You may want to protect this script using .htaccess so no one else can access it. Dont use a common name like backup.php or something like that. You can do the same for other files like admin.php etc...
You can protect the file name and restrict access, heres an example using the .htaccess file:
Code:
<Files backup.php>
order deny,allow
deny from all
allow from myisp.com
allow from 10.0.*
allow from *.myisp.com
</Files>
or
Code:
<Files /user/www/backup.php>
order deny,allow
deny from all
allow from myisp.com
allow from 10.0.*
allow from *.myisp.com
</Files>
You must be very carefull when having these type of scripts on your site. Make sure you secure the files.