diff --git a/config/discourse_defaults.conf b/config/discourse_defaults.conf
index a383e71f96b..c7662b9ee53 100644
--- a/config/discourse_defaults.conf
+++ b/config/discourse_defaults.conf
@@ -56,6 +56,9 @@ smtp_user_name =
 # password for smtp server
 smtp_password =
 
+# smtp authentication mechanism
+smtp_authentication = plain
+
 # enable TLS encryption for smtp connections
 smtp_enable_start_tls = true
 
diff --git a/config/environments/production.rb b/config/environments/production.rb
index 017bd7b0970..c63b5d05c87 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -39,7 +39,7 @@ Discourse::Application.configure do
       domain:               GlobalSetting.smtp_domain,
       user_name:            GlobalSetting.smtp_user_name,
       password:             GlobalSetting.smtp_password,
-      authentication:       'plain',
+      authentication:       GlobalSetting.smtp_authentication,
       enable_starttls_auto: GlobalSetting.smtp_enable_start_tls
     }