title: WebService authentication via default MembershipProvider
body: <p>What is the best practice when you need to authenticate specific <code>OperationContracts</code>, while using the default <code>MembershipProvider</code> for security (<code>FormsAuthentication</code>).</p>
  
  <p>I guess that doing <code>Membership.ValidateUser</code> and <code>Membership.GetUser</code> just won't cut it when using WebServices, right?</p>
  
  <p>In other words: How can I verify that a user is allowed to use specific methods in the webservice (that the user is authenticated/"logged on")?</p>