submission_host auth

[k v]

Thanks for the reply, postfix + dovecot sasl configured and working properly. My question is about "adding dovecot authentication when sending emails via submission_host".

Let's say we have dovecot + sieve plugin container.
Dovecot configured to use remote SMTP submission host to send messages:
submission_host = postfix.example.com:587

User foo at example.com has the following sieve script:
require ["fileinto", "copy", "vacation", "date", "relational"] ;
redirect :copy "bar at example.com";
keep;

baz at example.com sending email to foo at example.com

dovecot lmtp log:
lmtp(foo at example.com)<7670><QTsrNZjdxmP2HQAAaVGrHw>: Info: sieve: msgid=<63fce409f26b1a67785a475a00034a05 at mail.example.com>: redirect action: failed to redirect message to <bar at example.com>: smtp(postfix.example.com:587): RCPT TO failed: 554 5.7.1 <bar at example.com>: Recipient address rejected: Access denied (permanent failure)
lmtp(foo at example.com)<7670><QTsrNZjdxmP2HQAAaVGrHw>: Info: sieve: msgid=<63fce409f26b1a67785a475a00034a05 at mail.example.com>: stored mail into mailbox 'INBOX'
lmtp(foo at example.com)<7670><QTsrNZjdxmP2HQAAaVGrHw>: Info: sieve: Execution of script /var/dovecot/example.com/foo/foo.sieve failed, but implicit keep was successful (user logfile /var/dovecot/example.com/foo/foo.sieve.log may reveal additional details)

sieve.log
error: msgid=<63fce409f26b1a67785a475a00034a05 at mail.example.com>: redirect action: failed to redirect message to <bar at example.com>: smtp(postfix.example.com:587): RCPT TO failed: 554 5.7.1 <bar at example.com>: Recipient address rejected: Access denied (permanent failure).

postfix log:
NOQUEUE: reject: RCPT from unknown[10.0.1.4]: 554 5.7.1 <bar at example.com>: Recipient address rejected: Access denied; from=<baz at example.com> to=<bar at example.com>

redirect :copy action failed, its expected behavior, dovecot do not auth when sending email via submisson_host.
If there is setting like
submission_host_master_user = master at example.com
submission_host_master_password = masterpass
to do authentication as master user in postfix who can send email as any user...



________________________________
От: dovecot <dovecot-bounces at dovecot.org> от имени dovecot at ptld.com <dovecot at ptld.com>
Отправлено: 17 января 2023 г. 18:25
Кому: dovecot at dovecot.org <dovecot at dovecot.org>
Тема: Re: submission_host auth

> When using dovecot container with sieve plugin there is no sendmail to use for sending email for sieve redirect action for example. We can use submission_host instead https://doc.dovecot.org/settings/core/#core_setting-submission_host but there is no way to specify credentials for auth in remote MTA. Submission_relay_* settings e.g. submission_relay_master_user relate to dovecot submission service. Using something like permit_mynetworks in remote MTA is not acceptable for security reasons.
>
> Is it possible to add authorization in the remote MTA using submission_host?


You start the auth service in dovecot, then tell the MTA to use it.
For example, if you use postfix this explains how:

   https://doc.dovecot.org/configuration_manual/howto/postfix_and_dovecot_sasl/
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