tianon/exim4 repository overview

⁠NOTE

I've personally stopped using this image! These days I just use msmtp⁠ instead, which gives my application direct feedback on the success/failure instead of filling up a "frozen" queue in exim4 that I then also have to manage. At some point, I'll probably stop maintaining this image entirely.

⁠How To Use

You will want to set a reasonable hostname of some kind (--hostname), since that's symlinked to /etc/mailname inside the image and used for outgoing mail metadata.

⁠sSMTP

If you want to use this with another container that has sSMTP or similar installed, here's a configuration you can adapt: (assuming your second container uses something like --link some-exim4:smtp)

Mailhub=smtp
FromLineOverride=Yes

Then sendmail in your linked container should work as expected. You can also skip FromLineOverride in the second container if you want, but the alternative is sSMTP being weird about hostnames and forcing you into a box.

⁠Gmail / "smarthost" (external SMTP)

If you'd rather not relay mail directly (which is a smart thing to not want to do generally), you can trivially configure this container to relay via a Gmail account instead! Just add -e [email protected] -e GMAIL_PASSWORD=yourpasswordhere and the entrypoint will automatically preconfigure to relay via the Gmail account specified!

Alternatively, you can use this container as a proxy for another SMTP server via -e EXIM4_SMARTHOST='smtp.yourdomain.com::587' -e EXIM4_SMARTHOST_USER='[email protected]' -e EXIM4_SMARTHOST_PASSWORD='yourpasswordhere' (in fact, GMAIL_* are shorthand for EXIM4_SMARTHOST='smtp.gmail.com::587' 😄).