220 myhost.test.ex ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000
250 OK
550-Verification failed for <unknown@x.x.x.x>
550-Called:   127.0.0.1
550-Sent:     RCPT TO:<unknown@x.x.x.x>
550-Response: 550 unrouteable address
550 Sender verify failed
221 myhost.test.ex closing connection

******** SERVER ********
Listening on port 1224 ... 
Connection request from [127.0.0.1]
220 Welcome
HELO myhost.test.ex
250 Hi
MAIL FROM:<>
250 OK
RCPT TO:<unknown@x.x.x.x>
550 unrouteable address
QUIT
221 Bye
End of script