On Wed, Nov 17, 2021 at 07:53:47PM +0100, Daniel Tameling wrote:
> On Tue, Nov 16, 2021 at 04:36:43PM -0500, Andrew D. Arenson wrote:
> > I receive email using IMAP via a davmail process that in turn interacts
> > with Indiana University's Office 365 Exchange instance.
>
> If you use davmail, you don't have to use TLS for sendmail: "SSL is not
> necessary when DavMail is used in workstation mode, as communication between
> clients and DavMail remain local. However, in server (shared) mode e.g. with
> a smartphone connecting to DavMail over the internet, you should make sure
> encryption is enabled." (http://davmail.sourceforge.net/sslsetup.html)
>
> If you want to use TLS, the link contains also information on how to set that
> up.
>
> The TLS connection between davmail and the Exchange server is taken care of
> by davmail itself and it seems to be working in your setup as you can read
> emails through davmail.
>
> Personally I use msmtp instead of sendmail. I'm currently not at my work
> notebook but a quick google search turned up this with a .msmtprc that looks
> reasonable: https://cstan.io/?p=8790&lang=en
>
> It shouldn't be too much work to set that up in case you want to try it in
> order to be sure your setup is otherwise correct.
Thanks. Learning the details of what the email client is doing versus
the MTA, and distinguishing various online information related to TLS and email
by whether the TLS is being used for receiving email, sending email, encrypting
email, or signing email has been a challenge! I appreciate the idea, as I
understand it, that I could send the email via my davmail gateway w/ Exchange.
Looks like I have three different ways to send email:
* via local MTA (mutt's default, I think)
* via university mail relay (either by congifuring the local MTA to use
it, or possibly configuring mutt to use it)
* via davmail/Exchange (by configuring mutt, I think)
My next step will likely be to replace sendmail with postfix on my
workstation, see if that solves the problem immediately, and, if not, leverage
work I've done in the past to configure postfix to use our university's mail
relay and see if that solves the problem. If those both fail, perhaps I'll look
into configuring mutt to use the university mail relay or configure mutt to use
the davmail gateway to Exchange.
Andy
--
Andrew D. Arenson (he/him) H 317.964.0493
arenson (at) spatzel.net C 317.679.4669
