diff --git a/src/smtp.c b/src/smtp.c
index 5dd801a..3565b5c 100644
--- a/src/smtp.c
+++ b/src/smtp.c
@@ -377,7 +377,11 @@ int _smtp_session_internal_connect_cont (SMTPSession *session) {
 		return SMTP_ERROR;
 	}
 	
-	/* FIXME: Revisar el valor de optval */
+	if (optval != 0) {
+		smtp_session_close_and_clean (session);
+
+		return SMTP_ERROR;
+	}
 	
 	/* Pasamos a la lectura del banner */
 	session->internal = SMTP_INTERNAL_READ;