Integrated security is the minimum administration overhead option for SQL Server. This type of security enables you to map a set of Windows NT accounts to the SQL Server database, then it passes through the account of the logged on user to SQL Server for validation at data access. You are never prompted for a user account or password. If the logged-on user has no access, that user is denied access.
If you specified integrated security when you install SQL Server, SMS uses the account the user logged on with to access SQL Server. This account is generally used by the SMS services, because in SMS, WBEM and the SMS Provider control user access to the SQL Server database. In this case, no special accounts are required.
If you use SQL Server integrated security, keep in mind that if you grant a Windows NT user group access to the SMS site database, this permission is not dynamic. As new users are added to the Windows NT user group, they are not given SQL Server security rights unless you add them individually.
Specify a New SQL Server Account
About Standard Security in SQL Server
About the SQL Server Account
SMS Accounts Configuration Overview