sendmail, 4th Edition

Policy Rule Set Reference

Beginning with V8.8, sendmail calls special rule sets internally to determine its behavior. Called the policy rule sets, they are used for such varied tasks as setting spam handling, setting policy, or validating the conditions when ETRN should be allowed, to list just a few. Table 19-2 shows the complete list of these policy rule sets. Note that we merely summarize them here, and that some are described in detail in other chapters. Those that we describe here are detailed in the following sections.

Table 19-2. The policy rule sets

Rule set	§	Hook	Description
authinfo	Authinfo and the access database (V8.12 and later) on page 195	None	Handle AuthInfo: lookups in the access database.
check_compat	The check_compat Rule Set on page 259	See below	Validate just before delivery.
check_data	check_data on page 705	None needed	Check just after DATA.
check_eoh	The check_eoh Rule Set on page 1135	None needed	Validate after headers are read.
check_eom	The check_eom Rule Set on page 258	None needed	Review message’s size (V8.13 and later).
check_etrn	check_etrn on page 706	None needed	Allow or disallow ETRN.
check_expn	check_vrfy and check_expn on page 707	None needed	Validate EXPN.
check_mail	Local_check_mail and check_mail on page 255	Local_check_mail	Validate the envelope-sender address.
check_rcpt	Local_check_rcpt and check_rcpt on page 257	Local_check_rcpt	Validate the envelope-recipient address.
check_relay	Local_check_relay ...