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<!-- dns ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<h2 id=dns>DNS</h2>
<p>
IPv4 name resolution functions
<a href=#toip><tt>dns.toip</tt></a>
and
<a href=#tohostname><tt>dns.tohostname</tt></a>
return <em>all</em> information obtained from
the resolver in a table of the form:
</p>
<blockquote><tt>
resolved4 = {<br>
name = <i>canonic-name</i>,<br>
alias = <i>alias-list</i>,<br>
ip = <i>ip-address-list</i><br>
}
</tt> </blockquote>
<p>
Note that the <tt>alias</tt> list can be empty.
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<p>
The more general name resolution function
<a href=#getaddrinfo><tt>dns.getaddrinfo</tt></a>, which
supports both IPv6 and IPv4,
returns <em>all</em> information obtained from
the resolver in a table of the form:
</p>
<blockquote><tt>
resolved6 = {<br>
[1] = {<br>
family = <i>family-name-1</i>,<br>
addr = <i>address-1</i><br>
},<br>
...<br>
[n] = {<br>
family = <i>family-name-n</i>,<br>
addr = <i>address-n</i><br>
}<br>
}
</tt> </blockquote>
<p>
Here, <tt>family</tt> contains the string <tt>"inet"</tt> for IPv4
addresses, and <tt>"inet6"</tt> for IPv6 addresses.
</p>
<!-- getaddrinfo ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=getaddrinfo>
socket.dns.<b>getaddrinfo(</b>address<b>)</b>
</p>
<p class=description>
Converts from host name to address.
</p>
<p class=parameters>
<tt>Address</tt> can be an IPv4 or IPv6 address or host name.
</p>
<p class=return>
The function returns a table with all information returned by
the resolver. In case of error, the function returns <b><tt>nil</tt></b>
followed by an error message.
</p>
<!-- gethostname ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=gethostname>
socket.dns.<b>gethostname()</b>
</p>
<p class=description>
Returns the standard host name for the machine as a string.
</p>
<!-- tohostname +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=tohostname>
socket.dns.<b>tohostname(</b>address<b>)</b>
</p>
<p class=description>
Converts from IPv4 address to host name.
</p>
<p class=parameters>
<tt>Address</tt> can be an IP address or host name.
</p>
<p class=return>
The function returns a string with the canonic host name of the given
<tt>address</tt>, followed by a table with all information returned by
the resolver. In case of error, the function returns <b><tt>nil</tt></b>
followed by an error message.
</p>
<!-- toip +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
<p class=name id=toip>
socket.dns.<b>toip(</b>address<b>)</b>
</p>
<p class=description>
Converts from host name to IPv4 address.
</p>
<p class=parameters>
<tt>Address</tt> can be an IP address or host name.
</p>
<p class=return>
Returns a string with the first IP address found for <tt>address</tt>,
followed by a table with all information returned by the resolver.
In case of error, the function returns <b><tt>nil</tt></b> followed by an error
message.
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<small>
Last modified by Diego Nehab on <br>
Thu Apr 20 00:25:07 EDT 2006
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