Saber si el servidor en realidad esta caído o es nuestra pc o conexión de internet.
Si no tienes un enlace de cerca para ir a un sitio y ver si un servidor esta caído, te dejo un código PHP que tiene la función de indicar los dicho anteriormente.
<html>
<head>
<style>
body
{
background-color:#FFF;
font-family: Verdana;
color: #000;
}
input{
-moz-border-radius: 3px;
font-family: Verdana;
background-color: #FFF;
border: 1px solid #CCC;
color: #000;
font-size: 25px;
margin: 3px;
padding: 3px;
}
#sin_borde
{
border-width:0;
cursor:pointer;
display:block;
font-family: Verdana;
}
td
{
font-size: 25px;
font-family: Verdana;
}
</style>
<title>Averigua si un servidor esta caído o eres tu!</title>
</head>
<body>
<center>
<?php
/**
*
*
* @author Daniel Godoy
* @copyright 2011
* @Site www.0x3a.com.ar www.remoteexecution.com.ar www.delincuentedital.com.ar
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
**/
set_time_limit(0);
$url=htmlentities($_POST['url']);
if(isset($url)&&($url!= "")
{
$online = @fsockopen($url, 80);
if ($online)
{
echo '¡Eres tú, <a href="http://'.$url.'" target=_blank>'.$url.'</a> está funcionando ok!
<br><a href="'.$_SERVER['PHP_SELF'].'">¿Deseas chequear otro sitio?</a>
';
} else {
echo '¡No, no eres tú! <a href="http://'.$url.'" target=_blank>'.$url.'</a> está caído.
<br><a href="'.$_SERVER['PHP_SELF'].'">¿Deseas chequear otro sitio?</a>
';
}
}else{
echo '
<form name="pr" action="" method="post">
<table align="center">
<td>¿<input id="boton" type="text" name="url" size="15" maxlength="300" value=""/> ESTA CAIDO..</td>
<td></td>
<td><input type="submit" name="submit" id="sin_borde" value="O SOY YO?" /></td>
</table>
';
}
?>
</center>
</body>
</html>