title: Exchange drop support for SMTP?
body: <p>I want to send email with Exchange by using telnet to port 25. Until two week ago I was able to, but now a "security fix" from Microsoft has removed this possibility.</p>
  
  <p>When I try, I get this message:</p>
  
  <p>421 4.3.2 Service not available, closing transmission channel</p>
  
  <p>What can I do?</p>