--- conf/main.cf.orig	2022-03-12 22:37:09 UTC
+++ conf/main.cf
@@ -681,4 +681,7 @@ sample_directory = /etc/postfix
 # readme_directory: The location of the Postfix README files.
 #
 readme_directory = no
-inet_protocols = ipv4
+inet_protocols = all
+
+# smtp CA path (default to system-wide location)
+smtp_tls_CApath = /etc/ssl/certs