gnutls
exim -DSERVER=server -bd -oX PORT_D
****
-client-ssl 127.0.0.1 PORT_D
+client-gnutls 127.0.0.1 PORT_D
??? 220
ehlo foobar
??? 250-myhost
auth plain AHVzZXJ4AHNlY3JldA==
??? 503
****
-client-ssl 127.0.0.1 PORT_D
+client-gnutls 127.0.0.1 PORT_D
??? 220
ehlo foobar
??? 250-myhost