PHP获取客户端IP

/**
	  * 获取客户端ip
	  *
	  * @link http://www.cnblogs.com/belie8/articles/2368957.html
	  * @return string
	  * @author http://my.oschina.net/wuzhencan/blog
	  */
	 public function getClientIp(){
		 $ip = '';
		 $xip = $_SERVER['HTTP_X_FORWARDED_FOR'];
		 $cip = $_SERVER['HTTP_CLIENT_IP'];
		 $rip = $_SERVER['REMOTE_ADDR'];

		 //使用代理服务器情况
		 if($xip && strcasecmp($xip, 'unknown')) {
			 if(false !== strpos($xip,',')) {
				 $ipArr = explode(',',$xip);
				 foreach($ipArr as $val) {
					 if(trim(strtolower($val)) != 'unknown') {
						 $ip = $val;
						 break;
					 }
				 }
			 } else {
				 $ip = $xip;
			 }
		 } elseif($cip && strcasecmp($cip, 'unknown')) {
			 $ip = $cip;
		 } elseif($rip && strcasecmp($rip, 'unknown')) {
			 $ip = $rip;
		 }

		 preg_match("/[\d\.]{7,15}/", $ip, $match);
		 return $match[0] ? $match[0] : 'unknown';
	 }

参考链接：

http://www.cnblogs.com/belie8/articles/2368957.html