PHP Get Client IP_PHP Tutorial

1

2 // Example use of getenv()

3 $ip = getenv('REMOTE_ADDR');

4 // Or simply use a Superglobal ($_SERVER or $_ENV)

5 $ip = $_SERVER['REMOTE_ADDR'];

6 ?>

This is the method provided in the official PHP manual.

But when the Web server API is ASAPI (IIS), the getenv function does not work. In this case, if you use getenv to obtain the user's client IP, you will get the wrong IP address.

So the safer and more accurate way is to avoid using the getenv function as much as possible. For example, you can use the following function to obtain IP information:

01

02 function GetIP(){

03 if (getenv("HTTP_CLIENT_IP")

04    && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))

05 $ip = getenv("HTTP_CLIENT_IP");

06 else if (getenv("HTTP_X_FORWARDED_FOR")

07    && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))

08 $ip = getenv("HTTP_X_FORWARDED_FOR");

09 else if (getenv("REMOTE_ADDR")

10   && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))

11 $ip = getenv("REMOTE_ADDR");

12 else if (isset($_SERVER['REMOTE_ADDR'])

13                                                                                                                        

14                            && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))

15 $ip = $_SERVER['REMOTE_ADDR'];

16 else

17 $ip = "unknown";

18 return($ip);

19 }

20

21 $ip = GetIP();

22 echo $ip;

23 ?>

The difference between HTTP_X_FORWARDED_FOR, HTTP_VIA, REMOTE_ADDR is

1. Situation without using proxy server:

REMOTE_ADDR = your IP

HTTP_VIA = No value or www.2cto.com is not displayed
HTTP_X_FORWARDED_FOR = No value or no value

2. The use of transparent proxy servers: Transparent Proxies

REMOTE_ADDR = Last proxy server IP

HTTP_VIA = proxy server IP
HTTP_X_FORWARDED_FOR = Your real IP. When passing through multiple proxy servers, this value is similar to the following: 203.98.182.163, 203.98.182.163, 203.129.72.215.

This type of proxy server still forwards your information to your visitor, which cannot achieve the purpose of hiding your true identity.

3. The situation of using ordinary anonymous proxy servers: Anonymous Proxies

REMOTE_ADDR = Last proxy server IP

HTTP_VIA = proxy server IP
HTTP_X_FORWARDED_FOR = Proxy server IP. When passing through multiple proxy servers, this value is similar to the following: 203.98.182.163, 203.98.182.163, 203.129.72.215.

Hide your real IP, but reveal to your visitors that you are using a proxy server to access them.

4. The use of deceptive proxy servers: Distorting Proxies

REMOTE_ADDR = Proxy server IP

HTTP_VIA = proxy server IP
HTTP_X_FORWARDED_FOR = Random IP. When passing through multiple proxy servers, this value is similar to the following: 203.98.182.163, 203.98.182.163, 203.129.72.215.

Tell the visitor that you are using a proxy server, but make up a fake random IP instead of your real IP to trick it.

5. The use of high-anonymity proxy servers: High Anonymity Proxies (Elite proxies)

REMOTE_ADDR = Proxy server IP
HTTP_VIA = No value or not displayed
HTTP_X_FORWARDED_FOR = No value or not displayed. When passing through multiple proxy servers, this value is similar to the following: 203.98.182.163, 203.98.182.163, 203.129.72.215.

Completely replaces all your information with the proxy server's information, just like you are using that proxy server to directly access the object.

function getip(){
if($_SERVER['HTTP_X_FORWARDED_FOR']){
$online_ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
}elseif($_SERVER['HTTP_CLIENT_IP']){
$online_ip = $_SERVER['HTTP_CLIENT_IP'];
}else{
$online_ip = $_SERVER['REMOTE_ADDR'];
}
return $online_ip;
}

Excerpted from PPP

http://www.bkjia.com/PHPjc/478316.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/478316.htmlTechArticle1 ?php 2 // Example use of getenv() 3 $ip = getenv(REMOTE_ADDR); 4 // Or simply use a Superglobal ($_SERVER or $_ENV) 5 $ip = $_SERVER[REMOTE_ADDR]; 6 ? This is provided in the PHP official manual...