sendmail 8.13 Companion

Chapter 19. The S (Rule Sets) Configuration Command

Rule sets in the configuration file, like subroutines in a program, control the sequence of steps sendmail uses to rewrite addresses. Inside each rule set is a series of zero or more individual rules. Rules are used to select the appropriate delivery agent for any particular address, to detect and reject addressing errors, to transform addresses to meet particular needs, to validate addresses and headers for the purpose of rejecting spam, and to make policy decisions.

What’s New with V8.13

V8.13 has introduced one change in rule sets:

• New character commands were added to the svr_features rule set (Section 19.1.1 ^[V8.13]).

More srv_features Return Values

The svr_features rule set (19.1.3^[3ed]) returns a $# followed by one or more of the characters defined in Table 19-1. Each character turns a feature on or off. If the character is lowercase, it turns the feature on. Uppercase turns the feature off. One character, the t, is special because it causes sendmail to temporarily fail the connection. Prior to V8.13, the characters listed in the table below (as documented in V8.13) were undocumented (and thus unsupported). They are now both documented and supported.

Table 19-1. Characters that set/clear server features

On	Off	Documented	Description
a	A	V8.12	Offer the AUTH SMTP extension
b	B	V8.13	Offer use of the SMTP VERB command
c	C	V8.12	“C” is the equivalent to AuthOptions=p; i.e., it doesn’t permit mechanisms susceptible ...