Dovecot Submission Proxy Auth

[Gerald Galster]

Hi Jacky,

in postfix/main.cf you typically set something like

smtpd_sasl_auth_enable=yes
smtpd_sasl_type=cyrus
smtpd_sasl_exceptions_networks=$mynetworks
smtpd_sasl_security_options=noanonymous
smtpd_sasl_authenticated_header=yes
broken_sasl_auth_clients=yes
smtpd_recipient_restrictions=permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination

smtpd_recipient_restrictions might already exist in main.cf and in that case has to be extended

postfix can verify login/passwords via sasl but it does not store these credentials, so you need to install saslauthd and add user/pass there or use a dovecot instance that already authenticates users for pop/imap.

http://www.postfix.org/SASL_README.html
https://wiki.dovecot.org/HowTo/PostfixAndDovecotSASL

Best regards
Gerald

> Am 09.01.2019 um 10:15 schrieb Jacky <jacky at jesstech.com>:
> 
> Hi,
> 
> Anyone know how to enable this SMTP AUTH feature with Postfix?
> 
> Regards,
> 
> Jacky
> 
> 
> On 7/4/2018 3:40 AM, Paul Hecker wrote:
>> Hi,
>> 
>>> On 6. Apr 2018, at 18:58, Odhiambo Washington <odhiambo at gmail.com> wrote:
>>> 
>>> Hi Paul,
>>> 
>>> Care to share your config (even OFFLIST) that has successfully integrated Dovecot Submission service with Exim??
>> here the steps I have done to integrate Dovecot submission in Exim:
>> 
>> - Create and set the acl_smtp_mailauth ACL:
>> 
>> acl_smtp_mailauth = acl_check_mailauth
>> 
>> acl_check_mailauth:
>>   accept
>>     hosts          = <; 127.0.0.1 ; ::1
>>     condition      = ${if eq{$interface_port}{10025}}
>>     log_message    = Will accept MAIL AUTH parameter for $authenticated_sender
>>        deny
>> 
>> 
>> - add a deny fo all connections to 10025 without MAIL AUTH parameter in acl_smtp_mail ACL:
>> 
>>   deny
>>     condition      = ${if eq{$interface_port}{10025}}
>>     condition      = ${if eq{$authenticated_sender}{}}
>>     message        = All connections on port $interface_port need MAIL AUTH sender
>> 
>> - in Dovecot, add the following submission parameters
>> 
>> submission_relay_port = 10025
>> submission_relay_ssl = starttls
>> submission_relay_ssl_verify = no
>> 
>> All the remaining parts of the Dovecot config is the default for submission protocol/service, copied either from the sources (default config) or from here:
>> 
>> https://wiki.dovecot.org/Submission
>> 
>> Feel free is you have any further questions.
>> 
>> Regards,
>> Paul
>> 
>> 
>>> I use Exim+Dovecot (Exim4U) and wouldn't mind exploring this.
>>> 
>>> Thanks in advance.
>>> 
>>> 
>>> On 6 April 2018 at 19:15, Paul Hecker <paul at iwascoding.com> wrote:
>>> Hi,
>>> 
>>> Thanks you very much. This did the trick!
>>> 
>>>> On 6. Apr 2018, at 15:56, Stephan Bosch <stephan at rename-it.nl> wrote:
>>>> 
>>>> 
>>>> 
>>>> Op 6-4-2018 om 13:52 schreef Paul Hecker:
>>>>> Hi,
>>>>> 
>>>>> Dovecot 2.3.1 (8e2f634). Could not get Dovecot to forward the (plain) authentication to the SMTP server using submission. Reason why I need it is sender spoofing (do not want my employees to send messages in behalf of me).
>>>>> 
>>>>> In exim I can disable sender spoofing with the authenticated user. When sending through dovecot, exim either does not accept the email (need auth) or relay every sender address (because relaying from localhost).
>>>>> 
>>>>> Am I missing a setting or do I need any additional field in the (MySQL) user_query/password_query to forward the password?
>>>>> 
>>>>> You can find my config here:
>>>>> 
>>>>> https://gist.github.com/lluuaapp/7daddf761131da47237b0f45e6bab5a8
>>>> That would be possible using the following SMTP AUTH feature:
>>>> 
>>>> https://tools.ietf.org/html/rfc4954#section-5
>>>> 
>>>> Which is apparently supported by Exim: https://www.exim.org/exim-html-current/doc/html/spec_html/ch-smtp_authentication.html#SECTauthparamail
>>>> This requires explicit configuration, so it will not work out of the box.
>>> Here is what I did:
>>> 
>>> I had to add the acl_smtp_mailauth to only allow this on a certain port. Then I had to duplicate my code for sender spoofing for authenticated users and change the $authenticated_id -> $authenticated_sender.
>>> 
>>> Besides that, I must use TLS (in my case STARTTLS) so that Dovecot actually sends the MAIL AUTH parameter.
>>> 
>>>> The Dovecot Submission service should support this too. It sends an AUTH parameter with the MAIL command (currently only then the username is a valid SMTP address). However, I must say, I haven't tested this recently.
>>> I can confirm that it works (only with TLS with my current configuration, see above).
>>> 
>>>> I can try this in a few days. Feel free to experiment with this yourself.
>>>> 
>>>> Regards,
>>>> 
>>>> Stephan.
>>> Thanks again,
>>> Paul
>>> 
>>> 
>>> 
>>> 
>>> -- 
>>> Best regards,
>>> Odhiambo WASHINGTON,
>>> Nairobi,KE
>>> +254 7 3200 0004/+254 7 2274 3223
>>> "Oh, the cruft."