I'm using postfix on ubuntu 12.04 server, with help from https://help.ubuntu.com/community/Postfix
after setting up sasl as above guide, I tried sendmail - and sendmail just hangs.
here's what I've done:
# cat mail.mail
To: <myid>@gmail.com
Subject: test mail
From: root@<myserver.com>
a test mail
# sendmail -vt mail.mail
(a blank line displayed forever and i have to Ctrl+C out of it)
though I can send mail via telnet.
#telnet localhost 25
EHLO <myserver.com>
MAIL FROM: root@<myserver.com>
RCPT TO: <myid>@gmail.com
DATA
test mail
.
(mail sent to <myid>@gmail.com, thrown directly to junks though)