22

✏️ Editing: dns.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 
 "http://www.w3.org/TR/html4/strict.dtd">
<html>

<head>
<meta name="description" content="LuaSocket: DNS support">
<meta name="keywords" content="Lua, LuaSocket, DNS, Network, Library, Support">
<title>LuaSocket: DNS support</title>
<link rel="stylesheet" href="reference.css" type="text/css">
</head>

<body>

<div class=header>
<hr>
<center>
<table summary="LuaSocket logo">
<tr><td align=center><a href="http://www.lua.org">
<img width=128 height=128 border=0 alt="LuaSocket" src="luasocket.png">
</a></td></tr>
<tr><td align=center valign=top>Network support for the Lua language
</td></tr>
</table>

<a href="index.html">home</a> &middot;
<a href="index.html#download">download</a> &middot;
<a href="installation.html">installation</a> &middot;
<a href="introduction.html">introduction</a> &middot;
<a href="reference.html">reference</a> 

</center>
<hr>
</div>

IPv4 name resolution functions 
<a href=#toip><tt>dns.toip</tt></a>
and
<a href=#tohostname><tt>dns.tohostname</tt></a>
return all information obtained from 
the resolver in a table of the form:

<blockquote><tt>
resolved4 = { 
&nbsp;&nbsp;name = canonic-name, 
&nbsp;&nbsp;alias = alias-list, 
&nbsp;&nbsp;ip = ip-address-list 
}
</tt> </blockquote>

Note that the <tt>alias</tt> list can be empty.

The more general name resolution function 
<a href=#getaddrinfo><tt>dns.getaddrinfo</tt></a>, which
supports both IPv6 and IPv4,
returns all information obtained from 
the resolver in a table of the form:

<blockquote><tt>
resolved6 = { 
&nbsp;&nbsp;[1] = { 
&nbsp;&nbsp;&nbsp;&nbsp;family = family-name-1, 
&nbsp;&nbsp;&nbsp;&nbsp;addr = address-1 
&nbsp;&nbsp;}, 
&nbsp;&nbsp;... 
&nbsp;&nbsp;[n] = { 
&nbsp;&nbsp;&nbsp;&nbsp;family = family-name-n, 
&nbsp;&nbsp;&nbsp;&nbsp;addr = address-n 
&nbsp;&nbsp;} 
}
</tt> </blockquote>

Here, <tt>family</tt> contains the string <tt>"inet"</tt> for IPv4
addresses, and <tt>"inet6"</tt> for IPv6 addresses.

socket.dns.getaddrinfo(address)

Converts from host name to address.

<tt>Address</tt> can be an IPv4 or IPv6 address or host name.

The function returns a table with all information returned by
the resolver. In case of error, the function returns <tt>nil</tt>
followed by an error message.

socket.dns.gethostname()

Returns the standard host name for the machine as a string.

socket.dns.tohostname(address)

Converts from IPv4 address to host name.

<tt>Address</tt> can be an IP address or host name.

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 <tt>nil</tt>
followed by an error message.

socket.dns.toip(address)

Converts from host name to IPv4 address.

<tt>Address</tt> can be an IP address or host name.

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 <tt>nil</tt> followed by an error
message.

<div class=footer>
<hr>
<center>

<a href="index.html">home</a> &middot;
<a href="index.html#down">download</a> &middot;
<a href="installation.html">installation</a> &middot;
<a href="introduction.html">introduction</a> &middot;
<a href="reference.html">reference</a>



Last modified by Diego Nehab on 
Thu Apr 20 00:25:07 EDT 2006


</center>
</div>

</body>
</html>

MR SKB