[Disclaimer: sendmail is very complicated, and I lack some knowledge. The following solution might be even bad, although it works (tm). Please post comments if you know better ways, and I'll update the post]
I was looking for a quick n' simple SMTP solution for sending mails only. Requirements:
- A service that'll simply accept mails submitted locally and maintain a queue of mails-for-sending.
- It'll then send the mails by SMTP directly to the target servers (i.e. gmail.com).
- It should retry for a few days, if failed sending due to a local (dead connection) or remote problem.
- A bizarre one: it should be listening on a port other than 25, because another daemon uses it already. I know it's nonstandard and doesn't make sense, but should be possible..