When you enable SSL client authentication, you can require
clients to provide an encrypted user name and password using SSL.
You can also map certificates to client accounts for SSL version
3.0, which requires a certificate to authenticate the client.
In the console tree, right-click a virtual server, and then
On the Access tab, click Authentication.
Enable SSL client authentication must be selected. To
require all clients to authenticate over SSL, select Require SSL
To authenticate users from a client certificate, click
Enable client certificate mapping to Windows user accounts.
To relate the information contained in the certificate to a Windows
user account, click Client Mappings. Use the IIS dialog box
to map one-to-one or many-to-one certificates. For more information
on client certificate mapping, see the IIS documentation.