Re: need for open-minded help with popularity-contest with systemd timer

On Sun, 2026-07-26 at 08:56 -0700, alimiracle wrote:
> The `sendmail` interface has served Unix systems extremely well
> fordecades, but it was designed around assumptions that modern
> service managers intentionally no longer guarantee. Trying to
> preserve those assumptions inside increasingly hardened systemd units
> feels liketreating the symptom rather than the underlying issue.

> An explicit mail submission service with a well-defined API,
> whetherover D-Bus or another IPC mechanism, would provide a cleaner
> contract between applications and the local MTA. It would also make
> authorization, auditing, and sandboxing much more predictable
> thanrelying on `setuid`/`setgid` behavior.

You seem to assume the “sendmail interface” requires a local MTA (it
doesn’t).

> At the same time, I hope any new interface remains MTA-agnostic
> andsimple to implement. One of the strengths of the traditional
> `sendmail` interface is that applications do not need to know whether
> the underlying MTA is Exim, Postfix, OpenSMTPD, or something else. It
> would be great if we could preserve that portability while
> modernizing the implementation.

I don’t think the “sendmail interface” is the problem here, rather than
many current implementations of it.  Maybe the “sendmail interface”
implementations provided by Exim/Postfix/etc. need to implement
alternative ways to hand over mails on hardened systems though.  Or an
independent “sendmail interface” implementation (possibly provided by
systemd?) needs to act as a bridge.

That said, there might be a good reason to define a more modern API
than the “sendmail interface”, but that’s a separate issue (it would
not solve issues with existing software using the interface).


-- 
Jan Claeys

(please don't CC me when replying to the list)