telnet 192.168.0.2 25 # Comments Trying 192.168.0.2... Connected to 192.168.0.2 (192.168.0.2). Escape character is '^]'. 220 mail.example.com ESMTP Postfix # <-smtp_client_restrictions HELO mail.example.com # <-smtp_helo_restrictions 250 mail.example.com # MAIL FROM:<ned@example.com> # <-smtp_sender_restrictions 250 2.1.0 Ok # RCPT TO:<ned@example.com> # <-smtp_recipient_restrictions 250 2.1.5 Ok # DATA # <-smtp_data_restrictions 354 End data with <CR><LF>.<CR><LF> # To:<ned@example.com> # <-header_checks From:<ned@example.com> # Subject:SMTP Test # This is a test message # <-body_checks . # 250 2.0.0 Ok: queued as 301AE20034 QUIT 221 2.0.0 Bye Connection closed by foreign host.