Thought I would share this useful piece of information.

To configure ActionMailer without SMTP Authentication (for example a server that might be in your postfix mynetworks list), all you need to do is configure ActionMailer as follows. The configuration goes in config/environment.rb :

ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.server_settings = { :address => “10.1.2.25”, :port => 25, :domain = “mydomain”
}