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
128.21.203.1 0:0:0:0:0:ffff:8015:cb01
128.21.203.2 0:0:0:0:0:ffff:8015:cb02
128.21.203.3 0:0:0:0:0:ffff:8015:cb03
128.21.203.4 0:0:0:0:0:ffff:8015:cb04
128.21.203.5 0:0:0:0:0:ffff:8015:cb05
128.21.203.6 0:0:0:0:0:ffff:8015:cb06
128.21.203.7 0:0:0:0:0:ffff:8015:cb07
128.21.203.8 0:0:0:0:0:ffff:8015:cb08
128.21.203.9 0:0:0:0:0:ffff:8015:cb09
128.21.203.10 0:0:0:0:0:ffff:8015:cb0a
128.21.203.11 0:0:0:0:0:ffff:8015:cb0b
128.21.203.12 0:0:0:0:0:ffff:8015:cb0c
128.21.203.13 0:0:0:0:0:ffff:8015:cb0d
128.21.203.14 0:0:0:0:0:ffff:8015:cb0e
128.21.203.15 0:0:0:0:0:ffff:8015:cb0f
128.21.203.16 0:0:0:0:0:ffff:8015:cb10
128.21.203.17 0:0:0:0:0:ffff:8015:cb11
128.21.203.18 0:0:0:0:0:ffff:8015:cb12
128.21.203.19 0:0:0:0:0:ffff:8015:cb13
128.21.203.20 0:0:0:0:0:ffff:8015:cb14
128.21.203.21 0:0:0:0:0:ffff:8015:cb15
128.21.203.22 0:0:0:0:0:ffff:8015:cb16
128.21.203.23 0:0:0:0:0:ffff:8015:cb17
128.21.203.24 0:0:0:0:0:ffff:8015:cb18
128.21.203.25 0:0:0:0:0:ffff:8015:cb19
128.21.203.26 0:0:0:0:0:ffff:8015:cb1a
128.21.203.27 0:0:0:0:0:ffff:8015:cb1b
128.21.203.28 0:0:0:0:0:ffff:8015:cb1c
128.21.203.29 0:0:0:0:0:ffff:8015:cb1d
128.21.203.30 0:0:0:0:0:ffff:8015:cb1e
128.21.203.31 0:0:0:0:0:ffff:8015:cb1f
128.21.203.32 0:0:0:0:0:ffff:8015:cb20
128.21.203.33 0:0:0:0:0:ffff:8015:cb21
128.21.203.34 0:0:0:0:0:ffff:8015:cb22
128.21.203.35 0:0:0:0:0:ffff:8015:cb23
128.21.203.36 0:0:0:0:0:ffff:8015:cb24
128.21.203.37 0:0:0:0:0:ffff:8015:cb25
128.21.203.38 0:0:0:0:0:ffff:8015:cb26
128.21.203.39 0:0:0:0:0:ffff:8015:cb27
128.21.203.40 0:0:0:0:0:ffff:8015:cb28
128.21.203.41 0:0:0:0:0:ffff:8015:cb29
128.21.203.42 0:0:0:0:0:ffff:8015:cb2a
128.21.203.43 0:0:0:0:0:ffff:8015:cb2b
128.21.203.44 0:0:0:0:0:ffff:8015:cb2c
128.21.203.45 0:0:0:0:0:ffff:8015:cb2d
128.21.203.46 0:0:0:0:0:ffff:8015:cb2e
128.21.203.47 0:0:0:0:0:ffff:8015:cb2f
128.21.203.48 0:0:0:0:0:ffff:8015:cb30
128.21.203.49 0:0:0:0:0:ffff:8015:cb31
128.21.203.50 0:0:0:0:0:ffff:8015:cb32
128.21.203.51 0:0:0:0:0:ffff:8015:cb33
128.21.203.52 0:0:0:0:0:ffff:8015:cb34
128.21.203.53 0:0:0:0:0:ffff:8015:cb35
128.21.203.54 0:0:0:0:0:ffff:8015:cb36
128.21.203.55 0:0:0:0:0:ffff:8015:cb37
128.21.203.56 0:0:0:0:0:ffff:8015:cb38
128.21.203.57 0:0:0:0:0:ffff:8015:cb39
128.21.203.58 0:0:0:0:0:ffff:8015:cb3a
128.21.203.59 0:0:0:0:0:ffff:8015:cb3b
128.21.203.60 0:0:0:0:0:ffff:8015:cb3c


128.21.203.61 0:0:0:0:0:ffff:8015:cb3d
128.21.203.62 0:0:0:0:0:ffff:8015:cb3e
128.21.203.63 0:0:0:0:0:ffff:8015:cb3f
128.21.203.64 0:0:0:0:0:ffff:8015:cb40
128.21.203.65 0:0:0:0:0:ffff:8015:cb41
128.21.203.66 0:0:0:0:0:ffff:8015:cb42
128.21.203.67 0:0:0:0:0:ffff:8015:cb43
128.21.203.68 0:0:0:0:0:ffff:8015:cb44
128.21.203.69 0:0:0:0:0:ffff:8015:cb45
128.21.203.70 0:0:0:0:0:ffff:8015:cb46
128.21.203.71 0:0:0:0:0:ffff:8015:cb47
128.21.203.72 0:0:0:0:0:ffff:8015:cb48
128.21.203.73 0:0:0:0:0:ffff:8015:cb49
128.21.203.74 0:0:0:0:0:ffff:8015:cb4a
128.21.203.75 0:0:0:0:0:ffff:8015:cb4b
128.21.203.76 0:0:0:0:0:ffff:8015:cb4c
128.21.203.77 0:0:0:0:0:ffff:8015:cb4d
128.21.203.78 0:0:0:0:0:ffff:8015:cb4e
128.21.203.79 0:0:0:0:0:ffff:8015:cb4f
128.21.203.80 0:0:0:0:0:ffff:8015:cb50
128.21.203.81 0:0:0:0:0:ffff:8015:cb51
128.21.203.82 0:0:0:0:0:ffff:8015:cb52
128.21.203.83 0:0:0:0:0:ffff:8015:cb53
128.21.203.84 0:0:0:0:0:ffff:8015:cb54
128.21.203.85 0:0:0:0:0:ffff:8015:cb55
128.21.203.86 0:0:0:0:0:ffff:8015:cb56
128.21.203.87 0:0:0:0:0:ffff:8015:cb57
128.21.203.88 0:0:0:0:0:ffff:8015:cb58
128.21.203.89 0:0:0:0:0:ffff:8015:cb59
128.21.203.90 0:0:0:0:0:ffff:8015:cb5a
128.21.203.91 0:0:0:0:0:ffff:8015:cb5b
128.21.203.92 0:0:0:0:0:ffff:8015:cb5c
128.21.203.93 0:0:0:0:0:ffff:8015:cb5d
128.21.203.94 0:0:0:0:0:ffff:8015:cb5e
128.21.203.95 0:0:0:0:0:ffff:8015:cb5f
128.21.203.96 0:0:0:0:0:ffff:8015:cb60
128.21.203.97 0:0:0:0:0:ffff:8015:cb61
128.21.203.98 0:0:0:0:0:ffff:8015:cb62
128.21.203.99 0:0:0:0:0:ffff:8015:cb63
128.21.203.100 0:0:0:0:0:ffff:8015:cb64
128.21.203.101 0:0:0:0:0:ffff:8015:cb65
128.21.203.102 0:0:0:0:0:ffff:8015:cb66
128.21.203.103 0:0:0:0:0:ffff:8015:cb67
128.21.203.104 0:0:0:0:0:ffff:8015:cb68
128.21.203.105 0:0:0:0:0:ffff:8015:cb69
128.21.203.106 0:0:0:0:0:ffff:8015:cb6a
128.21.203.107 0:0:0:0:0:ffff:8015:cb6b
128.21.203.108 0:0:0:0:0:ffff:8015:cb6c
128.21.203.109 0:0:0:0:0:ffff:8015:cb6d
128.21.203.110 0:0:0:0:0:ffff:8015:cb6e
128.21.203.111 0:0:0:0:0:ffff:8015:cb6f
128.21.203.112 0:0:0:0:0:ffff:8015:cb70
128.21.203.113 0:0:0:0:0:ffff:8015:cb71
128.21.203.114 0:0:0:0:0:ffff:8015:cb72
128.21.203.115 0:0:0:0:0:ffff:8015:cb73
128.21.203.116 0:0:0:0:0:ffff:8015:cb74
128.21.203.117 0:0:0:0:0:ffff:8015:cb75
128.21.203.118 0:0:0:0:0:ffff:8015:cb76
128.21.203.119 0:0:0:0:0:ffff:8015:cb77
128.21.203.120 0:0:0:0:0:ffff:8015:cb78


128.21.203.121 0:0:0:0:0:ffff:8015:cb79
128.21.203.122 0:0:0:0:0:ffff:8015:cb7a
128.21.203.123 0:0:0:0:0:ffff:8015:cb7b
128.21.203.124 0:0:0:0:0:ffff:8015:cb7c
128.21.203.125 0:0:0:0:0:ffff:8015:cb7d
128.21.203.126 0:0:0:0:0:ffff:8015:cb7e
128.21.203.127 0:0:0:0:0:ffff:8015:cb7f
128.21.203.128 0:0:0:0:0:ffff:8015:cb80
128.21.203.129 0:0:0:0:0:ffff:8015:cb81
128.21.203.130 0:0:0:0:0:ffff:8015:cb82
128.21.203.131 0:0:0:0:0:ffff:8015:cb83
128.21.203.132 0:0:0:0:0:ffff:8015:cb84
128.21.203.133 0:0:0:0:0:ffff:8015:cb85
128.21.203.134 0:0:0:0:0:ffff:8015:cb86
128.21.203.135 0:0:0:0:0:ffff:8015:cb87
128.21.203.136 0:0:0:0:0:ffff:8015:cb88
128.21.203.137 0:0:0:0:0:ffff:8015:cb89
128.21.203.138 0:0:0:0:0:ffff:8015:cb8a
128.21.203.139 0:0:0:0:0:ffff:8015:cb8b
128.21.203.140 0:0:0:0:0:ffff:8015:cb8c
128.21.203.141 0:0:0:0:0:ffff:8015:cb8d
128.21.203.142 0:0:0:0:0:ffff:8015:cb8e
128.21.203.143 0:0:0:0:0:ffff:8015:cb8f
128.21.203.144 0:0:0:0:0:ffff:8015:cb90
128.21.203.145 0:0:0:0:0:ffff:8015:cb91
128.21.203.146 0:0:0:0:0:ffff:8015:cb92
128.21.203.147 0:0:0:0:0:ffff:8015:cb93
128.21.203.148 0:0:0:0:0:ffff:8015:cb94
128.21.203.149 0:0:0:0:0:ffff:8015:cb95
128.21.203.150 0:0:0:0:0:ffff:8015:cb96
128.21.203.151 0:0:0:0:0:ffff:8015:cb97
128.21.203.152 0:0:0:0:0:ffff:8015:cb98
128.21.203.153 0:0:0:0:0:ffff:8015:cb99
128.21.203.154 0:0:0:0:0:ffff:8015:cb9a
128.21.203.155 0:0:0:0:0:ffff:8015:cb9b
128.21.203.156 0:0:0:0:0:ffff:8015:cb9c
128.21.203.157 0:0:0:0:0:ffff:8015:cb9d
128.21.203.158 0:0:0:0:0:ffff:8015:cb9e
128.21.203.159 0:0:0:0:0:ffff:8015:cb9f
128.21.203.160 0:0:0:0:0:ffff:8015:cba0
128.21.203.161 0:0:0:0:0:ffff:8015:cba1
128.21.203.162 0:0:0:0:0:ffff:8015:cba2
128.21.203.163 0:0:0:0:0:ffff:8015:cba3
128.21.203.164 0:0:0:0:0:ffff:8015:cba4
128.21.203.165 0:0:0:0:0:ffff:8015:cba5
128.21.203.166 0:0:0:0:0:ffff:8015:cba6
128.21.203.167 0:0:0:0:0:ffff:8015:cba7
128.21.203.168 0:0:0:0:0:ffff:8015:cba8
128.21.203.169 0:0:0:0:0:ffff:8015:cba9
128.21.203.170 0:0:0:0:0:ffff:8015:cbaa
128.21.203.171 0:0:0:0:0:ffff:8015:cbab
128.21.203.172 0:0:0:0:0:ffff:8015:cbac
128.21.203.173 0:0:0:0:0:ffff:8015:cbad
128.21.203.174 0:0:0:0:0:ffff:8015:cbae
128.21.203.175 0:0:0:0:0:ffff:8015:cbaf
128.21.203.176 0:0:0:0:0:ffff:8015:cbb0
128.21.203.177 0:0:0:0:0:ffff:8015:cbb1
128.21.203.178 0:0:0:0:0:ffff:8015:cbb2
128.21.203.179 0:0:0:0:0:ffff:8015:cbb3
128.21.203.180 0:0:0:0:0:ffff:8015:cbb4


128.21.203.181 0:0:0:0:0:ffff:8015:cbb5
128.21.203.182 0:0:0:0:0:ffff:8015:cbb6
128.21.203.183 0:0:0:0:0:ffff:8015:cbb7
128.21.203.184 0:0:0:0:0:ffff:8015:cbb8
128.21.203.185 0:0:0:0:0:ffff:8015:cbb9
128.21.203.186 0:0:0:0:0:ffff:8015:cbba
128.21.203.187 0:0:0:0:0:ffff:8015:cbbb
128.21.203.188 0:0:0:0:0:ffff:8015:cbbc
128.21.203.189 0:0:0:0:0:ffff:8015:cbbd
128.21.203.190 0:0:0:0:0:ffff:8015:cbbe
128.21.203.191 0:0:0:0:0:ffff:8015:cbbf
128.21.203.192 0:0:0:0:0:ffff:8015:cbc0
128.21.203.193 0:0:0:0:0:ffff:8015:cbc1
128.21.203.194 0:0:0:0:0:ffff:8015:cbc2
128.21.203.195 0:0:0:0:0:ffff:8015:cbc3
128.21.203.196 0:0:0:0:0:ffff:8015:cbc4
128.21.203.197 0:0:0:0:0:ffff:8015:cbc5
128.21.203.198 0:0:0:0:0:ffff:8015:cbc6
128.21.203.199 0:0:0:0:0:ffff:8015:cbc7
128.21.203.200 0:0:0:0:0:ffff:8015:cbc8
128.21.203.201 0:0:0:0:0:ffff:8015:cbc9
128.21.203.202 0:0:0:0:0:ffff:8015:cbca
128.21.203.203 0:0:0:0:0:ffff:8015:cbcb
128.21.203.204 0:0:0:0:0:ffff:8015:cbcc
128.21.203.205 0:0:0:0:0:ffff:8015:cbcd
128.21.203.206 0:0:0:0:0:ffff:8015:cbce
128.21.203.207 0:0:0:0:0:ffff:8015:cbcf
128.21.203.208 0:0:0:0:0:ffff:8015:cbd0
128.21.203.209 0:0:0:0:0:ffff:8015:cbd1
128.21.203.210 0:0:0:0:0:ffff:8015:cbd2
128.21.203.211 0:0:0:0:0:ffff:8015:cbd3
128.21.203.212 0:0:0:0:0:ffff:8015:cbd4
128.21.203.213 0:0:0:0:0:ffff:8015:cbd5
128.21.203.214 0:0:0:0:0:ffff:8015:cbd6
128.21.203.215 0:0:0:0:0:ffff:8015:cbd7
128.21.203.216 0:0:0:0:0:ffff:8015:cbd8
128.21.203.217 0:0:0:0:0:ffff:8015:cbd9
128.21.203.218 0:0:0:0:0:ffff:8015:cbda
128.21.203.219 0:0:0:0:0:ffff:8015:cbdb
128.21.203.220 0:0:0:0:0:ffff:8015:cbdc
128.21.203.221 0:0:0:0:0:ffff:8015:cbdd
128.21.203.222 0:0:0:0:0:ffff:8015:cbde
128.21.203.223 0:0:0:0:0:ffff:8015:cbdf
128.21.203.224 0:0:0:0:0:ffff:8015:cbe0
128.21.203.225 0:0:0:0:0:ffff:8015:cbe1
128.21.203.226 0:0:0:0:0:ffff:8015:cbe2
128.21.203.227 0:0:0:0:0:ffff:8015:cbe3
128.21.203.228 0:0:0:0:0:ffff:8015:cbe4
128.21.203.229 0:0:0:0:0:ffff:8015:cbe5
128.21.203.230 0:0:0:0:0:ffff:8015:cbe6
128.21.203.231 0:0:0:0:0:ffff:8015:cbe7
128.21.203.232 0:0:0:0:0:ffff:8015:cbe8
128.21.203.233 0:0:0:0:0:ffff:8015:cbe9
128.21.203.234 0:0:0:0:0:ffff:8015:cbea
128.21.203.235 0:0:0:0:0:ffff:8015:cbeb
128.21.203.236 0:0:0:0:0:ffff:8015:cbec
128.21.203.237 0:0:0:0:0:ffff:8015:cbed
128.21.203.238 0:0:0:0:0:ffff:8015:cbee
128.21.203.239 0:0:0:0:0:ffff:8015:cbef
128.21.203.240 0:0:0:0:0:ffff:8015:cbf0
128.21.203.241 0:0:0:0:0:ffff:8015:cbf1
128.21.203.242 0:0:0:0:0:ffff:8015:cbf2
128.21.203.243 0:0:0:0:0:ffff:8015:cbf3
128.21.203.244 0:0:0:0:0:ffff:8015:cbf4
128.21.203.245 0:0:0:0:0:ffff:8015:cbf5
128.21.203.246 0:0:0:0:0:ffff:8015:cbf6
128.21.203.247 0:0:0:0:0:ffff:8015:cbf7
128.21.203.248 0:0:0:0:0:ffff:8015:cbf8
128.21.203.249 0:0:0:0:0:ffff:8015:cbf9
128.21.203.250 0:0:0:0:0:ffff:8015:cbfa
128.21.203.251 0:0:0:0:0:ffff:8015:cbfb
128.21.203.252 0:0:0:0:0:ffff:8015:cbfc
128.21.203.253 0:0:0:0:0:ffff:8015:cbfd
128.21.203.254 0:0:0:0:0:ffff:8015:cbfe
128.21.203.255 0:0:0:0:0:ffff:8015:cbff


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.