diff --git a/cmdeploy/src/cmdeploy/postfix/main.cf.j2 b/cmdeploy/src/cmdeploy/postfix/main.cf.j2
index e5a02dd9..21c869ea 100644
--- a/cmdeploy/src/cmdeploy/postfix/main.cf.j2
+++ b/cmdeploy/src/cmdeploy/postfix/main.cf.j2
@@ -24,7 +24,22 @@ smtp_tls_security_level=may
 smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
 smtp_tls_policy_maps = socketmap:inet:127.0.0.1:8461:postfix
 smtpd_tls_protocols = >=TLSv1.2
-smtpd_tls_exclude_ciphers = ECDHE-RSA-RC4-SHA, RC4, aNULL, DES-CBC3-SHA, ECDHE-RSA-DES-CBC3-SHA, EDH-RSA-DES-CBC3-SHA
+
+# Disable anonymous cipher suites
+# and known insecure algorithms.
+#
+# Disabling anonymous ciphers
+# does not generally improve security
+# because clients that want to verify certificate
+# will not select them anyway,
+# but makes cipher suite list shorter and security scanners happy.
+# See <https://www.postfix.org/TLS_README.html> for discussion.
+#
+# Only ancient insecure ciphers should be disabled here
+# as MTA clients that do not support more secure cipher
+# likely do not support MTA-STS either and will
+# otherwise fall back to using plaintext connection.
+smtpd_tls_exclude_ciphers = aNULL, RC4, MD5, DES
 
 # Override client's preference order.
 # <https://www.postfix.org/postconf.5.html#tls_preempt_cipherlist>