title: Mikrotik block all ports except mail server
body: <p>I Have a Mikrotik. our Exchange mail server IP is 192.168.200.3. I wanted to block all inbound and outbound traffic by blocking all port except mail port in this ip.</p>
  
  <p>I wrote these filter in firewall:</p>
  
  <pre>
  add chain=forward Src. Address= 192.168.200.3 protocol=tcp Src-port=!25,443,465,587,2525 Out. Interface=ppoe(internet Interface) action=drop
  add chain=forward Dst. Address= 192.168.200.3 protocol=tcp Dst-port=!25,443,465,587,2525,717 In. Interface=ppoe(internet Interface) action=drop
  </pre>
  
  <p>After apply these filter, I can receive mail from outside of network but I couldnt sent any mail. when I look at exchange server toolbox Queue there is a winsocket error 10051 on port 25.</p>
  
  <p>What should I do to fix this?</p>