very cute and impressively short, thanks for sharing this one

. . . I should be more familiar with the PHP standard library. I didn't know you could do reverse DNS in a single function call like that!

I've got good news, and I've got bad news:
The universe is merely a figment of my imagination.
Now are you ready for the bad news?

What if the passed in email address has no @ sign?

check for '@' 's exitence is mandatory for to avoid errors before go for validating the email address.

Regards,
Kumar S
GuyFromChennai.com

You should check results before making a negative rating on a snippet.

Via http://us3.php.net/checkdnsrr, checkdnsrr() will return either TRUE or FALSE; true for success, and false for everything else.

If you do a list($var1, $var2) = explode('@', $string) and there is no '@', then $var2 will be null.

If you then turn around and do checkdnsrr($var2, 'MX'), then the result will be FALSE; as expected. So therefore, this snippet does work and does work correctly.

What if a domain doesn't have an MX record? It would return FALSE correct?

I added checkdnsrr for windows here awhile ago as well for you stubborn windows developers like me =)

The php.net page for checkdnsrr() says "This function is not implemented on Windows platforms. Try the » PEAR class » Net_DNS."

Will this script work on a Windows server?

I guess this will work in windows implementing what you previously uploaded here:

http://bytemycode.com/snippets/snippet/377/

I would add the code above to this script as a revision or comment.

I'm glad that most of you found this snippet useful.