first postfix on debian runs chrooted by default. unless you installed it from source.
you can check it main.cf values by issuing "postconf -d" command
now it depends what way you like to configure postfix main fails > main and master conf.
for example you can do its conf by webmin or by hand.
i suggest to start from
www.postfix.org reading documentation and links.
MAN postfix helps too.
if you want quick hint why it doesn't work or listen > tail -f /var/log/mail.log
postfix complains there.
don't be afraid, it is easier than you think.
wait:
i reread your post.
you said:
"Connected to localhost.localdomain.
Escape character is '^]'."
so you get answer, but what did you expect?
if your main.conf doesn't tell smtpd to say exactly something more about himself, it just said what you see.
now you must proceed to smtp conversation with introducing yourself with helo or ehlo command.
i thought you did "netsat -la" command and there wasn't smtp or 25 port listed.
mis-configured smtpd deamon will hang quickly after smtp session starts and you can see reason in mail.log.
