php-获得ip

//客户端ip
function get_client_ip(){
    if ($_SERVER['REMOTE_ADDR']) {
        $cip = $_SERVER['REMOTE_ADDR'];
    } 
    elseif (getenv("REMOTE_ADDR")) {
        $cip = getenv("REMOTE_ADDR");
    } 
    elseif (getenv("HTTP_CLIENT_IP")) {
        $cip = getenv("HTTP_CLIENT_IP");
    } 
    else {
        $cip = "unknown";
    }
    return $cip;
}



// 服务器端IP
 function serverIP(){   
  return gethostbyname($_SERVER["SERVER_NAME"]);   
 } 
 
 /**
 * 获取客户端IP地址
 * @param integer $type 返回类型 0 返回IP地址 1 返回IPV4地址数字
 * @param boolean $adv 是否进行高级模式获取（有可能被伪装）
 * @return mixed
 */
function get_client_ip($type = 0,$adv=false) {
    $type = $type ? 1 : 0;
    static $ip = NULL;
    if ($ip !== NULL) return $ip[$type];
    if($adv){
        if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            $arr = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
            $pos = array_search('unknown',$arr);
            if(false !== $pos) unset($arr[$pos]);
            $ip = trim($arr[0]);
        }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
            $ip = $_SERVER['HTTP_CLIENT_IP'];
        }elseif (isset($_SERVER['REMOTE_ADDR'])) {
            $ip = $_SERVER['REMOTE_ADDR'];
        }
    }elseif (isset($_SERVER['REMOTE_ADDR'])) {
        $ip = $_SERVER['REMOTE_ADDR'];
    }
    // IP地址合法验证
    $long = sprintf("%u",ip2long($ip));
    $ip = $long ? array($ip, $long) : array('0.0.0.0', 0);
    return $ip[$type];
}


$num_ip = ip2long($ip); IPv4地址转换成数字格式
long2ip($num_ip);       IPv4地址转换成字符串格式
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