I need help, about what is going on with some PHP superglobals, and if someone can inform me as to what I am missing in the below statement.

I have a website which requires people to log in, and as a security feature, I collect the users IP address with $_SERVER['REMOTE_ADDR'] and I had felt that I had just found out that I could get the machine name also, or what that machine has set as their email address.

$_SERVER['SERVER_ADMIN'] is the one which always got my own email address during tests, and so I have started to use it.

It returns my hotmail email address, of which has no relation whatsoever to my website, which is hosted by an independent web hoster.

I have just looked at the database of three new members, and it contains my hotmail address for each of these members.


What is going on?

That variable is the value defined in the Apache virtual host definition as the contact person of the web site. Nothing to do with your users.

'SERVER_ADMIN' The value given to the SERVER_ADMIN (for Apache) directive in the web server configuration file. If the script is running on a virtual host, this will be the value defined for that virtual host.

There is a reference on those variables there:
http://www.php.net/manual/en/reserved.variables.php

The computer name is not available. On a small extent, the reverse DNS name can be found, by doing a reverse DNS query, but you'll end with the DNS name for the ip adress of the user, not the computer name.
For example, my computer name is "devLinux", and my reverse DNS name right now is "84-73-38-182.dclient.hispeed.ch."
It's usually combined by the reversed IP adress (it's a reverse DNS query after all) and the ISP domain name.

How would one get the 'reverse DNS' of a user in a PHP script?

php.net/manual/en/function.dns-get-record.php

Originally Posted by mtishetsky

php.net/manual/en/function.dns-get-record.php

I would have rather said gethostbyaddr(), but dns_get_Record() let you do the job too.

http://www.php.net/manual/en/function.gethostbyaddr.php