The
tls_server rule set is called at the start of any
connection in which the local sendmail would
normally issue the STARTTLS SMTP command. The
tls_client rule set is called at the start of any
inbound connection in which the STARTTLS SMTP command was offered.
Both rule sets look up information in the access
database. (See Section 10.10.8.2 for a full description of
this process.)
The tls_server rule set prefixes its lookups with
a literal TLS_Srv: expression, and the
tls_client rule set prefixes its lookups with a
literal TLS_Clt: expression. Among the possible
returned values from the lookup can be two special keywords:
TLS_Srv:hostA.domain VERIFY
TLS_Clt:hostB.domain ENCR:bits
These two special keywords (VERIFY and ENCR) are not defined inside
sendmail. Instead, they are defined as values
given to the class $={tls}.
The $={tls} is properly defined in your default
configuration file and should never need adjustment.
