$ telnet sendmail.org 25
Trying 209.246.26.22...
Connected to sendmail.org.
Escape character is '^]'.
220 services.sendmail.org ESMTP Sendmail 8.14.0.Alpha1/8.14.0.Alpha1; Mon, 25 Jun 2007 22:09:42 -0700 (PDT)
HELO localhost
250 services.sendmail.org Hello foo.bar.com [199.199.199.199], pleased to meet you
QUIT
221 2.0.0 services.sendmail.org closing connection
Connection closed by foreign host.