Trying 192.0.2.3... Connected to 192.0.2.3. Escape character is '^]'. 220 mx.example.net; ESMTP Mon, 13 Apr 2009 00:09:58 +0200 (CEST) EHLO example.org 250-mx.example.net Hello [192.0.2.137], pleased to meet you 250-ENHANCEDSTATUSCODES 250 HELP MAIL FROM: 250 2.1.0 ... Sender ok RCPT TO: 250 2.1.5 ... Recipient ok RCPT TO: 550 5.1.1 ... User unknown QUIT 221 2.0.0 mx.example.net closing connection