telnet localhost 25
Connected to localhost.
Escape character is '^]'.
220 hostname.domain.tld ESMTP Postfix (Debian/GNU)
EHLO localhost
250-hostname.domain.tld
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
MAIL FROM: me@myserver.net
25...