$ telnet rage.so36.net 25
Trying 83.223.73.114...
Connected to rage.so36.net.
Escape character is '^]'.
220 rage.so36.net -> so36.NET e.V. <- ESMTP
helo localhost
250 rage.so36.net -> so36.NET e.V. <-
mail from: foo@so36.net
250 ok
rcpt to: bar@nadir.org
250 ok