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HostsNetmaskSize of /24
/32(a)1255.255.255.255host
/31(b)2255.255.255.2541/128
/304255.255.255.2521/64
/298255.255.255.2481/32
/2816255.255.255.2401/16
/2732255.255.255.2241/8
/2664255.255.255.1921/4
/25(c)128255.255.255.1281/2
/24256255.255.255.01
/23512255.255.254.02
/221,024255.255.252.04
/212,048255.255.248.08
/204,096255.255.240.016
HostsNetmaskSize of /24
/198,192255.255.224.032
/1816,384255.255.192.064
/1732,768255.255.128.0128
/1665,536255.255.0.0256
/15131,072255.254.0.0512
/14262,144255.252.0.01,024
/13524,288255.248.0.02,048
/121,048,576255.240.0.04,096
/112,097,152255.224.0.08,192
/104,194,304255.192.0.016,384
/98,388,608255.128.0.032,768
/816,777,216255.0.0.065,536
/25 -- 2 Subnets -- 126 Hosts/Subnet
Network #IP RangeBroadcast
.0.1-.126.127
.128.129-.254.255
/26 -- 4 Subnets -- 62 Hosts/Subnet
Network #IP RangeBroadcast
.0.1-.62.63
.64.65-.126.127
.128.129-.190.191
.192.193-.254.255
/27 -- 8 Subnets -- 30 Hosts/Subnet
Network #IP RangeBroadcast
.0.1-.30.31
.32.33-.62.63
.64.65-.94.95
.96.97-.126.127
.128.129-.158.159
.160.161-.190.191
.192.193-.222.223
.224.225-.254.255
/28 -- 16 Subnets -- 14 Hosts/Subnet
Network #IP RangeBroadcast
.0.1-.14.15
.16.17-.30.31
.32.33-.46.47
.48.49-.62.63
.64.65-.78.79
.80.81-.94.95
.96.97-.110.111
.112.113-.126.127
.128.129-.142.143
.144.145-.158.159
.160.161-.174.175
.176.177-.190.191
.192.193-.206.207
.208.209-.222.223
.224.225-.238.239
.240.241-.254.255
/29 -- 32 Subnets -- 6 Hosts/Subnet
Network #IP RangeBroadcast
.0.1-.6.7
.8.9-.14.15
.16.17-.22.23
.24.25-.30.31
.32.33-.38.39
.40.41-.46.47
.48.49-.54.55
.56.57-.62.63
.64.65-.70.71
.72.73-.78.79
.80.81-.86.87
.88.89-.94.95
.96.97-.102.103
.104.105-.110.111
.112.113-.118.119
.120.121-.126.127
 
Network #IP RangeBroadcast
.128.129-.134.135
.136.137-.142.143
.144.145-.150.151
.152.153-.158.159
.160.161-.166.167
.168.169-.174.175
.176.177-.182.183
.184.185-.190.191
.192.193-.198.199
.200.201-.206.207
.208.209-.214.215
.216.217-.222.223
.224.225-.230.231
.232.233-.238.239
.240.241-.246.247
.248.249-.254.255
/30 -- 64 Subnets -- 2 Hosts/Subnet
Network #IP RangeBroadcast
.0.1-.2.3
.4.5-.6.7
.8.9-.10.11
.12.13-.14.15
.16.17-.18.19
.20.21-.22.23
.24.25-.26.27
.28.29-.30.31
.32.33-.34.35
.36.37-.38.39
.40.41-.42.43
.44.45-.46.47
.48.49-.50.51
.52.53-.54.55
.56.57-.58.59
.60.61-.62.63
.64.65-.66.67
.68.69-.70.71
.72.73-.74.75
.76.77-.78.79
.80.81-.82.83
.84.85-.86.87
 
Network #IP RangeBroadcast
.88.89-.90.91
.92.93-.94.95
.96.97-.98.99
.100.101-.102.103
.104.105-.106.107
.108.109-.110.111
.112.113-.114.115
.116.117-.118.119
.120.121-.122.123
.124.125-.126.127
.128.129-.130.131
.132.133-.134.135
.136.137-.138.139
.140.141-.142.143
.144.145-.146.147
.148.149-.150.151
.152.153-.154.155
.156.157-.158.159
.160.161-.162.163
.164.165-.166.167
.168.169-.170.171
.172.173-.174.175
 
Network #IP RangeBroadcast
.176.177-.178.179
.180.181-.182.183
.184.185-.186.187
.188.189-.190.191
.192.193-.194.195
.196.197-.198.199
.200.201-.202.203
.204.205-.206.207
.208.209-.210.211
.212.213-.214.215
.216.217-.218.219
.220.221-.222.223
.224.225-.226.227
.228.229-.230.231
.232.233-.234.235
.236.237-.238.239
.240.241-.242.243
.244.245-.246.247
.248.249-.250.251
.252.253-.254.255

Footnotes:
a) A /32 is only a single IP address

b) A /31 is an unusable network. The first IP is the network identifier. The last IP is the subnet identifier. This leaves no available IP's to assign.

c) A /25 was unusable before RFC 1878, released in October 1995. It was not acceptable to use a network that was all zeros or all ones. All modern equipment now accepts these networks, which is why you will find things such as the command 'ip subnet-zero' set by default on Cisco equipment.


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