Address feedback

- Set enum 0 as UNSPECIFIED
- Update enum names

api/proto/teleport/legacy/types/types.proto

@@ -6620,19 +6620,22 @@ message SMTPSpec {
 // SMTPStartTLSPolicy defines the start TLS policy used to communicate with the
 // SMTP service.
 enum SMTPStartTLSPolicy {
-  // SMTP_MANDATORY_START_TLS means that SMTP transactions must be encrypted.
-  // SMTP transactions are aborted unless STARTTLS is supported by the
-  // SMTP server. Recommended for all modern SMTP servers.
-  SMTP_MANDATORY_START_TLS = 0;
-
-  // SMTP_OPPORTUNISTIC_START_TLS means that SMTP transactions are encrypted if
-  // STARTTLS is supported by the SMTP server. Otherwise, messages are
-  // sent in the clear.
-  SMTP_OPPORTUNISTIC_START_TLS = 1;
-
-  // SMTP_NO_START_TLS means encryption is disabled and messages are sent in the
-  // clear.
-  SMTP_NO_START_TLS = 2;
+  // SMTP_START_TLS_POLICY_UNSPECIFIED is the default zero value.
+  SMTP_START_TLS_POLICY_UNSPECIFIED = 0;
+
+  // SMTP_START_TLS_POLICY_MANDATORY means that SMTP transactions must be
+  // encrypted. SMTP transactions are aborted unless STARTTLS is supported by
+  // the SMTP server. Recommended for all modern SMTP servers.
+  SMTP_START_TLS_POLICY_MANDATORY = 1;
+
+  // SMTP_START_TLS_POLICY_OPPORTUNISTIC means that SMTP transactions are
+  // encrypted if STARTTLS is supported by the SMTP server. Otherwise, messages
+  // are sent in the clear.
+  SMTP_START_TLS_POLICY_OPPORTUNISTIC = 2;
+
+  // SMTP_START_TLS_POLICY_DISABLED means encryption is disabled and messages
+  // are sent in the clear.
+  SMTP_START_TLS_POLICY_DISABLED = 3;
 }
 
 message PluginBootstrapCredentialsV1 {

api/types/plugin.go

@@ -802,6 +802,9 @@ func (c *SMTPSpec) CheckAndSetDefaults() error {
 	if c.Port == 0 {
 		return trace.BadParameter("port must be set")
 	}
+	if c.StartTlsPolicy == SMTPStartTLSPolicy_SMTP_START_TLS_POLICY_UNSPECIFIED {
+		c.StartTlsPolicy = SMTPStartTLSPolicy_SMTP_START_TLS_POLICY_MANDATORY
+	}
 	return nil
 }
 

api/types/plugin_test.go

@@ -1298,7 +1298,7 @@ func TestPluginEmailSettings(t *testing.T) {
 					SmtpSpec: &SMTPSpec{
 						Host:           "smtp.example.com",
 						Port:           587,
-						StartTlsPolicy: SMTPStartTLSPolicy_SMTP_OPPORTUNISTIC_START_TLS,
+						StartTlsPolicy: SMTPStartTLSPolicy_SMTP_START_TLS_POLICY_OPPORTUNISTIC,
 					},
 				}
 			},