掩码位数 子网数 十进制掩码 IP 数 参考可用IP数(网络号-广播地址) 0 1 0 0 0 0 4294967296 4294967294 1 2 128 0 0 0 2147483648 2147483646 2 4 192 0 0 0 1073741824 1073741822 3 8 224 0 0 0 536870912 536870910 4 16 240 0 0 0 268435456 268435454 5 32 248 0 0 0 134217728 134217726 6 64 252 0 0 0 67108864 67108862 7 128 254 0 0 0 33554432 33554430 8 256 255 0 0 0 16777216 16777214 9 512 255 128 0 0 8388608 8388606 10 1024 255 192 0 0 4194304 4194302 11 2048 255 224 0 0 2097152 2097150 12 4096 255 240 0 0 1048576 1048574 13 8192 255 248 0 0 524288 524286 14 16384 255 252 0 0 262144 262142 15 32768 255 254 0 0 131072 131070 16 65536 255 255 0 0 65536 65534 17 131072 255 255 128 0 32768 32766 18 262144 255 255 192 0 16384 16382 19 524288 255 255 224 0 8192 8190 20 1048576 255 255 240 0 4096 4094 21 2097152 255 255 248 0 2048 2046 22 4194304 255 255 252 0 1024 1022 23 8388608 255 255 254 0 512 510 24 16777216 255 255 255 0 256 254 25 33554432 255 255 255 128 128 126 26 67108864 255 255 255 192 64 62 27 134217728 255 255 255 224 32 30 28 268435456 255 255 255 240 16 14 29 536870912 255 255 255 248 8 6 30 1073741824 255 255 255 252 4 2 31 2147483648 255 255 255 254 2 32 4294967296 255 255 255 255 1

IP段对应表

IP总数 子网掩码 C段个数 /30 4 255.255.255.252 1/64 /29 8 255.255.255.248 1/32 /28 16 255.255.255.240 1/16 /27 32 255.255.255.224 1/8 /26 64 255.255.255.192 1/4 /24 256 255.255.255.0 1 /23 512 255.255.254.0 2 /22 1024 255.255.252.0 4 /21 2048 255.255.248.0 8 /20 4096 255.255.240.0 16 /19 8192 255.255.224.0 32 /18 16384 255.255.192.0 64 /17 32768 255.255.128.0 128 /16 65536 255.255.0.0 256

24 --1 Subnets -- 254 Hosts/Subnet
代表一整个C段

网络地址 可用IP范围 广播地址 .0 .1-.254 .255

/25 -- 2 Subnets -- 126 Hosts/Subnet

网络地址 可用IP范围 广播地址 .0 .1-.126 .127 .128 .129-.254 .255

26 -- 4 Subnets -- 62 Hosts/Subnet

网络地址 可用IP范围 广播地址 .0 .1-.62 .63 .64 .65-.126 .127 .128 .129-.190 .191 .192 .193-.254 .255

/27 -- 8 Subnets -- 30 Hosts/Subnet

网络地址 可用IP范围 广播地址 .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

网络地址 可用IP范围 广播地址 .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

网络地址 可用IP范围 广播地址 .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 .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

网络地址 可用IP范围 广播地址 .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 .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 .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