echo EHLO <myhost> | nc <myserver> 25Replace <myserver> with the name of your server. <myhost> should be your host name but anything will do. Notice its EHLO not HELO.
Programming Tips - SMTP: See what extensions an SMTP server supports
Date: 2013apr22
Protocol: SMTP
OS: Linux
Keywords: postfix, sendmail, qmail
Q. SMTP: See what extensions an SMTP server supports
A. Connect and issue the EHLO command. The names of
the extensions will be listed on multiple lines.
This bash command line will do it: