I've set up a couple SMTP gateways using the instructions on http://qmailrocks.org.
I did NOT install vpopmail or the associated tools, as these servers are used for smtp only & are not hosting any mailboxes. I'm getting the following error when mail is sent to ONE domain thru these servers: "TLS found no client cert in control/clientcert.pem I'm not going to try again; this message has been in the queue too long." Here is an ls of /var/qmail/control:
