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Sendmail, 3rd Edition by Bryan Costales

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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

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