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
128.21.205.1 0:0:0:0:0:ffff:8015:cd01
128.21.205.2 0:0:0:0:0:ffff:8015:cd02
128.21.205.3 0:0:0:0:0:ffff:8015:cd03
128.21.205.4 0:0:0:0:0:ffff:8015:cd04
128.21.205.5 0:0:0:0:0:ffff:8015:cd05
128.21.205.6 0:0:0:0:0:ffff:8015:cd06
128.21.205.7 0:0:0:0:0:ffff:8015:cd07
128.21.205.8 0:0:0:0:0:ffff:8015:cd08
128.21.205.9 0:0:0:0:0:ffff:8015:cd09
128.21.205.10 0:0:0:0:0:ffff:8015:cd0a
128.21.205.11 0:0:0:0:0:ffff:8015:cd0b
128.21.205.12 0:0:0:0:0:ffff:8015:cd0c
128.21.205.13 0:0:0:0:0:ffff:8015:cd0d
128.21.205.14 0:0:0:0:0:ffff:8015:cd0e
128.21.205.15 0:0:0:0:0:ffff:8015:cd0f
128.21.205.16 0:0:0:0:0:ffff:8015:cd10
128.21.205.17 0:0:0:0:0:ffff:8015:cd11
128.21.205.18 0:0:0:0:0:ffff:8015:cd12
128.21.205.19 0:0:0:0:0:ffff:8015:cd13
128.21.205.20 0:0:0:0:0:ffff:8015:cd14
128.21.205.21 0:0:0:0:0:ffff:8015:cd15
128.21.205.22 0:0:0:0:0:ffff:8015:cd16
128.21.205.23 0:0:0:0:0:ffff:8015:cd17
128.21.205.24 0:0:0:0:0:ffff:8015:cd18
128.21.205.25 0:0:0:0:0:ffff:8015:cd19
128.21.205.26 0:0:0:0:0:ffff:8015:cd1a
128.21.205.27 0:0:0:0:0:ffff:8015:cd1b
128.21.205.28 0:0:0:0:0:ffff:8015:cd1c
128.21.205.29 0:0:0:0:0:ffff:8015:cd1d
128.21.205.30 0:0:0:0:0:ffff:8015:cd1e
128.21.205.31 0:0:0:0:0:ffff:8015:cd1f
128.21.205.32 0:0:0:0:0:ffff:8015:cd20
128.21.205.33 0:0:0:0:0:ffff:8015:cd21
128.21.205.34 0:0:0:0:0:ffff:8015:cd22
128.21.205.35 0:0:0:0:0:ffff:8015:cd23
128.21.205.36 0:0:0:0:0:ffff:8015:cd24
128.21.205.37 0:0:0:0:0:ffff:8015:cd25
128.21.205.38 0:0:0:0:0:ffff:8015:cd26
128.21.205.39 0:0:0:0:0:ffff:8015:cd27
128.21.205.40 0:0:0:0:0:ffff:8015:cd28
128.21.205.41 0:0:0:0:0:ffff:8015:cd29
128.21.205.42 0:0:0:0:0:ffff:8015:cd2a
128.21.205.43 0:0:0:0:0:ffff:8015:cd2b
128.21.205.44 0:0:0:0:0:ffff:8015:cd2c
128.21.205.45 0:0:0:0:0:ffff:8015:cd2d
128.21.205.46 0:0:0:0:0:ffff:8015:cd2e
128.21.205.47 0:0:0:0:0:ffff:8015:cd2f
128.21.205.48 0:0:0:0:0:ffff:8015:cd30
128.21.205.49 0:0:0:0:0:ffff:8015:cd31
128.21.205.50 0:0:0:0:0:ffff:8015:cd32
128.21.205.51 0:0:0:0:0:ffff:8015:cd33
128.21.205.52 0:0:0:0:0:ffff:8015:cd34
128.21.205.53 0:0:0:0:0:ffff:8015:cd35
128.21.205.54 0:0:0:0:0:ffff:8015:cd36
128.21.205.55 0:0:0:0:0:ffff:8015:cd37
128.21.205.56 0:0:0:0:0:ffff:8015:cd38
128.21.205.57 0:0:0:0:0:ffff:8015:cd39
128.21.205.58 0:0:0:0:0:ffff:8015:cd3a
128.21.205.59 0:0:0:0:0:ffff:8015:cd3b
128.21.205.60 0:0:0:0:0:ffff:8015:cd3c


128.21.205.61 0:0:0:0:0:ffff:8015:cd3d
128.21.205.62 0:0:0:0:0:ffff:8015:cd3e
128.21.205.63 0:0:0:0:0:ffff:8015:cd3f
128.21.205.64 0:0:0:0:0:ffff:8015:cd40
128.21.205.65 0:0:0:0:0:ffff:8015:cd41
128.21.205.66 0:0:0:0:0:ffff:8015:cd42
128.21.205.67 0:0:0:0:0:ffff:8015:cd43
128.21.205.68 0:0:0:0:0:ffff:8015:cd44
128.21.205.69 0:0:0:0:0:ffff:8015:cd45
128.21.205.70 0:0:0:0:0:ffff:8015:cd46
128.21.205.71 0:0:0:0:0:ffff:8015:cd47
128.21.205.72 0:0:0:0:0:ffff:8015:cd48
128.21.205.73 0:0:0:0:0:ffff:8015:cd49
128.21.205.74 0:0:0:0:0:ffff:8015:cd4a
128.21.205.75 0:0:0:0:0:ffff:8015:cd4b
128.21.205.76 0:0:0:0:0:ffff:8015:cd4c
128.21.205.77 0:0:0:0:0:ffff:8015:cd4d
128.21.205.78 0:0:0:0:0:ffff:8015:cd4e
128.21.205.79 0:0:0:0:0:ffff:8015:cd4f
128.21.205.80 0:0:0:0:0:ffff:8015:cd50
128.21.205.81 0:0:0:0:0:ffff:8015:cd51
128.21.205.82 0:0:0:0:0:ffff:8015:cd52
128.21.205.83 0:0:0:0:0:ffff:8015:cd53
128.21.205.84 0:0:0:0:0:ffff:8015:cd54
128.21.205.85 0:0:0:0:0:ffff:8015:cd55
128.21.205.86 0:0:0:0:0:ffff:8015:cd56
128.21.205.87 0:0:0:0:0:ffff:8015:cd57
128.21.205.88 0:0:0:0:0:ffff:8015:cd58
128.21.205.89 0:0:0:0:0:ffff:8015:cd59
128.21.205.90 0:0:0:0:0:ffff:8015:cd5a
128.21.205.91 0:0:0:0:0:ffff:8015:cd5b
128.21.205.92 0:0:0:0:0:ffff:8015:cd5c
128.21.205.93 0:0:0:0:0:ffff:8015:cd5d
128.21.205.94 0:0:0:0:0:ffff:8015:cd5e
128.21.205.95 0:0:0:0:0:ffff:8015:cd5f
128.21.205.96 0:0:0:0:0:ffff:8015:cd60
128.21.205.97 0:0:0:0:0:ffff:8015:cd61
128.21.205.98 0:0:0:0:0:ffff:8015:cd62
128.21.205.99 0:0:0:0:0:ffff:8015:cd63
128.21.205.100 0:0:0:0:0:ffff:8015:cd64
128.21.205.101 0:0:0:0:0:ffff:8015:cd65
128.21.205.102 0:0:0:0:0:ffff:8015:cd66
128.21.205.103 0:0:0:0:0:ffff:8015:cd67
128.21.205.104 0:0:0:0:0:ffff:8015:cd68
128.21.205.105 0:0:0:0:0:ffff:8015:cd69
128.21.205.106 0:0:0:0:0:ffff:8015:cd6a
128.21.205.107 0:0:0:0:0:ffff:8015:cd6b
128.21.205.108 0:0:0:0:0:ffff:8015:cd6c
128.21.205.109 0:0:0:0:0:ffff:8015:cd6d
128.21.205.110 0:0:0:0:0:ffff:8015:cd6e
128.21.205.111 0:0:0:0:0:ffff:8015:cd6f
128.21.205.112 0:0:0:0:0:ffff:8015:cd70
128.21.205.113 0:0:0:0:0:ffff:8015:cd71
128.21.205.114 0:0:0:0:0:ffff:8015:cd72
128.21.205.115 0:0:0:0:0:ffff:8015:cd73
128.21.205.116 0:0:0:0:0:ffff:8015:cd74
128.21.205.117 0:0:0:0:0:ffff:8015:cd75
128.21.205.118 0:0:0:0:0:ffff:8015:cd76
128.21.205.119 0:0:0:0:0:ffff:8015:cd77
128.21.205.120 0:0:0:0:0:ffff:8015:cd78


128.21.205.121 0:0:0:0:0:ffff:8015:cd79
128.21.205.122 0:0:0:0:0:ffff:8015:cd7a
128.21.205.123 0:0:0:0:0:ffff:8015:cd7b
128.21.205.124 0:0:0:0:0:ffff:8015:cd7c
128.21.205.125 0:0:0:0:0:ffff:8015:cd7d
128.21.205.126 0:0:0:0:0:ffff:8015:cd7e
128.21.205.127 0:0:0:0:0:ffff:8015:cd7f
128.21.205.128 0:0:0:0:0:ffff:8015:cd80
128.21.205.129 0:0:0:0:0:ffff:8015:cd81
128.21.205.130 0:0:0:0:0:ffff:8015:cd82
128.21.205.131 0:0:0:0:0:ffff:8015:cd83
128.21.205.132 0:0:0:0:0:ffff:8015:cd84
128.21.205.133 0:0:0:0:0:ffff:8015:cd85
128.21.205.134 0:0:0:0:0:ffff:8015:cd86
128.21.205.135 0:0:0:0:0:ffff:8015:cd87
128.21.205.136 0:0:0:0:0:ffff:8015:cd88
128.21.205.137 0:0:0:0:0:ffff:8015:cd89
128.21.205.138 0:0:0:0:0:ffff:8015:cd8a
128.21.205.139 0:0:0:0:0:ffff:8015:cd8b
128.21.205.140 0:0:0:0:0:ffff:8015:cd8c
128.21.205.141 0:0:0:0:0:ffff:8015:cd8d
128.21.205.142 0:0:0:0:0:ffff:8015:cd8e
128.21.205.143 0:0:0:0:0:ffff:8015:cd8f
128.21.205.144 0:0:0:0:0:ffff:8015:cd90
128.21.205.145 0:0:0:0:0:ffff:8015:cd91
128.21.205.146 0:0:0:0:0:ffff:8015:cd92
128.21.205.147 0:0:0:0:0:ffff:8015:cd93
128.21.205.148 0:0:0:0:0:ffff:8015:cd94
128.21.205.149 0:0:0:0:0:ffff:8015:cd95
128.21.205.150 0:0:0:0:0:ffff:8015:cd96
128.21.205.151 0:0:0:0:0:ffff:8015:cd97
128.21.205.152 0:0:0:0:0:ffff:8015:cd98
128.21.205.153 0:0:0:0:0:ffff:8015:cd99
128.21.205.154 0:0:0:0:0:ffff:8015:cd9a
128.21.205.155 0:0:0:0:0:ffff:8015:cd9b
128.21.205.156 0:0:0:0:0:ffff:8015:cd9c
128.21.205.157 0:0:0:0:0:ffff:8015:cd9d
128.21.205.158 0:0:0:0:0:ffff:8015:cd9e
128.21.205.159 0:0:0:0:0:ffff:8015:cd9f
128.21.205.160 0:0:0:0:0:ffff:8015:cda0
128.21.205.161 0:0:0:0:0:ffff:8015:cda1
128.21.205.162 0:0:0:0:0:ffff:8015:cda2
128.21.205.163 0:0:0:0:0:ffff:8015:cda3
128.21.205.164 0:0:0:0:0:ffff:8015:cda4
128.21.205.165 0:0:0:0:0:ffff:8015:cda5
128.21.205.166 0:0:0:0:0:ffff:8015:cda6
128.21.205.167 0:0:0:0:0:ffff:8015:cda7
128.21.205.168 0:0:0:0:0:ffff:8015:cda8
128.21.205.169 0:0:0:0:0:ffff:8015:cda9
128.21.205.170 0:0:0:0:0:ffff:8015:cdaa
128.21.205.171 0:0:0:0:0:ffff:8015:cdab
128.21.205.172 0:0:0:0:0:ffff:8015:cdac
128.21.205.173 0:0:0:0:0:ffff:8015:cdad
128.21.205.174 0:0:0:0:0:ffff:8015:cdae
128.21.205.175 0:0:0:0:0:ffff:8015:cdaf
128.21.205.176 0:0:0:0:0:ffff:8015:cdb0
128.21.205.177 0:0:0:0:0:ffff:8015:cdb1
128.21.205.178 0:0:0:0:0:ffff:8015:cdb2
128.21.205.179 0:0:0:0:0:ffff:8015:cdb3
128.21.205.180 0:0:0:0:0:ffff:8015:cdb4


128.21.205.181 0:0:0:0:0:ffff:8015:cdb5
128.21.205.182 0:0:0:0:0:ffff:8015:cdb6
128.21.205.183 0:0:0:0:0:ffff:8015:cdb7
128.21.205.184 0:0:0:0:0:ffff:8015:cdb8
128.21.205.185 0:0:0:0:0:ffff:8015:cdb9
128.21.205.186 0:0:0:0:0:ffff:8015:cdba
128.21.205.187 0:0:0:0:0:ffff:8015:cdbb
128.21.205.188 0:0:0:0:0:ffff:8015:cdbc
128.21.205.189 0:0:0:0:0:ffff:8015:cdbd
128.21.205.190 0:0:0:0:0:ffff:8015:cdbe
128.21.205.191 0:0:0:0:0:ffff:8015:cdbf
128.21.205.192 0:0:0:0:0:ffff:8015:cdc0
128.21.205.193 0:0:0:0:0:ffff:8015:cdc1
128.21.205.194 0:0:0:0:0:ffff:8015:cdc2
128.21.205.195 0:0:0:0:0:ffff:8015:cdc3
128.21.205.196 0:0:0:0:0:ffff:8015:cdc4
128.21.205.197 0:0:0:0:0:ffff:8015:cdc5
128.21.205.198 0:0:0:0:0:ffff:8015:cdc6
128.21.205.199 0:0:0:0:0:ffff:8015:cdc7
128.21.205.200 0:0:0:0:0:ffff:8015:cdc8
128.21.205.201 0:0:0:0:0:ffff:8015:cdc9
128.21.205.202 0:0:0:0:0:ffff:8015:cdca
128.21.205.203 0:0:0:0:0:ffff:8015:cdcb
128.21.205.204 0:0:0:0:0:ffff:8015:cdcc
128.21.205.205 0:0:0:0:0:ffff:8015:cdcd
128.21.205.206 0:0:0:0:0:ffff:8015:cdce
128.21.205.207 0:0:0:0:0:ffff:8015:cdcf
128.21.205.208 0:0:0:0:0:ffff:8015:cdd0
128.21.205.209 0:0:0:0:0:ffff:8015:cdd1
128.21.205.210 0:0:0:0:0:ffff:8015:cdd2
128.21.205.211 0:0:0:0:0:ffff:8015:cdd3
128.21.205.212 0:0:0:0:0:ffff:8015:cdd4
128.21.205.213 0:0:0:0:0:ffff:8015:cdd5
128.21.205.214 0:0:0:0:0:ffff:8015:cdd6
128.21.205.215 0:0:0:0:0:ffff:8015:cdd7
128.21.205.216 0:0:0:0:0:ffff:8015:cdd8
128.21.205.217 0:0:0:0:0:ffff:8015:cdd9
128.21.205.218 0:0:0:0:0:ffff:8015:cdda
128.21.205.219 0:0:0:0:0:ffff:8015:cddb
128.21.205.220 0:0:0:0:0:ffff:8015:cddc
128.21.205.221 0:0:0:0:0:ffff:8015:cddd
128.21.205.222 0:0:0:0:0:ffff:8015:cdde
128.21.205.223 0:0:0:0:0:ffff:8015:cddf
128.21.205.224 0:0:0:0:0:ffff:8015:cde0
128.21.205.225 0:0:0:0:0:ffff:8015:cde1
128.21.205.226 0:0:0:0:0:ffff:8015:cde2
128.21.205.227 0:0:0:0:0:ffff:8015:cde3
128.21.205.228 0:0:0:0:0:ffff:8015:cde4
128.21.205.229 0:0:0:0:0:ffff:8015:cde5
128.21.205.230 0:0:0:0:0:ffff:8015:cde6
128.21.205.231 0:0:0:0:0:ffff:8015:cde7
128.21.205.232 0:0:0:0:0:ffff:8015:cde8
128.21.205.233 0:0:0:0:0:ffff:8015:cde9
128.21.205.234 0:0:0:0:0:ffff:8015:cdea
128.21.205.235 0:0:0:0:0:ffff:8015:cdeb
128.21.205.236 0:0:0:0:0:ffff:8015:cdec
128.21.205.237 0:0:0:0:0:ffff:8015:cded
128.21.205.238 0:0:0:0:0:ffff:8015:cdee
128.21.205.239 0:0:0:0:0:ffff:8015:cdef
128.21.205.240 0:0:0:0:0:ffff:8015:cdf0
128.21.205.241 0:0:0:0:0:ffff:8015:cdf1
128.21.205.242 0:0:0:0:0:ffff:8015:cdf2
128.21.205.243 0:0:0:0:0:ffff:8015:cdf3
128.21.205.244 0:0:0:0:0:ffff:8015:cdf4
128.21.205.245 0:0:0:0:0:ffff:8015:cdf5
128.21.205.246 0:0:0:0:0:ffff:8015:cdf6
128.21.205.247 0:0:0:0:0:ffff:8015:cdf7
128.21.205.248 0:0:0:0:0:ffff:8015:cdf8
128.21.205.249 0:0:0:0:0:ffff:8015:cdf9
128.21.205.250 0:0:0:0:0:ffff:8015:cdfa
128.21.205.251 0:0:0:0:0:ffff:8015:cdfb
128.21.205.252 0:0:0:0:0:ffff:8015:cdfc
128.21.205.253 0:0:0:0:0:ffff:8015:cdfd
128.21.205.254 0:0:0:0:0:ffff:8015:cdfe
128.21.205.255 0:0:0:0:0:ffff:8015:cdff


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.