Sharepoint user validating
If the purpose of your Web site is for members of a particular workgroup to share documents and information, you typically add members of that workgroup (that is, their Windows user accounts or Windows groups) to an appropriate Share Point group on your site.For example, you can add workgroup members that you want to allow to contribute to your Web site to the Site name Members Share Point group. You can also add other members of the workgroup to the Site name Visitors Share Point group so that they can read documents and view lists, but not contribute to the site.As a site owner, you can either add Windows user accounts directly to your site or add them to Share Point groups to manage user accounts at the top-level Web site or subsite level.Conversely, you can also remove Windows user accounts and domain groups from your site and Share Point groups.Inside an organization, this typically means that site owners select Windows user accounts and Windows security groups from the organization's list (typically users or groups on the Windows domain) and add them to the site or a Share Point group of their choice.For example, Share Point groups can contain Windows domain groups (such as domain name\Department_A, where domain name is the name of the Windows domain) or individual users with a user account on the local server or in a Windows domain (such as domain name\user name).Three Share Point groups are provided by default, as shown in the following table.Note that you can customize them by assigning any permission level to them that you want, and you can also create new Share Point groups with the permission levels that you want.
Windows Share Point Services 3.0 enables you, as a site owner, to control what users or groups of users can access your Share Point sites.
This effectively transfers the task of managing users from the server administrator to site owners.
Windows Share Point Services 3.0 uses Windows users and domain groups and Windows authentication mechanisms to manage and authenticate users.
Note: Although you can, for example, assign the Design permission level to the Site name Readers Share Point group, it is more practical to create a new custom Share Point group and assign the permission level you need to that new group.
This way, you won't have Share Point group names that imply a different permission level than they actually have.