It really depends on whether you would like to revoke access to your protected content at any stage or whether it is more important that your users or customers are able to view your documents or products offline (i.e. not connected to the Internet).
By forcing your customers to connect to the server for every access you can perform instant user or document revocation. If you select every n days you can only perform revocation after n days have elapsed since the customer last viewed the document.
The section of the protection panel (Expiry and Validity >> Check license validity) controls how often your customers must check with the Administration server to verify their license when opening a protected file.
- Never – Your customers never have to connect to the server in order to view your protected content. Your content can therefore always be viewed off-line and no connection to the Internet is ever required. This is an appropriate setting for a book or magazine.
Note: The first time your customers view your protected content (or the first they view content protected in a publication), the Viewer software always connects to the server to obtain the decryption key (this operation is transparent to the user). Subsequent checks with the server however are not made if this option is selected.
- Every n days – The value you select or enter here determines how many days your customers can stay offline before they need to connect to the Administration server in order to view your protected content again. Once this time period has elapsed they will not be able to view your content again until they let the Viewer software connect to the Administration server to validate their license.
You might select this option if you need to be able to suspend customers using publications when they have not paid their subscription.
- Each time the document is opened – Your customers must be online in order to view and use your protected content.
Before they can view your content they will need to let the Viewer software connect to the administration server (this operation is transparent to the user) to verify their continuing access rights.