EFS is a 'POP3 Connector'. It retrieves email from a single pop3 mailbox at your Internet Provider (which holds mail for all addresses at your domain) and redirects messages to mailboxes on your local SMTP Mail Server (such as Microsoft Exchange or Lotus DOMINO)
The FREE Standard version does NOT have a user or time limitation and will work under most circumstances. You only need to register the Advanced or Advanced Plus versions if you require additional features available.