Trying 192.168.1.25...
Connected to ghz.
Escape character is '^]'.
220 localhost ESMTP Sendmail 8.2.0/8.2.0; Sat, 12 Mar 1994 01:41:48 GMT
HELO foo.bar
250 Hello foo.bar, nice to meet you.
VRFY bob
252 Cannot VRFY user; try RCPT to attempt delivery (or try finger)
VRFY bob@example.com
251 User not local; will forward to bob@example.com
EXPN alice
250 alice
EXPN carol@example.com
250 carol@example.com
MAIL FROM: spammer
553 spammer... Domain name required for sender address
MAIL FROM: <spammer@example.com>
250 <spammer@example.com>... Sender ok
RCPT TO: <alice>

553 <alice>... User unknown
RCPT TO: <alice@yahoo>
553 <alice@yahoo>... User unknown
RCPT TO: <alice@yahoo.example.com>
250 <alice@yahoo.example.com>... Recipient ok
RCPT TO: <bob@example.com>
250 <bob@example.com>... Recipient ok
RCPT TO: carol
553 carol... User unknown
RCPT TO: carol@example.com
250 carol@example.com... Recipient ok
DATA
354 Enter mail, end with "." on a line by itself
Subject: A special opt-in message for you!

This is not spam. Really. You opted in ten years ago.
.
250 Message accepted for delivery
RSET
250 OK
MAIL FROM: friend@public.com
250 friend@public.com... Sender ok
RCPT TO: customers@example.com
250 customers@example.com... Recipient ok
MAIL FROM: friend@public.com
503 Nested MAIL command
DATA
354 Enter mail, end with "." on a line by itself
Subject: Friend, Mortgage Rates are LOWEST EVER

You can enlarge your penis and have a low mortgage too!

.
250 Message accepted for delivery
QUIT
221 localhost closing connection.
Connection closed by foreign host.