How can I detect if the user is on localhost in PHP?

Question

In other words, how can I tell if the person using my web application is on the server it resides on? If I remember correctly, PHPMyAdmin does something like this for securi

Answer 1

I found a easy answer.

Because all local drives have C: or D: or F: ... etc.

Just detect if the second character is a :

if ( substr_compare(getcwd(),":",1,1) == 0)
{
echo '<script type="text/javascript">alert(" The working dir is at the local computer ")</script>';
    $client_or_server = 'client';
}
else
{
echo '<script type="text/javascript">alert(" The working dir is at the server ")</script>';
    $client_or_server = 'server';
}

Answer 2

How about to compare $_SERVER['SERVER_ADDR'] === $_SERVER['REMOTE_ADDR'] to determine if client is on the same machine as server?

Answer 3

$_SERVER["REMOTE_ADDR"] should tell you the user's IP. It's spoofable, though.

Check this bounty question for a very detailed discussion.

I think what you remember with PHPMyAdmin is something different: Many MySQL Servers are configured so that they can only be accessed from localhost for security reasons.