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
187.21.1.1 0:0:0:0:0:ffff:bb15:101
187.21.1.2 0:0:0:0:0:ffff:bb15:102
187.21.1.3 0:0:0:0:0:ffff:bb15:103
187.21.1.4 0:0:0:0:0:ffff:bb15:104
187.21.1.5 0:0:0:0:0:ffff:bb15:105
187.21.1.6 0:0:0:0:0:ffff:bb15:106
187.21.1.7 0:0:0:0:0:ffff:bb15:107
187.21.1.8 0:0:0:0:0:ffff:bb15:108
187.21.1.9 0:0:0:0:0:ffff:bb15:109
187.21.1.10 0:0:0:0:0:ffff:bb15:10a
187.21.1.11 0:0:0:0:0:ffff:bb15:10b
187.21.1.12 0:0:0:0:0:ffff:bb15:10c
187.21.1.13 0:0:0:0:0:ffff:bb15:10d
187.21.1.14 0:0:0:0:0:ffff:bb15:10e
187.21.1.15 0:0:0:0:0:ffff:bb15:10f
187.21.1.16 0:0:0:0:0:ffff:bb15:110
187.21.1.17 0:0:0:0:0:ffff:bb15:111
187.21.1.18 0:0:0:0:0:ffff:bb15:112
187.21.1.19 0:0:0:0:0:ffff:bb15:113
187.21.1.20 0:0:0:0:0:ffff:bb15:114
187.21.1.21 0:0:0:0:0:ffff:bb15:115
187.21.1.22 0:0:0:0:0:ffff:bb15:116
187.21.1.23 0:0:0:0:0:ffff:bb15:117
187.21.1.24 0:0:0:0:0:ffff:bb15:118
187.21.1.25 0:0:0:0:0:ffff:bb15:119
187.21.1.26 0:0:0:0:0:ffff:bb15:11a
187.21.1.27 0:0:0:0:0:ffff:bb15:11b
187.21.1.28 0:0:0:0:0:ffff:bb15:11c
187.21.1.29 0:0:0:0:0:ffff:bb15:11d
187.21.1.30 0:0:0:0:0:ffff:bb15:11e
187.21.1.31 0:0:0:0:0:ffff:bb15:11f
187.21.1.32 0:0:0:0:0:ffff:bb15:120
187.21.1.33 0:0:0:0:0:ffff:bb15:121
187.21.1.34 0:0:0:0:0:ffff:bb15:122
187.21.1.35 0:0:0:0:0:ffff:bb15:123
187.21.1.36 0:0:0:0:0:ffff:bb15:124
187.21.1.37 0:0:0:0:0:ffff:bb15:125
187.21.1.38 0:0:0:0:0:ffff:bb15:126
187.21.1.39 0:0:0:0:0:ffff:bb15:127
187.21.1.40 0:0:0:0:0:ffff:bb15:128
187.21.1.41 0:0:0:0:0:ffff:bb15:129
187.21.1.42 0:0:0:0:0:ffff:bb15:12a
187.21.1.43 0:0:0:0:0:ffff:bb15:12b
187.21.1.44 0:0:0:0:0:ffff:bb15:12c
187.21.1.45 0:0:0:0:0:ffff:bb15:12d
187.21.1.46 0:0:0:0:0:ffff:bb15:12e
187.21.1.47 0:0:0:0:0:ffff:bb15:12f
187.21.1.48 0:0:0:0:0:ffff:bb15:130
187.21.1.49 0:0:0:0:0:ffff:bb15:131
187.21.1.50 0:0:0:0:0:ffff:bb15:132
187.21.1.51 0:0:0:0:0:ffff:bb15:133
187.21.1.52 0:0:0:0:0:ffff:bb15:134
187.21.1.53 0:0:0:0:0:ffff:bb15:135
187.21.1.54 0:0:0:0:0:ffff:bb15:136
187.21.1.55 0:0:0:0:0:ffff:bb15:137
187.21.1.56 0:0:0:0:0:ffff:bb15:138
187.21.1.57 0:0:0:0:0:ffff:bb15:139
187.21.1.58 0:0:0:0:0:ffff:bb15:13a
187.21.1.59 0:0:0:0:0:ffff:bb15:13b
187.21.1.60 0:0:0:0:0:ffff:bb15:13c


187.21.1.61 0:0:0:0:0:ffff:bb15:13d
187.21.1.62 0:0:0:0:0:ffff:bb15:13e
187.21.1.63 0:0:0:0:0:ffff:bb15:13f
187.21.1.64 0:0:0:0:0:ffff:bb15:140
187.21.1.65 0:0:0:0:0:ffff:bb15:141
187.21.1.66 0:0:0:0:0:ffff:bb15:142
187.21.1.67 0:0:0:0:0:ffff:bb15:143
187.21.1.68 0:0:0:0:0:ffff:bb15:144
187.21.1.69 0:0:0:0:0:ffff:bb15:145
187.21.1.70 0:0:0:0:0:ffff:bb15:146
187.21.1.71 0:0:0:0:0:ffff:bb15:147
187.21.1.72 0:0:0:0:0:ffff:bb15:148
187.21.1.73 0:0:0:0:0:ffff:bb15:149
187.21.1.74 0:0:0:0:0:ffff:bb15:14a
187.21.1.75 0:0:0:0:0:ffff:bb15:14b
187.21.1.76 0:0:0:0:0:ffff:bb15:14c
187.21.1.77 0:0:0:0:0:ffff:bb15:14d
187.21.1.78 0:0:0:0:0:ffff:bb15:14e
187.21.1.79 0:0:0:0:0:ffff:bb15:14f
187.21.1.80 0:0:0:0:0:ffff:bb15:150
187.21.1.81 0:0:0:0:0:ffff:bb15:151
187.21.1.82 0:0:0:0:0:ffff:bb15:152
187.21.1.83 0:0:0:0:0:ffff:bb15:153
187.21.1.84 0:0:0:0:0:ffff:bb15:154
187.21.1.85 0:0:0:0:0:ffff:bb15:155
187.21.1.86 0:0:0:0:0:ffff:bb15:156
187.21.1.87 0:0:0:0:0:ffff:bb15:157
187.21.1.88 0:0:0:0:0:ffff:bb15:158
187.21.1.89 0:0:0:0:0:ffff:bb15:159
187.21.1.90 0:0:0:0:0:ffff:bb15:15a
187.21.1.91 0:0:0:0:0:ffff:bb15:15b
187.21.1.92 0:0:0:0:0:ffff:bb15:15c
187.21.1.93 0:0:0:0:0:ffff:bb15:15d
187.21.1.94 0:0:0:0:0:ffff:bb15:15e
187.21.1.95 0:0:0:0:0:ffff:bb15:15f
187.21.1.96 0:0:0:0:0:ffff:bb15:160
187.21.1.97 0:0:0:0:0:ffff:bb15:161
187.21.1.98 0:0:0:0:0:ffff:bb15:162
187.21.1.99 0:0:0:0:0:ffff:bb15:163
187.21.1.100 0:0:0:0:0:ffff:bb15:164
187.21.1.101 0:0:0:0:0:ffff:bb15:165
187.21.1.102 0:0:0:0:0:ffff:bb15:166
187.21.1.103 0:0:0:0:0:ffff:bb15:167
187.21.1.104 0:0:0:0:0:ffff:bb15:168
187.21.1.105 0:0:0:0:0:ffff:bb15:169
187.21.1.106 0:0:0:0:0:ffff:bb15:16a
187.21.1.107 0:0:0:0:0:ffff:bb15:16b
187.21.1.108 0:0:0:0:0:ffff:bb15:16c
187.21.1.109 0:0:0:0:0:ffff:bb15:16d
187.21.1.110 0:0:0:0:0:ffff:bb15:16e
187.21.1.111 0:0:0:0:0:ffff:bb15:16f
187.21.1.112 0:0:0:0:0:ffff:bb15:170
187.21.1.113 0:0:0:0:0:ffff:bb15:171
187.21.1.114 0:0:0:0:0:ffff:bb15:172
187.21.1.115 0:0:0:0:0:ffff:bb15:173
187.21.1.116 0:0:0:0:0:ffff:bb15:174
187.21.1.117 0:0:0:0:0:ffff:bb15:175
187.21.1.118 0:0:0:0:0:ffff:bb15:176
187.21.1.119 0:0:0:0:0:ffff:bb15:177
187.21.1.120 0:0:0:0:0:ffff:bb15:178


187.21.1.121 0:0:0:0:0:ffff:bb15:179
187.21.1.122 0:0:0:0:0:ffff:bb15:17a
187.21.1.123 0:0:0:0:0:ffff:bb15:17b
187.21.1.124 0:0:0:0:0:ffff:bb15:17c
187.21.1.125 0:0:0:0:0:ffff:bb15:17d
187.21.1.126 0:0:0:0:0:ffff:bb15:17e
187.21.1.127 0:0:0:0:0:ffff:bb15:17f
187.21.1.128 0:0:0:0:0:ffff:bb15:180
187.21.1.129 0:0:0:0:0:ffff:bb15:181
187.21.1.130 0:0:0:0:0:ffff:bb15:182
187.21.1.131 0:0:0:0:0:ffff:bb15:183
187.21.1.132 0:0:0:0:0:ffff:bb15:184
187.21.1.133 0:0:0:0:0:ffff:bb15:185
187.21.1.134 0:0:0:0:0:ffff:bb15:186
187.21.1.135 0:0:0:0:0:ffff:bb15:187
187.21.1.136 0:0:0:0:0:ffff:bb15:188
187.21.1.137 0:0:0:0:0:ffff:bb15:189
187.21.1.138 0:0:0:0:0:ffff:bb15:18a
187.21.1.139 0:0:0:0:0:ffff:bb15:18b
187.21.1.140 0:0:0:0:0:ffff:bb15:18c
187.21.1.141 0:0:0:0:0:ffff:bb15:18d
187.21.1.142 0:0:0:0:0:ffff:bb15:18e
187.21.1.143 0:0:0:0:0:ffff:bb15:18f
187.21.1.144 0:0:0:0:0:ffff:bb15:190
187.21.1.145 0:0:0:0:0:ffff:bb15:191
187.21.1.146 0:0:0:0:0:ffff:bb15:192
187.21.1.147 0:0:0:0:0:ffff:bb15:193
187.21.1.148 0:0:0:0:0:ffff:bb15:194
187.21.1.149 0:0:0:0:0:ffff:bb15:195
187.21.1.150 0:0:0:0:0:ffff:bb15:196
187.21.1.151 0:0:0:0:0:ffff:bb15:197
187.21.1.152 0:0:0:0:0:ffff:bb15:198
187.21.1.153 0:0:0:0:0:ffff:bb15:199
187.21.1.154 0:0:0:0:0:ffff:bb15:19a
187.21.1.155 0:0:0:0:0:ffff:bb15:19b
187.21.1.156 0:0:0:0:0:ffff:bb15:19c
187.21.1.157 0:0:0:0:0:ffff:bb15:19d
187.21.1.158 0:0:0:0:0:ffff:bb15:19e
187.21.1.159 0:0:0:0:0:ffff:bb15:19f
187.21.1.160 0:0:0:0:0:ffff:bb15:1a0
187.21.1.161 0:0:0:0:0:ffff:bb15:1a1
187.21.1.162 0:0:0:0:0:ffff:bb15:1a2
187.21.1.163 0:0:0:0:0:ffff:bb15:1a3
187.21.1.164 0:0:0:0:0:ffff:bb15:1a4
187.21.1.165 0:0:0:0:0:ffff:bb15:1a5
187.21.1.166 0:0:0:0:0:ffff:bb15:1a6
187.21.1.167 0:0:0:0:0:ffff:bb15:1a7
187.21.1.168 0:0:0:0:0:ffff:bb15:1a8
187.21.1.169 0:0:0:0:0:ffff:bb15:1a9
187.21.1.170 0:0:0:0:0:ffff:bb15:1aa
187.21.1.171 0:0:0:0:0:ffff:bb15:1ab
187.21.1.172 0:0:0:0:0:ffff:bb15:1ac
187.21.1.173 0:0:0:0:0:ffff:bb15:1ad
187.21.1.174 0:0:0:0:0:ffff:bb15:1ae
187.21.1.175 0:0:0:0:0:ffff:bb15:1af
187.21.1.176 0:0:0:0:0:ffff:bb15:1b0
187.21.1.177 0:0:0:0:0:ffff:bb15:1b1
187.21.1.178 0:0:0:0:0:ffff:bb15:1b2
187.21.1.179 0:0:0:0:0:ffff:bb15:1b3
187.21.1.180 0:0:0:0:0:ffff:bb15:1b4


187.21.1.181 0:0:0:0:0:ffff:bb15:1b5
187.21.1.182 0:0:0:0:0:ffff:bb15:1b6
187.21.1.183 0:0:0:0:0:ffff:bb15:1b7
187.21.1.184 0:0:0:0:0:ffff:bb15:1b8
187.21.1.185 0:0:0:0:0:ffff:bb15:1b9
187.21.1.186 0:0:0:0:0:ffff:bb15:1ba
187.21.1.187 0:0:0:0:0:ffff:bb15:1bb
187.21.1.188 0:0:0:0:0:ffff:bb15:1bc
187.21.1.189 0:0:0:0:0:ffff:bb15:1bd
187.21.1.190 0:0:0:0:0:ffff:bb15:1be
187.21.1.191 0:0:0:0:0:ffff:bb15:1bf
187.21.1.192 0:0:0:0:0:ffff:bb15:1c0
187.21.1.193 0:0:0:0:0:ffff:bb15:1c1
187.21.1.194 0:0:0:0:0:ffff:bb15:1c2
187.21.1.195 0:0:0:0:0:ffff:bb15:1c3
187.21.1.196 0:0:0:0:0:ffff:bb15:1c4
187.21.1.197 0:0:0:0:0:ffff:bb15:1c5
187.21.1.198 0:0:0:0:0:ffff:bb15:1c6
187.21.1.199 0:0:0:0:0:ffff:bb15:1c7
187.21.1.200 0:0:0:0:0:ffff:bb15:1c8
187.21.1.201 0:0:0:0:0:ffff:bb15:1c9
187.21.1.202 0:0:0:0:0:ffff:bb15:1ca
187.21.1.203 0:0:0:0:0:ffff:bb15:1cb
187.21.1.204 0:0:0:0:0:ffff:bb15:1cc
187.21.1.205 0:0:0:0:0:ffff:bb15:1cd
187.21.1.206 0:0:0:0:0:ffff:bb15:1ce
187.21.1.207 0:0:0:0:0:ffff:bb15:1cf
187.21.1.208 0:0:0:0:0:ffff:bb15:1d0
187.21.1.209 0:0:0:0:0:ffff:bb15:1d1
187.21.1.210 0:0:0:0:0:ffff:bb15:1d2
187.21.1.211 0:0:0:0:0:ffff:bb15:1d3
187.21.1.212 0:0:0:0:0:ffff:bb15:1d4
187.21.1.213 0:0:0:0:0:ffff:bb15:1d5
187.21.1.214 0:0:0:0:0:ffff:bb15:1d6
187.21.1.215 0:0:0:0:0:ffff:bb15:1d7
187.21.1.216 0:0:0:0:0:ffff:bb15:1d8
187.21.1.217 0:0:0:0:0:ffff:bb15:1d9
187.21.1.218 0:0:0:0:0:ffff:bb15:1da
187.21.1.219 0:0:0:0:0:ffff:bb15:1db
187.21.1.220 0:0:0:0:0:ffff:bb15:1dc
187.21.1.221 0:0:0:0:0:ffff:bb15:1dd
187.21.1.222 0:0:0:0:0:ffff:bb15:1de
187.21.1.223 0:0:0:0:0:ffff:bb15:1df
187.21.1.224 0:0:0:0:0:ffff:bb15:1e0
187.21.1.225 0:0:0:0:0:ffff:bb15:1e1
187.21.1.226 0:0:0:0:0:ffff:bb15:1e2
187.21.1.227 0:0:0:0:0:ffff:bb15:1e3
187.21.1.228 0:0:0:0:0:ffff:bb15:1e4
187.21.1.229 0:0:0:0:0:ffff:bb15:1e5
187.21.1.230 0:0:0:0:0:ffff:bb15:1e6
187.21.1.231 0:0:0:0:0:ffff:bb15:1e7
187.21.1.232 0:0:0:0:0:ffff:bb15:1e8
187.21.1.233 0:0:0:0:0:ffff:bb15:1e9
187.21.1.234 0:0:0:0:0:ffff:bb15:1ea
187.21.1.235 0:0:0:0:0:ffff:bb15:1eb
187.21.1.236 0:0:0:0:0:ffff:bb15:1ec
187.21.1.237 0:0:0:0:0:ffff:bb15:1ed
187.21.1.238 0:0:0:0:0:ffff:bb15:1ee
187.21.1.239 0:0:0:0:0:ffff:bb15:1ef
187.21.1.240 0:0:0:0:0:ffff:bb15:1f0
187.21.1.241 0:0:0:0:0:ffff:bb15:1f1
187.21.1.242 0:0:0:0:0:ffff:bb15:1f2
187.21.1.243 0:0:0:0:0:ffff:bb15:1f3
187.21.1.244 0:0:0:0:0:ffff:bb15:1f4
187.21.1.245 0:0:0:0:0:ffff:bb15:1f5
187.21.1.246 0:0:0:0:0:ffff:bb15:1f6
187.21.1.247 0:0:0:0:0:ffff:bb15:1f7
187.21.1.248 0:0:0:0:0:ffff:bb15:1f8
187.21.1.249 0:0:0:0:0:ffff:bb15:1f9
187.21.1.250 0:0:0:0:0:ffff:bb15:1fa
187.21.1.251 0:0:0:0:0:ffff:bb15:1fb
187.21.1.252 0:0:0:0:0:ffff:bb15:1fc
187.21.1.253 0:0:0:0:0:ffff:bb15:1fd
187.21.1.254 0:0:0:0:0:ffff:bb15:1fe
187.21.1.255 0:0:0:0:0:ffff:bb15:1ff


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.