Using the DragonFly Mail Agent as default MTA in Debian Jessie
As of 13.June.2013 69 packages depend on mail-transport-agent (including bsd-mailx priority standard) and 40 other packages in testing/jessie recommend the virtual package mail-transport-agent (including cron, which is priority required and apt-listchanges, at, mutt and procmail, which are priority standard).
In many cases the functionality required is little more than sending a local mail to root or the corresponding user (cron, apt-listchanges, at) or forwarding mail to the outside (bsd-mailx, mutt, procmail). It is expected that for any "serious" use (i.e. MX or similar) the system administrator should be capable to install and configure a full featured MTA like exim, postfix, etc.
Based on this following features should be sufficient to fullfil these necessities:
- local delivery
- forwarding to a smarthost
- defering if immediate delivery is not possible
Any other features, like listening to port 25 (even if only on localhost) are just increasing complexity and vulnerability of the system and the MTA itself.
As of version 0.0.2010.06.17-14.1 DMA is capable of all of the above, without running as a daemon (it relies on cron to flush the queue, see README.Debian for more details).
install size only 224 (compared to 1040 for exim4-daemon-light + 1672 for exim4-base + 1272 for exim4-config, or 3196 for postfix)
no daemon (relies on cron to flush the queue)
- upstream willing to implement additional features required by Debian
DMA maintenance: 671364
- only one smarthost possible: using more than one smarthost is considered a complex setup and should be implemented using the admin's prefered MTA
local delivery to /var/mail/ only: it would be nice for dma to also be able to use an MDA for local delivery (712137), but this is probably not a show stopper
- lurking bugs: since DMA is not widely used it probably has undiscovered bugs. More testing is highly recommended.
- credentials are stored in a plain text file: this is the same for all other MTAs used in such simple setups.
nobody is reading local mail: DMA supports /etc/aliases and could be used to forward all mail to an external e-mail address if so desired. While e-mail is not necessarily the best notification system there is still no better replacement available.