Local mail delivery on Windows Server using IIS SMTP Service

iis_mail.rb

# config/environments/production.rb 
# Local mail delivery using IIS SMTP Service
require 'shim/mail_message' # fix line endings
config.action_mailer.delivery_method = :file
config.action_mailer.file_settings = { location: "#{ENV['SystemDrive']}/InetPub/MailRoot/Pickup" }

# lib/shim/mail_message.rb
# Patch Mail::Message to enforce proper line-endings for Windows IIS file-type delivery.
module Mail
  class Message
    alias :_encoded :encoded
    def encoded
      _encoded.encode(universal_newline: true)
    end 
  end 
end