Попробуй так:


if (isSet($_SERVER))
{
if (isSet($_SERVER["HTTP_X_FORWARDED_FOR"]))
{
$realip = $_SERVER["HTTP_X_FORWARDED_FOR"];
}
elseif (isSet($_SERVER["HTTP_CLIENT_IP"]))
{
$realip = $_SERVER["HTTP_CLIENT_IP"];
}
else
{
$realip = $_SERVER["REMOTE_ADDR"];
}
}
else
{
if ( getenv( 'HTTP_X_FORWARDED_FOR' ) )
{
$realip = getenv( 'HTTP_X_FORWARDED_FOR' );
}
elseif ( getenv( 'HTTP_CLIENT_IP' ) )
{
$realip = getenv( 'HTTP_CLIENT_IP' );
}
else
{
$realip = getenv( 'REMOTE_ADDR' );
}
}
$user_reg_id = $realip;
$user_reg_host = gethostbyaddr($realip);