So far I’ve been using Nullmailer only to relay mail from LAN machines to SMTP servers that accept anything from the internal network, a very easy method to forward system messages from various internal boxes without the need to administrate a full-blown MTA.
For my home box however the relay server is external and so it needs both STARTTLS and SMTP-AUTH on the submission port to accept mail from my dynamic IP. Until now nullmailer did not support STARTTLS or at least I could not find any documentation on it.
Getting things working
With nullmailer 1.10 this has finally changed, the documentation that one usually looks at (homepage, manpage,
/usr/share/doc/nullmailer/) however is still lacking so I decided to write down how I got things working.
The key to enable STARTTLS for a remote server in nullmailer is simply to add
--starttls to remote configuration which can usually be found in
And that’s actually all there is to it :)
Why does this work
After some more digging it turned out that the
--option parts in the above configuration file are simply forwarded to
/usr/lib/nullmailer/smtp which is the binary that handles the actual SMTP dialog. And voila, this binary even has a
--help switch which will present you the following:
So after a few minutes of wandering around my box, looking at files and package contents I could finally find out how to replace my local Postfix install (a bit overkill for a home machine) with the more lightweight Nullmailer.