What is the difference between config.action_mailer.smtp_settings and ActionMailer::Base.smtp_settings in Rails?

Question

I set up an Exchange compatible mail server in a RoR application. I used the following setup in development.rb:

config.action_mailer.smtp_settings = {
  :address              => 'mail.server.com',
  :port                 => 5870,
  :user_name            => 'username',
  :password             => 'password',
  :authentication       => :login
}

This setup does not work, I get Net::SMTPAuthenticationError: 504 Unrecognized authentication type.

However if I apply the exact same configuration in environment.rb, it works perfectly:

ActionMailer::Base.smtp_settings = {
  :address              => 'mail.server.com',
  :port                 => 5870,
  :user_name            => 'username',
  :password             => 'password',
  :authentication       => :login  
}

Why is this? Shouldn't config.action_mailer.smtp_settings set the same settings? Is this a bug? Does it have a reason?

I tried it with Gmail as told here, and it works, so smtp_settings does have effect on the mailer, but it seems to me like not all the options count/work.

Answer 1

config.action_mailer.smtp_settings forwards the settings to ActionMailer::Base.smtp_settings.

However, the main difference is that the former is an environment-specific setting while the second one is a global setting.

In other word, you should be sure to set config.action_mailer.smtp_settings in the proper environment file to apply the settings. If you want to use the settings in production, for example, add the assignment in the config/environments/production.rb file. Likewise, if you want the settings to be applied to the entire project, set them in config/application.rb.

Answer 2

I had similar problem, the config.action_mailer.smtp_settings did not work, but every configuration was proper.

Finally i figured out, that a Rails extension overrides the ActionMailer::Base settings in the initializer phase... So investigate all your code and all the 3rd party codes (!), extensions, modules, etc. there should be the problem!