Test the sendmail installation from the command line. Make sure you don’t have any permission issues. There is no configuration required for sendmail. Rails will automagically send mails.
Test email addresses with different domains. Is the mail server running on the local server where your Rails app is deployed? Can you connect email client such as Apple Mail using the SMTP server settings and send email?
If the mail server is configured properly, you should define the mail server settings in the appropriate environment config file, ex - for production , define it in production.rb. In Rails 2.0 the syntax has changed:
ActionMailer::Base.smtp_settings = define_your_server_settings
Use email client such as ms outlook, eudora etc and use the parameters
u r using in the rails app to connect to the email server. Check if u
can send any email.