| 掩碼位數 | 子網數 | 十進制掩碼 | IP 數 | 參考可用IP數(網絡號-廣播地址) | |||
| 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段對應表
| IP總數 | 子網掩碼 | C段個數 | |
| /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
代表一整個C段
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .0 | .1-.254 | .255 |
/25 -- 2 Subnets -- 126 Hosts/Subnet
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .0 | .1-.126 | .127 |
| .128 | .129-.254 | .255 |
26 -- 4 Subnets -- 62 Hosts/Subnet
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .0 | .1-.62 | .63 |
| .64 | .65-.126 | .127 |
| .128 | .129-.190 | .191 |
| .192 | .193-.254 | .255 |
/27 -- 8 Subnets -- 30 Hosts/Subnet
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .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
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .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
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .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
| 網絡地址 | 可用IP范圍 | 廣播地址 |
|---|---|---|
| .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 |
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