Rule Sets for Running SMTP With TLS (System Administration Guide: Network Services)

System Administration Guide: Network Services

The following table describes rule sets that determine whether an SMTP connection that uses TLS should be accepted, continued, or refused.

Table 14–15 Rule Sets for Running SMTP With TLS


Rule Set	Description
`tls_server`	Acting as a client, `sendmail` uses this rule set to determine whether the server is currently supported by TLS.
`tls_client`	Acting as a server, `sendmail` uses this rule set to determine whether the client is currently supported by TLS.
`tls_rcpt`	This rule set requires verification of the recipient's MTA. This recipient restriction makes attacks such as DNS spoofing impossible.
`TLS_connection`	This rule set checks the requirement that is specified by the RHS of the access map against the actual parameters of the current TLS connection.
`try_tls`	`sendmail` uses this rule set to determine the feasibility of using `STARTTLS` when connecting to another MTA. If the MTA cannot properly implement `STARTTLS`, then `STARTTLS` is not used.