sendmail 8.13 Companion

Chapter 7. Handle Spam and Filter with Milter

What’s New with V8.13

V8.13 has been augmented in several ways that benefit your ability to detect and reject spam email.

• The confREJECT_MSG mc macro no longer auto-inserts quotation marks around its value (Section 7.1.1 ^[V8.13]).

• Envelope quarantining has been added as a means to hold mail for review. (See Section 11.1.2 ^[V8.13] for a complete discussion of quarantining.)

• The Milter library has been enhanced by the addition of a smfi_quarantine( ) routine (Section 7.1.2.1 ^[V8.13]), a smfi_progress( ) routine (Section 7.1.2.2 ^[V8.13]), a smfi_stop( ) routine (Section 7.1.2.3 ^[V8.13]), a smfi_setdbg( ) routine (Section 7.1.2.4 ^[V8.13]), a smfi_setmlreply( ) routine (Section 7.1.2.5 ^[V8.13]), a smfi_setbacklog( ) routine (Section 7.1.2.6 ^[V8.13]) and a smfi_opensocket( ) routine(Section 7.1.2.7[V8.13]). Support for a 421 SMTP return (Section 7.1.2.9 ^[V8.13]) has been added, the removal of the socket by root (Section 7.1.2.10[V8.13]) has been prevented, and macros may now be passed to a Milter’s end-of-message routine (Section 24.1.17 ^[V8.13]).

• The check_relay ruleset (7.1.1^[3ed]) is now called with the value of ${client_name} macro (21.9.20[3ed]) so that it can deal with bogus DNS entries (Section 9.1.2 ^[V8.13]).

• The new greet_pause feature allows protection from SMTP slamming (Section 7.1.3 ^[V8.13]).

• The new (experimental) mtamark feature implements MTA marking by looking up TXT records in the in-addr.arpa domain (Section 7.1.4 ^[V8.13]