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
18.21.121.1 0:0:0:0:0:ffff:1215:7901
18.21.121.2 0:0:0:0:0:ffff:1215:7902
18.21.121.3 0:0:0:0:0:ffff:1215:7903
18.21.121.4 0:0:0:0:0:ffff:1215:7904
18.21.121.5 0:0:0:0:0:ffff:1215:7905
18.21.121.6 0:0:0:0:0:ffff:1215:7906
18.21.121.7 0:0:0:0:0:ffff:1215:7907
18.21.121.8 0:0:0:0:0:ffff:1215:7908
18.21.121.9 0:0:0:0:0:ffff:1215:7909
18.21.121.10 0:0:0:0:0:ffff:1215:790a
18.21.121.11 0:0:0:0:0:ffff:1215:790b
18.21.121.12 0:0:0:0:0:ffff:1215:790c
18.21.121.13 0:0:0:0:0:ffff:1215:790d
18.21.121.14 0:0:0:0:0:ffff:1215:790e
18.21.121.15 0:0:0:0:0:ffff:1215:790f
18.21.121.16 0:0:0:0:0:ffff:1215:7910
18.21.121.17 0:0:0:0:0:ffff:1215:7911
18.21.121.18 0:0:0:0:0:ffff:1215:7912
18.21.121.19 0:0:0:0:0:ffff:1215:7913
18.21.121.20 0:0:0:0:0:ffff:1215:7914
18.21.121.21 0:0:0:0:0:ffff:1215:7915
18.21.121.22 0:0:0:0:0:ffff:1215:7916
18.21.121.23 0:0:0:0:0:ffff:1215:7917
18.21.121.24 0:0:0:0:0:ffff:1215:7918
18.21.121.25 0:0:0:0:0:ffff:1215:7919
18.21.121.26 0:0:0:0:0:ffff:1215:791a
18.21.121.27 0:0:0:0:0:ffff:1215:791b
18.21.121.28 0:0:0:0:0:ffff:1215:791c
18.21.121.29 0:0:0:0:0:ffff:1215:791d
18.21.121.30 0:0:0:0:0:ffff:1215:791e
18.21.121.31 0:0:0:0:0:ffff:1215:791f
18.21.121.32 0:0:0:0:0:ffff:1215:7920
18.21.121.33 0:0:0:0:0:ffff:1215:7921
18.21.121.34 0:0:0:0:0:ffff:1215:7922
18.21.121.35 0:0:0:0:0:ffff:1215:7923
18.21.121.36 0:0:0:0:0:ffff:1215:7924
18.21.121.37 0:0:0:0:0:ffff:1215:7925
18.21.121.38 0:0:0:0:0:ffff:1215:7926
18.21.121.39 0:0:0:0:0:ffff:1215:7927
18.21.121.40 0:0:0:0:0:ffff:1215:7928
18.21.121.41 0:0:0:0:0:ffff:1215:7929
18.21.121.42 0:0:0:0:0:ffff:1215:792a
18.21.121.43 0:0:0:0:0:ffff:1215:792b
18.21.121.44 0:0:0:0:0:ffff:1215:792c
18.21.121.45 0:0:0:0:0:ffff:1215:792d
18.21.121.46 0:0:0:0:0:ffff:1215:792e
18.21.121.47 0:0:0:0:0:ffff:1215:792f
18.21.121.48 0:0:0:0:0:ffff:1215:7930
18.21.121.49 0:0:0:0:0:ffff:1215:7931
18.21.121.50 0:0:0:0:0:ffff:1215:7932
18.21.121.51 0:0:0:0:0:ffff:1215:7933
18.21.121.52 0:0:0:0:0:ffff:1215:7934
18.21.121.53 0:0:0:0:0:ffff:1215:7935
18.21.121.54 0:0:0:0:0:ffff:1215:7936
18.21.121.55 0:0:0:0:0:ffff:1215:7937
18.21.121.56 0:0:0:0:0:ffff:1215:7938
18.21.121.57 0:0:0:0:0:ffff:1215:7939
18.21.121.58 0:0:0:0:0:ffff:1215:793a
18.21.121.59 0:0:0:0:0:ffff:1215:793b
18.21.121.60 0:0:0:0:0:ffff:1215:793c


18.21.121.61 0:0:0:0:0:ffff:1215:793d
18.21.121.62 0:0:0:0:0:ffff:1215:793e
18.21.121.63 0:0:0:0:0:ffff:1215:793f
18.21.121.64 0:0:0:0:0:ffff:1215:7940
18.21.121.65 0:0:0:0:0:ffff:1215:7941
18.21.121.66 0:0:0:0:0:ffff:1215:7942
18.21.121.67 0:0:0:0:0:ffff:1215:7943
18.21.121.68 0:0:0:0:0:ffff:1215:7944
18.21.121.69 0:0:0:0:0:ffff:1215:7945
18.21.121.70 0:0:0:0:0:ffff:1215:7946
18.21.121.71 0:0:0:0:0:ffff:1215:7947
18.21.121.72 0:0:0:0:0:ffff:1215:7948
18.21.121.73 0:0:0:0:0:ffff:1215:7949
18.21.121.74 0:0:0:0:0:ffff:1215:794a
18.21.121.75 0:0:0:0:0:ffff:1215:794b
18.21.121.76 0:0:0:0:0:ffff:1215:794c
18.21.121.77 0:0:0:0:0:ffff:1215:794d
18.21.121.78 0:0:0:0:0:ffff:1215:794e
18.21.121.79 0:0:0:0:0:ffff:1215:794f
18.21.121.80 0:0:0:0:0:ffff:1215:7950
18.21.121.81 0:0:0:0:0:ffff:1215:7951
18.21.121.82 0:0:0:0:0:ffff:1215:7952
18.21.121.83 0:0:0:0:0:ffff:1215:7953
18.21.121.84 0:0:0:0:0:ffff:1215:7954
18.21.121.85 0:0:0:0:0:ffff:1215:7955
18.21.121.86 0:0:0:0:0:ffff:1215:7956
18.21.121.87 0:0:0:0:0:ffff:1215:7957
18.21.121.88 0:0:0:0:0:ffff:1215:7958
18.21.121.89 0:0:0:0:0:ffff:1215:7959
18.21.121.90 0:0:0:0:0:ffff:1215:795a
18.21.121.91 0:0:0:0:0:ffff:1215:795b
18.21.121.92 0:0:0:0:0:ffff:1215:795c
18.21.121.93 0:0:0:0:0:ffff:1215:795d
18.21.121.94 0:0:0:0:0:ffff:1215:795e
18.21.121.95 0:0:0:0:0:ffff:1215:795f
18.21.121.96 0:0:0:0:0:ffff:1215:7960
18.21.121.97 0:0:0:0:0:ffff:1215:7961
18.21.121.98 0:0:0:0:0:ffff:1215:7962
18.21.121.99 0:0:0:0:0:ffff:1215:7963
18.21.121.100 0:0:0:0:0:ffff:1215:7964
18.21.121.101 0:0:0:0:0:ffff:1215:7965
18.21.121.102 0:0:0:0:0:ffff:1215:7966
18.21.121.103 0:0:0:0:0:ffff:1215:7967
18.21.121.104 0:0:0:0:0:ffff:1215:7968
18.21.121.105 0:0:0:0:0:ffff:1215:7969
18.21.121.106 0:0:0:0:0:ffff:1215:796a
18.21.121.107 0:0:0:0:0:ffff:1215:796b
18.21.121.108 0:0:0:0:0:ffff:1215:796c
18.21.121.109 0:0:0:0:0:ffff:1215:796d
18.21.121.110 0:0:0:0:0:ffff:1215:796e
18.21.121.111 0:0:0:0:0:ffff:1215:796f
18.21.121.112 0:0:0:0:0:ffff:1215:7970
18.21.121.113 0:0:0:0:0:ffff:1215:7971
18.21.121.114 0:0:0:0:0:ffff:1215:7972
18.21.121.115 0:0:0:0:0:ffff:1215:7973
18.21.121.116 0:0:0:0:0:ffff:1215:7974
18.21.121.117 0:0:0:0:0:ffff:1215:7975
18.21.121.118 0:0:0:0:0:ffff:1215:7976
18.21.121.119 0:0:0:0:0:ffff:1215:7977
18.21.121.120 0:0:0:0:0:ffff:1215:7978


18.21.121.121 0:0:0:0:0:ffff:1215:7979
18.21.121.122 0:0:0:0:0:ffff:1215:797a
18.21.121.123 0:0:0:0:0:ffff:1215:797b
18.21.121.124 0:0:0:0:0:ffff:1215:797c
18.21.121.125 0:0:0:0:0:ffff:1215:797d
18.21.121.126 0:0:0:0:0:ffff:1215:797e
18.21.121.127 0:0:0:0:0:ffff:1215:797f
18.21.121.128 0:0:0:0:0:ffff:1215:7980
18.21.121.129 0:0:0:0:0:ffff:1215:7981
18.21.121.130 0:0:0:0:0:ffff:1215:7982
18.21.121.131 0:0:0:0:0:ffff:1215:7983
18.21.121.132 0:0:0:0:0:ffff:1215:7984
18.21.121.133 0:0:0:0:0:ffff:1215:7985
18.21.121.134 0:0:0:0:0:ffff:1215:7986
18.21.121.135 0:0:0:0:0:ffff:1215:7987
18.21.121.136 0:0:0:0:0:ffff:1215:7988
18.21.121.137 0:0:0:0:0:ffff:1215:7989
18.21.121.138 0:0:0:0:0:ffff:1215:798a
18.21.121.139 0:0:0:0:0:ffff:1215:798b
18.21.121.140 0:0:0:0:0:ffff:1215:798c
18.21.121.141 0:0:0:0:0:ffff:1215:798d
18.21.121.142 0:0:0:0:0:ffff:1215:798e
18.21.121.143 0:0:0:0:0:ffff:1215:798f
18.21.121.144 0:0:0:0:0:ffff:1215:7990
18.21.121.145 0:0:0:0:0:ffff:1215:7991
18.21.121.146 0:0:0:0:0:ffff:1215:7992
18.21.121.147 0:0:0:0:0:ffff:1215:7993
18.21.121.148 0:0:0:0:0:ffff:1215:7994
18.21.121.149 0:0:0:0:0:ffff:1215:7995
18.21.121.150 0:0:0:0:0:ffff:1215:7996
18.21.121.151 0:0:0:0:0:ffff:1215:7997
18.21.121.152 0:0:0:0:0:ffff:1215:7998
18.21.121.153 0:0:0:0:0:ffff:1215:7999
18.21.121.154 0:0:0:0:0:ffff:1215:799a
18.21.121.155 0:0:0:0:0:ffff:1215:799b
18.21.121.156 0:0:0:0:0:ffff:1215:799c
18.21.121.157 0:0:0:0:0:ffff:1215:799d
18.21.121.158 0:0:0:0:0:ffff:1215:799e
18.21.121.159 0:0:0:0:0:ffff:1215:799f
18.21.121.160 0:0:0:0:0:ffff:1215:79a0
18.21.121.161 0:0:0:0:0:ffff:1215:79a1
18.21.121.162 0:0:0:0:0:ffff:1215:79a2
18.21.121.163 0:0:0:0:0:ffff:1215:79a3
18.21.121.164 0:0:0:0:0:ffff:1215:79a4
18.21.121.165 0:0:0:0:0:ffff:1215:79a5
18.21.121.166 0:0:0:0:0:ffff:1215:79a6
18.21.121.167 0:0:0:0:0:ffff:1215:79a7
18.21.121.168 0:0:0:0:0:ffff:1215:79a8
18.21.121.169 0:0:0:0:0:ffff:1215:79a9
18.21.121.170 0:0:0:0:0:ffff:1215:79aa
18.21.121.171 0:0:0:0:0:ffff:1215:79ab
18.21.121.172 0:0:0:0:0:ffff:1215:79ac
18.21.121.173 0:0:0:0:0:ffff:1215:79ad
18.21.121.174 0:0:0:0:0:ffff:1215:79ae
18.21.121.175 0:0:0:0:0:ffff:1215:79af
18.21.121.176 0:0:0:0:0:ffff:1215:79b0
18.21.121.177 0:0:0:0:0:ffff:1215:79b1
18.21.121.178 0:0:0:0:0:ffff:1215:79b2
18.21.121.179 0:0:0:0:0:ffff:1215:79b3
18.21.121.180 0:0:0:0:0:ffff:1215:79b4


18.21.121.181 0:0:0:0:0:ffff:1215:79b5
18.21.121.182 0:0:0:0:0:ffff:1215:79b6
18.21.121.183 0:0:0:0:0:ffff:1215:79b7
18.21.121.184 0:0:0:0:0:ffff:1215:79b8
18.21.121.185 0:0:0:0:0:ffff:1215:79b9
18.21.121.186 0:0:0:0:0:ffff:1215:79ba
18.21.121.187 0:0:0:0:0:ffff:1215:79bb
18.21.121.188 0:0:0:0:0:ffff:1215:79bc
18.21.121.189 0:0:0:0:0:ffff:1215:79bd
18.21.121.190 0:0:0:0:0:ffff:1215:79be
18.21.121.191 0:0:0:0:0:ffff:1215:79bf
18.21.121.192 0:0:0:0:0:ffff:1215:79c0
18.21.121.193 0:0:0:0:0:ffff:1215:79c1
18.21.121.194 0:0:0:0:0:ffff:1215:79c2
18.21.121.195 0:0:0:0:0:ffff:1215:79c3
18.21.121.196 0:0:0:0:0:ffff:1215:79c4
18.21.121.197 0:0:0:0:0:ffff:1215:79c5
18.21.121.198 0:0:0:0:0:ffff:1215:79c6
18.21.121.199 0:0:0:0:0:ffff:1215:79c7
18.21.121.200 0:0:0:0:0:ffff:1215:79c8
18.21.121.201 0:0:0:0:0:ffff:1215:79c9
18.21.121.202 0:0:0:0:0:ffff:1215:79ca
18.21.121.203 0:0:0:0:0:ffff:1215:79cb
18.21.121.204 0:0:0:0:0:ffff:1215:79cc
18.21.121.205 0:0:0:0:0:ffff:1215:79cd
18.21.121.206 0:0:0:0:0:ffff:1215:79ce
18.21.121.207 0:0:0:0:0:ffff:1215:79cf
18.21.121.208 0:0:0:0:0:ffff:1215:79d0
18.21.121.209 0:0:0:0:0:ffff:1215:79d1
18.21.121.210 0:0:0:0:0:ffff:1215:79d2
18.21.121.211 0:0:0:0:0:ffff:1215:79d3
18.21.121.212 0:0:0:0:0:ffff:1215:79d4
18.21.121.213 0:0:0:0:0:ffff:1215:79d5
18.21.121.214 0:0:0:0:0:ffff:1215:79d6
18.21.121.215 0:0:0:0:0:ffff:1215:79d7
18.21.121.216 0:0:0:0:0:ffff:1215:79d8
18.21.121.217 0:0:0:0:0:ffff:1215:79d9
18.21.121.218 0:0:0:0:0:ffff:1215:79da
18.21.121.219 0:0:0:0:0:ffff:1215:79db
18.21.121.220 0:0:0:0:0:ffff:1215:79dc
18.21.121.221 0:0:0:0:0:ffff:1215:79dd
18.21.121.222 0:0:0:0:0:ffff:1215:79de
18.21.121.223 0:0:0:0:0:ffff:1215:79df
18.21.121.224 0:0:0:0:0:ffff:1215:79e0
18.21.121.225 0:0:0:0:0:ffff:1215:79e1
18.21.121.226 0:0:0:0:0:ffff:1215:79e2
18.21.121.227 0:0:0:0:0:ffff:1215:79e3
18.21.121.228 0:0:0:0:0:ffff:1215:79e4
18.21.121.229 0:0:0:0:0:ffff:1215:79e5
18.21.121.230 0:0:0:0:0:ffff:1215:79e6
18.21.121.231 0:0:0:0:0:ffff:1215:79e7
18.21.121.232 0:0:0:0:0:ffff:1215:79e8
18.21.121.233 0:0:0:0:0:ffff:1215:79e9
18.21.121.234 0:0:0:0:0:ffff:1215:79ea
18.21.121.235 0:0:0:0:0:ffff:1215:79eb
18.21.121.236 0:0:0:0:0:ffff:1215:79ec
18.21.121.237 0:0:0:0:0:ffff:1215:79ed
18.21.121.238 0:0:0:0:0:ffff:1215:79ee
18.21.121.239 0:0:0:0:0:ffff:1215:79ef
18.21.121.240 0:0:0:0:0:ffff:1215:79f0
18.21.121.241 0:0:0:0:0:ffff:1215:79f1
18.21.121.242 0:0:0:0:0:ffff:1215:79f2
18.21.121.243 0:0:0:0:0:ffff:1215:79f3
18.21.121.244 0:0:0:0:0:ffff:1215:79f4
18.21.121.245 0:0:0:0:0:ffff:1215:79f5
18.21.121.246 0:0:0:0:0:ffff:1215:79f6
18.21.121.247 0:0:0:0:0:ffff:1215:79f7
18.21.121.248 0:0:0:0:0:ffff:1215:79f8
18.21.121.249 0:0:0:0:0:ffff:1215:79f9
18.21.121.250 0:0:0:0:0:ffff:1215:79fa
18.21.121.251 0:0:0:0:0:ffff:1215:79fb
18.21.121.252 0:0:0:0:0:ffff:1215:79fc
18.21.121.253 0:0:0:0:0:ffff:1215:79fd
18.21.121.254 0:0:0:0:0:ffff:1215:79fe
18.21.121.255 0:0:0:0:0:ffff:1215:79ff


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.