PHP获取IP地址

echo getip();exit;
echo getIp();exit;
function getip() {
	$unknown = 'unknown';
	if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])&&$_SERVER['HTTP_X_FORWARDED_FOR']&&strcasecmp($_SERVER['HTTP_X_FORWARDED_FOR'],$unknown)){
		$ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
	} elseif ( isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], $unknown) ) {
		$ip = $_SERVER['REMOTE_ADDR'];
	}
	//处理多层代理的情况或者使用正则方式：$ip = preg_match("/[\d\.]{7,15}/", $ip, $matches) ? $matches[0] : $unknown;
	if (false !== strpos($ip, ',')){
	    $ip_arr=explode(',', $ip);
		$ip = reset($ip_arr);
	}
	return $ip;
}

function getIp(){
	if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown")){
		$ip = getenv("HTTP_CLIENT_IP");
	}else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown")){
		$ip = getenv("HTTP_X_FORWARDED_FOR");
	}else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown")){
		$ip = getenv("REMOTE_ADDR");
	}else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown")){
		$ip = $_SERVER['REMOTE_ADDR'];
	}else{
		$ip = "unknown";
	}
	return($ip);
}