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Server Address vs DNS

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Join Date: Jan 2009

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finance-blog finance-blog is offline

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Server Address vs DNS

Jan 2nd, 2009

I have some code that is called from with other files, using readfile so there is no referer etc.

To authenticate that the request is where it should be from, the php is passed a calling url as part of it parameters.

The idea is that I can then check the calling IP is from the correct machine. This works fine in most cases, however on some machines (I'm guessing VPS) the Server address is not what the DNS returns even though the domain name is hosted on that PC.

Here is my code.

 Help with Code Tags 
 PHP Syntax (Toggle Plain Text) 
$ip = gethostbyname($domain);
 
if ($ip != $_SERVER["REMOTE_ADDR"])
{	echo "URL does not match requesting IP address<br>\n";
	echo "$domain - $ip<br>\n";
	echo $_SERVER["REMOTE_ADDR"]."<br>\n";
	exit;
}
$ip = gethostbyname($domain);

if ($ip != $_SERVER["REMOTE_ADDR"])
{	echo "URL does not match requesting IP address<br>\n";
	echo "$domain - $ip<br>\n";
	echo $_SERVER["REMOTE_ADDR"]."<br>\n";
	exit;
}

In theory the REMOTE_ADDR and the IP returned from gethostbyname should match but they don't anybody any ideas how to get round this?

Last edited by finance-blog; Jan 2nd, 2009 at 4:02 pm.

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Join Date: Dec 2007

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hakimkal

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Re: Server Address vs DNS

Jan 3rd, 2009

try these line and see what you get?

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
<?php
 
$hostname = gethostbyaddr($_SERVER['REMOTE_ADDR']) ;
 
?>
<?php

$hostname = gethostbyaddr($_SERVER['REMOTE_ADDR']) ;

?>

best of luck with the job.

Last edited by peter_budo; Jan 6th, 2009 at 2:14 pm. Reason: Code tag correction please [code=php] instead of [code syntax="php"]

abdoolherkym!

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Join Date: Jan 2009

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finance-blog finance-blog is offline

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Re: Server Address vs DNS

Jan 4th, 2009

Surely on a shared serverm that would just give you the name of the shared server, not the domain name that is calling you.

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Join Date: Sep 2005

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Re: Server Address vs DNS

Jan 6th, 2009

The domain probably has more then one IP.

Try:

http://www.php.net/manual/en/functio...ostbynamel.php

and do a in_array() on the list of IPs.
http://www.php.net/in_array

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Join Date: Sep 2005

Posts: 1,050

Reputation: digital-ether is just really nice

Solved Threads: 65

digital-ether digital-ether is offline

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Re: Server Address vs DNS

Jan 6th, 2009

Also take a look at:
http://pear.php.net/package/Net_DNS

Works with windows also.

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