Question : checkdnsrr
 

has anyone implemented the PHP: checkdnsrr in register.php
or if someone knows how to can they post information on this please

PHP: checkdnsrr is a useful way to check MX records upon registration
and would like to see this implemented

That doesn't seem like it would be too hard, but reading the docs for that function, it looks like it only checks for the existence of an MX record, which might catch a completely made up domain name but wouldn't do much else. It seems like if that's a concern you might as well use email verification.