設定
$ diff --git a/postfix/main.cf b/postfix/main.cf
index f86f66b..2553d51 100644
--- a/postfix/main.cf
+++ b/postfix/main.cf
@@ -25,6 +25,10 @@ smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

+smtp_tls_CAfile = /etc/letsencrypt/live/kagolug.org/cert.pem
+smtp_tls_security_level = may
+smtp_tls_loglevel = 1
+
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.