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Posted by Jerry Stuckle on 09/09/07 14:16
Aaron Saray wrote:
> On Sep 8, 11:04 am, "J.O. Aho" <u...@example.net> wrote:
>> Rob wrote:
>>> Just wondering how sites capture a visitor's IP address and how this is
>>> done in PHP?
>> There is a page which lists PHP global variables, these are useful to know,http://www.php.net/manual/en/reserved.variables.php
>>
>> As you see $_SERVER['REMOTE_ADDR'] will hold the remote users IP-address (if
>> the remote user is using a proxy, then it's the proxy IP-address you get).
>>
>> So in your code you can use:
>>
>> <?PHP
>> $userip=$_SERVER['REMOTE_ADDR'];
>>
>> echo "This is your ip-number: {$userip}<br>";
>>
>> //File we want to store the ip-number to
>> //se to have this file already.
>> $filename = 'storeipnumbers.txt';
>> if (is_writable($filename)) {
>> if (!$handle = fopen($filename, 'a')) {
>> echo "Cannot open file ($filename)";
>> exit;
>> }
>> if (fwrite($handle, $userip) === FALSE) {
>> echo "Cannot write to file ($filename)";
>> exit;
>> }
>> fclose($handle);
>> echo "We have stored ip-number '{$userip}' to file '{$filename}'";} else {
>>
>> echo "Sorry, we couldn't store the following ip-number: {$userip}<br>";}
>>
>> ?>
>>
>> This script displays the ip-number and stores it to a file called
>> storeipnumbers.txt.
>> --
>>
>> //Aho
>
> Users can also have a proxied IP address. This is what I use to
> figure out the IP addresses (its from a class - hence $this):
>
> /**
> * Get user ip
> *
> * Get user's ip and also proxy if it exists.
> */
> protected function _getIP()
> {
>
> /**
> * Check for http forwarding proxy
> */
> if (!empty($_SERVER['HTTP_X_FORWARDED_FOR']) || !
> empty($_SERVER['HTTP_CLIENT_IP'])) {
>
> /**
> * REMOTE_ADDR would be the proxy IP
> */
> if (!empty($_SERVER['REMOTE_ADDR'])) {
> $this->_proxyIP = $_SERVER['REMOTE_ADDR'];
> }
>
> /**
> * HTTP_X_FORWARDED_FOR would be the user's ip.
> */
> if (empty($_SERVER['HTTP_X_FORWARDED_FOR']) &&
> empty($_SERVER['HTTP_CLIENT_IP'])) {
>
> /**
> * not set, so set our user ip to our proxy's ip as
> well (or all NULL even)
> */
> $this->_userIP = $this->_proxyIP;
> }
>
> /**
> * get our proxy ip
> */
> elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
> $this->_userIP = $_SERVER['HTTP_X_FORWARDED_FOR'];
> }
> elseif (!empty($_SERVER['HTTP_CLIENT_IP'])) {
> $this->_userIP = $_SERVER['HTTP_CLIENT_IP'];
> }
> }
>
> /**
> * not proxied
> */
> else {
>
> /**
> * if we can detect ip
> */
> if (isset($_SERVER['REMOTE_ADDR'])) {
> $this->_userIP = $_SERVER['REMOTE_ADDR'];
> }
> }
> }
>
Which only works if the proxy actually adds the forwarded tag.
Anonymous proxies do not, and there is no way of telling where they came
from.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
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