Fax access rules The key strength of the email to fax gateway, is its ability to con- trol who can fax from where. Various access controls may be used to make sure the fax system does not get out of hand. Be aware that the fax system itself has its own access control. 11.. IIDD Each fax rule has an ID -- a string which will be referenced in the fax aliases and fax zones. 22.. HHooww ddooeess iitt wwoorrkk?? The email to fax gateway is a work in progress. Here is a small explanation of the access control mechanism it proposes. This may evolve in the future. So, comments are welcome. 22..11.. AAcccceessss ccoonnttrrooll An access rule may be open or selective. Mostly, you can specify whether faxes are accepted from anywhere, only from the local net, only from fax users, or only from a member of the user list. 22..22.. UUsseerr aauutthheennttiiccaattiioonn You may require that email from fax users be PGP signed, so you are sure they came from that user.