Receiving email via Postfix and qmail has previously been described on this forum ( http://news.ycombinator.com/item?id=186879 ). To send email, pipe data to /usr/lib/sendmail or suchlike. Postfix, qmail and other MTAs typically install a wrapper at /usr/lib/sendmail
However, if you're hosting on ADSL, the IP address of your mail server is probably blacklisted, so you may have to configure your MTA to forward messages to your ISP's MTA. I found this easiest to configure in Sendmail, which can be configured to co-exist with other MTAs.
However, if you're hosting on ADSL, the IP address of your mail server is probably blacklisted, so you may have to configure your MTA to forward messages to your ISP's MTA. I found this easiest to configure in Sendmail, which can be configured to co-exist with other MTAs.