IPv4 subnet/CIDR table from OccupytheWeb on Twitter: “Network Basics for Hackers: Subnetting, Subnet Masks and CIDR Notation …”
Posted by jpluimers on 2024/11/27
I wrote about programs and scripts doing IPv4 subnet calculation, but sometimes it is easier to have a table at hand, so here is the one I found at [Wayback/Archive] OccupytheWeb on Twitter: “Network Basics for Hackers: Subnetting, Subnet Masks and CIDR Notation #networks #networkbasics #subnetting #infosec #networks4hackers #cyberwarrior #cyberwarrior #networkbasics #networkbasics subnet”
Notes:
- it is by far original, as a quick image search revealed lots of other sources, for instance the 2011 post [Wayback/Archive] Subnet Mask Quick Reference | Academic PCs Blog
- there is a much better table below adapted from Classless Inter-Domain Routing: IPv4 CIDR blocks – Wikipedia
Some earlier related posts:
- Bitcricket IP Subnet Calculator
- Getting your local IPv4 addresses, netmasks and CIDRs
- Getting the primary IP address (plain and CIDR) on Linux and OS X, then nmap scan on the associated subnet
And another example where the same table was used: [Wayback/Archive] tcpip – How to understand the “A subnet Example”? – Server Fault.
Since this one from Classless Inter-Domain Routing: IPv4 CIDR blocks – Wikipedia is much better, I copied it in full then colourised it using the above scheme and added the mask octet and binary mask columns, then added the “(max hosts)” to the “Decimal” columns:
IPv4 CIDR blocks
Address
formatDifference
to last addressMask Mask
octetBinary mask
in octetAddresses Relative
to class
A, B, CRestrictions
on a, b, c and d
(0..255 unless noted)Typical use Decimal
(max hosts)2n a.b.c.d/32 +0.0.0.0 255.255.255.255 4 11111111 1 20 1⁄256 C Host route a.b.c.d/31 +0.0.0.1 255.255.255.254 4 11111110 2 21 1⁄128 C d = 0 … (2n) … 254 Point-to-point links (RFC 3021) a.b.c.d/30 +0.0.0.3 255.255.255.252 4 11111100 4 22 1⁄64 C d = 0 … (4n) … 252 Point-to-point links (glue network) a.b.c.d/29 +0.0.0.7 255.255.255.248 4 11111000 8 23 1⁄32 C d = 0 … (8n) … 248 Smallest multi-host network a.b.c.d/28 +0.0.0.15 255.255.255.240 4 11110000 16 24 1⁄16 C d = 0 … (16n) … 240 Small LAN a.b.c.d/27 +0.0.0.31 255.255.255.224 4 11100000 32 25 ⅛ C d = 0 … (32n) … 224 a.b.c.d/26 +0.0.0.63 255.255.255.192 4 11000000 64 26 ¼ C d = 0, 64, 128, 192 a.b.c.d/25 +0.0.0.127 255.255.255.128 4 10000000 128 27 ½ C d = 0, 128 Large LAN a.b.c.0/24 +0.0.0.255 255.255.255.0 3 11111111 256 28 1 C a.b.c.0/23 +0.0.1.255 255.255.254.0 3 11111110 512 29 2 C c = 0 … (2n) … 254 a.b.c.0/22 +0.0.3.255 255.255.252.0 3 11111100 1,024 210 4 C c = 0 … (4n) … 252 Small business a.b.c.0/21 +0.0.7.255 255.255.248.0 3 11111000 2,048 211 8 C c = 0 … (8n) … 248 Small ISP/ large business a.b.c.0/20 +0.0.15.255 255.255.240.0 3 11110000 4,096 212 16 C c = 0 … (16n) … 240 a.b.c.0/19 +0.0.31.255 255.255.224.0 3 11100000 8,192 213 32 C c = 0 … (32n) … 224 ISP/ large business a.b.c.0/18 +0.0.63.255 255.255.192.0 3 11000000 16,384 214 64 C c = 0, 64, 128, 192 a.b.c.0/17 +0.0.127.255 255.255.128.0 3 10000000 32,768 215 128 C c = 0, 128 a.b.0.0/16 +0.0.255.255 255.255.0.0 2 11111111 65,536 216 256 C = B a.b.0.0/15 +0.1.255.255 255.254.0.0 2 11111110 131,072 217 2 B b = 0 … (2n) … 254 a.b.0.0/14 +0.3.255.255 255.252.0.0 2 11111100 262,144 218 4 B b = 0 … (4n) … 252 a.b.0.0/13 +0.7.255.255 255.248.0.0 2 11111000 524,288 219 8 B b = 0 … (8n) … 248 a.b.0.0/12 +0.15.255.255 255.240.0.0 2 11110000 1,048,576 220 16 B b = 0 … (16n) … 240 a.b.0.0/11 +0.31.255.255 255.224.0.0 2 11100000 2,097,152 221 32 B b = 0 … (32n) … 224 a.b.0.0/10 +0.63.255.255 255.192.0.0 2 11000000 4,194,304 222 64 B b = 0, 64, 128, 192 a.b.0.0/9 +0.127.255.255 255.128.0.0 2 10000000 8,388,608 223 128 B b = 0, 128 a.0.0.0/8 +0.255.255.255 255.0.0.0 1 11111111 16,777,216 224 256 B = A Largest IANA block allocation a.0.0.0/7 +1.255.255.255 254.0.0.0 1 11111110 33,554,432 225 2 A a = 0 … (2n) … 254 a.0.0.0/6 +3.255.255.255 252.0.0.0 1 11111100 67,108,864 226 4 A a = 0 … (4n) … 252 a.0.0.0/5 +7.255.255.255 248.0.0.0 1 11111000 134,217,728 227 8 A a = 0 … (8n) … 248 a.0.0.0/4 +15.255.255.255 240.0.0.0 1 11110000 268,435,456 228 16 A a = 0 … (16n) … 240 a.0.0.0/3 +31.255.255.255 224.0.0.0 1 11100000 536,870,912 229 32 A a = 0 … (32n) … 224 a.0.0.0/2 +63.255.255.255 192.0.0.0 1 11000000 1,073,741,824 230 64 A a = 0, 64, 128, 192 a.0.0.0/1 +127.255.255.255 128.0.0.0 1 10000000 2,147,483,648 231 128 A a = 0, 128 0.0.0.0/0 +255.255.255.255 0.0.0.0 0 00000000 4,294,967,296 232 256 A Entire IPv4 Internet, default route.
If you want to modify the table even further, please fork https://gist.github.com/jpluimers/d2665ef16ed20ec9b8266bf154c56830
For now it is hosted as HTML page at https://gist.githack.com/jpluimers/d2665ef16ed20ec9b8266bf154c56830/raw/27cd4c0583771198c65e68f21ee9968c1af64827/IPv4-CIDR-blocks.html
I posted a bitmap of it at [Wayback/Archive] Jeroen Wiert Pluimers on Twitter: “@three_cube For now the HTML is served at …”
–jeroen
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| <html xmlns="http://www.w3.org/1999/xhtml" lang="en" class="wf-inactive"><head profile="http://gmpg.org/xfn/11"> | |
| <body> | |
| <h1><span id="IPv4_CIDR_blocks" class="mw-headline">IPv4 CIDR blocks</span></h1> | |
| <table class="wikitable" rules="all"> | |
| <tbody> | |
| <tr> | |
| <th rowspan="2">Address<br> | |
| format</th> | |
| <th rowspan="2">Difference<br> | |
| to last address</th> | |
| <th rowspan="2">Mask</th> | |
| <th rowspan="2">Mask<br> | |
| octet</th> | |
| <th rowspan="2">Binary mask<br> | |
| in octet</th> | |
| <th colspan="2">Addresses</th> | |
| <th rowspan="2">Relative<br> | |
| to class<br> | |
| A, B, C</th> | |
| <th rowspan="2">Restrictions<br> | |
| on <i>a</i>, <i>b</i>, <i>c</i> and <i>d</i><br> | |
| <small>(0..255 unless noted)</small></th> | |
| <th rowspan="2">Typical use</th> | |
| </tr> | |
| <tr> | |
| <th>Decimal<br> | |
| (max hosts)</th> | |
| <th bgcolor="lightgreen">2<sup><i>n</i></sup></th> | |
| </tr> | |
| <tr bgcolor="lightyellow"> | |
| <td><i><span class="ipaddr">a.b.c.d/32</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.0</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">255</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:#ff0000;">11111111</span></td> | |
| <td>1</td> | |
| <td>2<sup>0</sup></td> | |
| <td><span class="frac" role="math"><span class="num">1</span>⁄<span class="den">256</span></span> C</td> | |
| <td></td> | |
| <td>Host route</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/31</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.1</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">254</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">11111110</span></td> | |
| <td>2</td> | |
| <td bgcolor="lightgreen">2<sup>1</sup></td> | |
| <td><span class="frac" role="math"><span class="num">1</span>⁄<span class="den">128</span></span> C</td> | |
| <td><i>d</i> = 0 … (2<i>n</i>) … 254</td> | |
| <td>Point-to-point links (<a class="mw-redirect" title="RFC (identifier)" href="https://en.wikipedia.org/wiki/RFC_(identifier)">RFC</a> <a class="external text" href="https://datatracker.ietf.org/doc/html/rfc3021" rel="nofollow">3021</a>)</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/30</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.3</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">252</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">11111100</span></td> | |
| <td>4</td> | |
| <td bgcolor="lightgreen">2<sup>2</sup></td> | |
| <td><span class="frac" role="math"><span class="num">1</span>⁄<span class="den">64</span></span> C</td> | |
| <td><i>d</i> = 0 … (4<i>n</i>) … 252</td> | |
| <td><span class="nowrap">Point-to-point links (glue network)</span></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/29</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.7</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">248</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">11111000</span></td> | |
| <td>8</td> | |
| <td bgcolor="lightgreen">2<sup>3</sup></td> | |
| <td><span class="frac" role="math"><span class="num">1</span>⁄<span class="den">32</span></span> C</td> | |
| <td><i>d</i> = 0 … (8<i>n</i>) … 248</td> | |
| <td>Smallest multi-host network</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/28</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.15</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">240</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">11110000</span></td> | |
| <td>16</td> | |
| <td bgcolor="lightgreen">2<sup>4</sup></td> | |
| <td><span class="frac" role="math"><span class="num">1</span>⁄<span class="den">16</span></span> C</td> | |
| <td><i>d</i> = 0 … (16<i>n</i>) … 240</td> | |
| <td rowspan="3">Small <a class="mw-redirect" title="LAN" href="https://en.wikipedia.org/wiki/LAN">LAN</a></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/27</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.31</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">224</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">11100000</span></td> | |
| <td>32</td> | |
| <td bgcolor="lightgreen">2<sup>5</sup></td> | |
| <td>⅛ C</td> | |
| <td><i>d</i> = 0 … (32<i>n</i>) … 224</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/26</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.63</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">192</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">11000000</span></td> | |
| <td>64</td> | |
| <td bgcolor="lightgreen">2<sup>6</sup></td> | |
| <td>¼ C</td> | |
| <td><i>d</i> = 0, 64, 128, 192</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.d/25</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.127</span></i></td> | |
| <td><i><span class="ipaddr">255.255.255.<span style="color:red;">128</span></span></i></td> | |
| <td>4</td> | |
| <td><span style="color:red;">10000000</span></td> | |
| <td>128</td> | |
| <td bgcolor="lightgreen">2<sup>7</sup></td> | |
| <td>½ C</td> | |
| <td><i>d</i> = 0, 128</td> | |
| <td rowspan="2">Large <a class="mw-redirect" title="LAN" href="https://en.wikipedia.org/wiki/LAN">LAN</a></td> | |
| </tr> | |
| <tr bgcolor="lightyellow"> | |
| <td><i><span class="ipaddr">a.b.c.0/24</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.0.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">255</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11111111</span></td> | |
| <td>256</td> | |
| <td>2<sup>8</sup></td> | |
| <td>1 C</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/23</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.1.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">254</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11111110</span></td> | |
| <td>512</td> | |
| <td bgcolor="lightgreen">2<sup>9</sup></td> | |
| <td>2 C</td> | |
| <td><i>c</i> = 0 … (2<i>n</i>) … 254</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/22</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.3.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">252</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11111100</span></td> | |
| <td>1,024</td> | |
| <td bgcolor="lightgreen">2<sup>10</sup></td> | |
| <td>4 C</td> | |
| <td><i>c</i> = 0 … (4<i>n</i>) … 252</td> | |
| <td>Small business</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/21</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.7.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">248</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11111000</span></td> | |
| <td>2,048</td> | |
| <td bgcolor="lightgreen">2<sup>11</sup></td> | |
| <td>8 C</td> | |
| <td><i>c</i> = 0 … (8<i>n</i>) … 248</td> | |
| <td rowspan="2">Small <a class="mw-redirect" title="ISP" href="https://en.wikipedia.org/wiki/ISP">ISP</a>/ large business</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/20</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.15.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">240</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11110000</span></td> | |
| <td>4,096</td> | |
| <td bgcolor="lightgreen">2<sup>12</sup></td> | |
| <td>16 C</td> | |
| <td><i>c</i> = 0 … (16<i>n</i>) … 240</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/19</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.31.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">224</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11100000</span></td> | |
| <td>8,192</td> | |
| <td bgcolor="lightgreen">2<sup>13</sup></td> | |
| <td>32 C</td> | |
| <td><i>c</i> = 0 … (32<i>n</i>) … 224</td> | |
| <td rowspan="3"><a class="mw-redirect" title="ISP" href="https://en.wikipedia.org/wiki/ISP">ISP</a>/ large business</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/18</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.63.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">192</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">11000000</span></td> | |
| <td>16,384</td> | |
| <td bgcolor="lightgreen">2<sup>14</sup></td> | |
| <td>64 C</td> | |
| <td><i>c</i> = 0, 64, 128, 192</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.c.0/17</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.127.255</span></i></td> | |
| <td><i><span class="ipaddr">255.255.<span style="color:red;">128</span>.0</span></i></td> | |
| <td>3</td> | |
| <td><span style="color:red;">10000000</span></td> | |
| <td>32,768</td> | |
| <td bgcolor="lightgreen">2<sup>15</sup></td> | |
| <td>128 C</td> | |
| <td><i>c</i> = 0, 128</td> | |
| </tr> | |
| <tr bgcolor="lightyellow"> | |
| <td><i><span class="ipaddr">a.b.0.0/16</span></i></td> | |
| <td>+<i><span class="ipaddr">0.0.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">255</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11111111</span></td> | |
| <td>65,536</td> | |
| <td>2<sup>16</sup></td> | |
| <td>256 C = B</td> | |
| <td></td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/15</span></i></td> | |
| <td>+<i><span class="ipaddr">0.1.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">254</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11111110</span></td> | |
| <td>131,072</td> | |
| <td bgcolor="lightgreen">2<sup>17</sup></td> | |
| <td>2 B</td> | |
| <td><i>b</i> = 0 … (2<i>n</i>) … 254</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/14</span></i></td> | |
| <td>+<i><span class="ipaddr">0.3.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">252</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11111100</span></td> | |
| <td>262,144</td> | |
| <td bgcolor="lightgreen">2<sup>18</sup></td> | |
| <td>4 B</td> | |
| <td><i>b</i> = 0 … (4<i>n</i>) … 252</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/13</span></i></td> | |
| <td>+<i><span class="ipaddr">0.7.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">248</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11111000</span></td> | |
| <td>524,288</td> | |
| <td bgcolor="lightgreen">2<sup>19</sup></td> | |
| <td>8 B</td> | |
| <td><i>b</i> = 0 … (8<i>n</i>) … 248</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/12</span></i></td> | |
| <td>+<i><span class="ipaddr">0.15.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">240</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11110000</span></td> | |
| <td>1,048,576</td> | |
| <td bgcolor="lightgreen">2<sup>20</sup></td> | |
| <td>16 B</td> | |
| <td><i>b</i> = 0 … (16<i>n</i>) … 240</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/11</span></i></td> | |
| <td>+<i><span class="ipaddr">0.31.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">224</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11100000</span></td> | |
| <td>2,097,152</td> | |
| <td bgcolor="lightgreen">2<sup>21</sup></td> | |
| <td>32 B</td> | |
| <td><i>b</i> = 0 … (32<i>n</i>) … 224</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/10</span></i></td> | |
| <td>+<i><span class="ipaddr">0.63.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">192</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">11000000</span></td> | |
| <td>4,194,304</td> | |
| <td bgcolor="lightgreen">2<sup>22</sup></td> | |
| <td>64 B</td> | |
| <td><i>b</i> = 0, 64, 128, 192</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.b.0.0/9</span></i></td> | |
| <td>+<i><span class="ipaddr">0.127.255.255</span></i></td> | |
| <td><i><span class="ipaddr">255.<span style="color:red;">128</span>.0.0</span></i></td> | |
| <td>2</td> | |
| <td><span style="color:red;">10000000</span></td> | |
| <td>8,388,608</td> | |
| <td bgcolor="lightgreen">2<sup>23</sup></td> | |
| <td>128 B</td> | |
| <td><i>b</i> = 0, 128</td> | |
| <td></td> | |
| </tr> | |
| <tr bgcolor="lightyellow"> | |
| <td><i><span class="ipaddr">a.0.0.0/8</span></i></td> | |
| <td>+<i><span class="ipaddr">0.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">255</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11111111</span></td> | |
| <td>16,777,216</td> | |
| <td>2<sup>24</sup></td> | |
| <td>256 B = A</td> | |
| <td></td> | |
| <td>Largest <a title="Internet Assigned Numbers Authority" href="https://en.wikipedia.org/wiki/Internet_Assigned_Numbers_Authority">IANA</a> block allocation</td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/7</span></i></td> | |
| <td>+<i><span class="ipaddr">1.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">254</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11111110</span></td> | |
| <td>33,554,432</td> | |
| <td bgcolor="lightgreen">2<sup>25</sup></td> | |
| <td>2 A</td> | |
| <td><i>a</i> = 0 … (2<i>n</i>) … 254</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/6</span></i></td> | |
| <td>+<i><span class="ipaddr">3.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">252</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11111100</span></td> | |
| <td>67,108,864</td> | |
| <td bgcolor="lightgreen">2<sup>26</sup></td> | |
| <td>4 A</td> | |
| <td><i>a</i> = 0 … (4<i>n</i>) … 252</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/5</span></i></td> | |
| <td>+<i><span class="ipaddr">7.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">248</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11111000</span></td> | |
| <td>134,217,728</td> | |
| <td bgcolor="lightgreen">2<sup>27</sup></td> | |
| <td>8 A</td> | |
| <td><i>a</i> = 0 … (8<i>n</i>) … 248</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/4</span></i></td> | |
| <td>+<i><span class="ipaddr">15.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">240</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11110000</span></td> | |
| <td>268,435,456</td> | |
| <td bgcolor="lightgreen">2<sup>28</sup></td> | |
| <td>16 A</td> | |
| <td><i>a</i> = 0 … (16<i>n</i>) … 240</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/3</span></i></td> | |
| <td>+<i><span class="ipaddr">31.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">224</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11100000</span></td> | |
| <td>536,870,912</td> | |
| <td bgcolor="lightgreen">2<sup>29</sup></td> | |
| <td>32 A</td> | |
| <td><i>a</i> = 0 … (32<i>n</i>) … 224</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/2</span></i></td> | |
| <td>+<i><span class="ipaddr">63.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">192</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">11000000</span></td> | |
| <td>1,073,741,824</td> | |
| <td bgcolor="lightgreen">2<sup>30</sup></td> | |
| <td>64 A</td> | |
| <td><i>a</i> = 0, 64, 128, 192</td> | |
| <td></td> | |
| </tr> | |
| <tr> | |
| <td><i><span class="ipaddr">a.0.0.0/1</span></i></td> | |
| <td>+<i><span class="ipaddr">127.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr"><span style="color:red;">128</span>.0.0.0</span></i></td> | |
| <td>1</td> | |
| <td><span style="color:red;">10000000</span></td> | |
| <td>2,147,483,648</td> | |
| <td bgcolor="lightgreen">2<sup>31</sup></td> | |
| <td>128 A</td> | |
| <td><i>a</i> = 0, 128</td> | |
| <td></td> | |
| </tr> | |
| <tr bgcolor="lightyellow"> | |
| <td><i><span class="ipaddr">0.0.0.0/0</span></i></td> | |
| <td>+<i><span class="ipaddr">255.255.255.255</span></i></td> | |
| <td><i><span class="ipaddr">0.0.0.0</span></i></td> | |
| <td>0</td> | |
| <td>00000000</td> | |
| <td>4,294,967,296</td> | |
| <td>2<sup>32</sup></td> | |
| <td>256 A</td> | |
| <td></td> | |
| <td>Entire IPv4 Internet, <a title="Default route" href="https://en.wikipedia.org/wiki/Default_route">default route</a>.</td> | |
| </tr> | |
| </tbody> | |
| </table> | |
| </body> | |
| </html> |
The Wiert Corner - irregular stream of stuff 
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