPv4 subnet masks?

An IPv4 subnet mask consists of 32 bits; it is a sequence of ones (1) followed by a block of zeros (0). The ones indicate bits in the address used for the network prefix and the trailing block of zeros designates that part as being the host identifier.