title: Mail Server with javax.mail and CentOS
body: <p>I have a Java Program that was installed on an old Ubuntu machine and sent mail using javax.mail. However, that machine went down and I am now running the same Java app in a new CentOS machine.</p>
  
  <p>However, I get an error "MessagingException: 501 Syntax: HELO hostname" when trying to send an email using mail.smtp.host = 127.0.0.1.</p>
  
  <p>My guess is that the mailserver is not yet activated in this CentOS.</p>
  
  <p>How would I go about configuring a mail server that javax.mail can use?</p>
  
  <p>Thank you</p>