$ telnet 213.222.138.152 25
Trying 213.222.138.152...
Connected to 213.222.138.152.
Escape character is '^]'.
220 dreamnetwork.hu ESMTP Postfix (2.4.6)
HELO foo.hu
250 dreamnetwork.hu
MAIL FROM: foo@bar.baz
250 2.1.0 Ok
RCPT TO: postmaster@lillevenn.hu
554 5.7.1 <postmaster@lillevenn.hu>: Relay access denied
QUIT
221 2.0.0 Bye
Connection closed by foreign host.