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<p>Yes Dovecot will proxy the connection to the real MTA. My
question is why authentication is <i>always</i> required on
Dovecot when submission is used, as MTAs usually have an option to
allow non-authenticated relaying. <br>
</p>
<div class="moz-cite-prefix">On 7/28/21 10:19 AM, justina colmena
~biz wrote:<br>
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<blockquote type="cite"
cite="mid:164FEC77-429B-4D38-B5C4-58442C5C5556@colmena.biz">
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I am quite curious about the circumstances of this question. I was
not aware that Dovecot actually offered mail submission service.
If Dovecot does offer such a service, then it will have to relay
the submitted mail to the real MTA, which is very likely not
Dovecot. At the moment I have Postfix set up as MTA for that
purpose —<br>
<br>
Relaying on port 25 is usually quick and easy to whitelist for
certain permitted hosts, but otherwise port 587, optionally with
STARTTLS, and/or port 465 with SSL/TLS is generally set up for
user authenticated mail submissions.<br>
<br>
See also:<br>
<a
href="https://www.mailgun.com/blog/which-smtp-port-understanding-ports-25-465-587/"
moz-do-not-send="true">https://www.mailgun.com/blog/which-smtp-port-understanding-ports-25-465-587/</a><br>
<br>
<br>
<br>
<div class="gmail_quote">On July 28, 2021 6:10:28 AM AKDT, Dan
Conway <a class="moz-txt-link-rfc2396E" href="mailto:darkc0de@archnix6.net"><darkc0de@archnix6.net></a> wrote:
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<pre class="k9mail">Hello,
Is it possible to disable the requirement for authentication on the
submission service? I'm trying to require authentication for all, except
for a handful of IP addresses.
Thank you.
ehlo test.com
250-aaa
250-AUTH PLAIN LOGIN
250-BURL imap
250-CHUNKING
250-DSN
250-ENHANCEDSTATUSCODES
250-SIZE
250 PIPELINING
MAIL FROM:<a class="moz-txt-link-rfc2396E" href="mailto:test@test.com"><test@test.com></a>
530 5.7.0 Authentication required.
</pre>
</blockquote>
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<br>
-- <br>
Sent from my Android device with K-9 Mail. Please excuse my
brevity.
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