1. Setting the Permissions
How to Give the Internet user permission to access the database

2. Setting the IUSR Permission
To give the Internet user permission to access the database, you need to give the IUSR_xxx account full control over the database and the folder in which the database resides.
Replace xxx by your computer’s windows name.
If you do not know what xxx is, you can find out as follows.

3. How to Learn the IUSR Name
In windows explorer, right-click the file or folder name, choose properties, and click the security tab.
On the security tab, click the Add button, then click the Advanced button, and click the Find Now button.
Peruse the list and you will see the name that begins with IUSR_.