add more tls settings

Author: NickOvt

lib/smtp-interface.js

@@ -319,7 +319,11 @@ class SMTPInterface {
                     'closeTimeout',
                     'secured',
                     'banner',
-                    'ciphers'
+                    'ciphers',
+                    'minVersion',
+                    'dhparam',
+                    'secureProtocol',
+                    'secureOptions'
                 ]) {
                     if (this.options[key]) {
                         serverConfig[key] = this.options[key];