There are several mapping tables that can be used to control who can or can not send mail, receive mail, or both. For general information on the format and usage of the PMDF mapping file, see Chapter 5. The SEND_ACCESS, ORIG_SEND_ACCESS, MAIL_ACCESS, ORIG_MAIL_ACCESS, and FROM_ACCESS mappings are described below. The nature of these mappings is very general and allows per channel granularity.
In the case of messages that come in channels where the underlying network connection is handled via the PMDF Dispatcher, including the PMDF multithreaded TCP SMTP channels, the Lotus Notes channels, and PMDF-XGS channels, there is a related mapping table, PORT_ACCESS, which can be used to block incoming connections based on IP number; see Section 23.2.1. Although the PORT_ACCESS mapping table does not allow for the fine level of granularity of the SEND_ACCESS and related mapping tables and applies only to certain channels, it is more efficient for what it does do, since it rejects a disallowed hosts' connection attempt at the TCP level, before the channel dialogue has even begun.
The MAIL_ACCESS and ORIG_MAIL_ACCESS mappings are the most general, having available not only the address and channel information available to SEND_ACCESS and ORIG_SEND_ACCESS, but also any information that would be available via the PORT_ACCESS mapping table, including IP address and port number information.