root@mail:~# telnet 200.83.2.212 25
Trying 200.83.2.212...
Connected to 200.83.2.212.
Escape character is '^]'.
220 fe1.vtr.cl ESMTP CommuniGate Pro 5.0.9
helo mail.kinetica.cl
250 fe1.vtr.cl is pleased to meet you
mail from:<mbarrera@kinetica.cl>
478 mbarrera@kinetica.cl reverse check protocol error
quit
221 fe1.vtr.cl CommuniGate Pro SMTP closing connection
Connection closed by foreign host.
root@mail:~#