Sendmail, 3rd 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, just to list 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	Section 10.9.3.2	none	Handle AuthInfo: lookups in the access database
check_compat	Section 7.1.4	see below	Validate just before delivery
check_data	check_data	none needed	Check just after DATA
check_eoh	Section 25.5.3	none needed	Validate after headers are read
check_etrn	check_etrn	none needed	Allow or disallow ETRN
check_expn	check_vrfy and check_expn	none needed	Validate EXPN
check_mail	Section 7.1.2	Local_check_mail	Validate the envelope-sender address
check_rcpt	Section 7.1.3	Local_check_rcpt	Validate the envelope-recipient address
check_relay	Section 7.1.1	Local_check_relay	Validate incoming network connections
check_vrfy	check_vrfy and check_expn	none needed	Validate VRFY
queuegroup	Section 11.4.5	see below	Select a queue group
srv_features	srv_features	none needed	Tune server setting based on connection information
tls_client