Re: smtpmail and gmx

[Jens Lechtenboerger <jens.lechtenboerger@fsfe.org>]

On 2018-12-11, at 17:02, Uwe Brauer wrote:

> Oops, according to the documentation it should be mail.gmx.de
> in thunderbird port 587 works, but 
> gnutls-cli --insecure -p 587 mail.gmx.de
>
> Does not work while 
>
> gnutls-cli --insecure -p 465 mail.gmx.de
>
> Works, 
>
> But       (setq smtpmail-auth-credentials '(("mail.gmx.de" 465 "user"
> nil)))
>
> Does not work.

Port 465 is SMTPS, while port 587 starts out with plaintext SMTP and
uses STARTTLS to switch to TLS.  You need to use --starttls with
gnutls-cli, probably also --crlf:
gnutls-cli --insecure --crlf --starttls -p 587 mail.gmx.de
Afterwards, you need to talk SMTP: Type “ehlo localhost”, then
“starttls”; press ctrl-d to enter TLS mode, which shows crypto
details.

I set smtpmail-smtp-server, smtpmail-smtp-service, and
smtpmail-smtp-user and use ~/.authinfo.gpg for passwords;
smtpmail-auth-credentials does not exist here.  Also, I have this
(where the first two entries are not used any longer):

;; smtpmail may use STARTTLS via gnutls, if supported.
;; Enforce it, give extra argument for certificate pinning.
(setq smtpmail-stream-type 'starttls
      starttls-extra-arguments '("--strict-tofu"))

Best wishes
Jens