title: Posfix - deny sender emails containing specific text in username
body: <p>Postfix, Debian. I'm receiving spam and I'm not sure how can block it, because spammers uses different mail address everytime. </p>
  
  <p>For example:
  mike.newsletter30@gmail.com
  mike.sfsd4f564s6df45ds@gmail.com
  mike.newsletter30u@gmail.com</p>
  
  <p>etc.</p>
  
  <p>I have setup sender access file, so I can block mails from specific servers like this:</p>
  
  <p>mike.newsletter30u@gmail.com REJECT</p>
  
  <p>But it's not enough. I need to setup more specific rule, for example all senders containing 'mike.' should be blocked in this case.</p>
  
  <p>Unfortunatelly, rule like this:
  mike. REJECT </p>
  
  <p>doesn't work. I've searched google and postfix docs I still can't figure out how to do this. Is this even possible?</p>
  
  <p>Do you have any ideas?</p>