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| <h4 class="subsection">16.6.2 Host Addresses</h4> |
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| <p>Each computer on the Internet has one or more <dfn>Internet addresses</dfn>, |
| numbers which identify that computer among all those on the Internet. |
| Users typically write IPv4 numeric host addresses as sequences of four |
| numbers, separated by periods, as in ‘<samp><span class="samp">128.52.46.32</span></samp>’, and IPv6 |
| numeric host addresses as sequences of up to eight numbers separated by |
| colons, as in ‘<samp><span class="samp">5f03:1200:836f:c100::1</span></samp>’. |
| |
| <p>Each computer also has one or more <dfn>host names</dfn>, which are strings |
| of words separated by periods, as in ‘<samp><span class="samp">mescaline.gnu.org</span></samp>’. |
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| <p>Programs that let the user specify a host typically accept both numeric |
| addresses and host names. To open a connection a program needs a |
| numeric address, and so must convert a host name to the numeric address |
| it stands for. |
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| <ul class="menu"> |
| <li><a accesskey="1" href="Abstract-Host-Addresses.html#Abstract-Host-Addresses">Abstract Host Addresses</a>: What a host number consists of. |
| <li><a accesskey="2" href="Host-Address-Data-Type.html#Host-Address-Data-Type">Data type</a>: Data type for a host number. |
| <li><a accesskey="3" href="Host-Address-Functions.html#Host-Address-Functions">Functions</a>: Functions to operate on them. |
| <li><a accesskey="4" href="Host-Names.html#Host-Names">Names</a>: Translating host names to host numbers. |
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