TCB13 , 10 months ago (edited 10 months ago)

Dovecot + Postfix + Rspamd can do it. Instead of pulling emails you can simply forward those providers to your homeserver account. You may also setup Postfix in a way that would allow you to use our @gmail @hotmail addresses as “from” addresses / aliases to your local account and it will automatically submit the email through the provider SMTP server when you send something.

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If you really want to pull email instead of setting up forwards (have your server offline more time and whatnot) there are a few options:

• www.fetchmail.info - the classic tool for the job
• github.com/getmail6/getmail6 - another classic solution
• github.com/mback2k/go-getmail - probably what I would use today

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To route the outgoing email through the right provider / external SMTP server based on the “from” address you may configured it like this:

main.cf:

<span style="color:#323232;">smtp_sasl_auth_enable = yes
</span><span style="color:#323232;">smtp_sender_dependent_authentication = yes
</span><span style="color:#323232;">smtp_sasl_password_maps = mysql:/etc/postfix/virtual/mysql-external-alias-credentials.cf
</span><span style="color:#323232;">sender_dependent_relayhost_maps = mysql:/etc/postfix/virtual/mysql-external-alias-relay-hosts.cf
</span><span style="color:#323232;">smtp_sasl_security_options = noanonymous
</span>

mysql-external-alias-credentials.cf:

<span style="color:#323232;">user = XXXXX
</span><span style="color:#323232;">password = XXXXXX
</span><span style="color:#323232;">hosts = 127.0.0.1
</span><span style="color:#323232;">dbname = mailserver
</span><span style="color:#323232;">query = SELECT concat(relay_user, ':', relay_passwd) AS credential FROM `Virtual_Alias_External` WHERE alias='%s' AND active = 1;
</span>

mysql-external-alias-relay-hosts.cf:

<span style="color:#323232;">user = XXXXX
</span><span style="color:#323232;">password = XXXXXX
</span><span style="color:#323232;">hosts = 127.0.0.1
</span><span style="color:#323232;">dbname = mailserver
</span><span style="color:#323232;">query = SELECT relay_host AS transport FROM `Virtual_Alias_External` WHERE alias='%s' AND active = 1;
</span>

MySQL table structure:

<span style="color:#323232;">CREATE TABLE `Virtual_Alias_External` (
</span><span style="color:#323232;">  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
</span><span style="color:#323232;">  `alias` varchar(70) NOT NULL,
</span><span style="color:#323232;">  `owner` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,
</span><span style="color:#323232;">  `active` tinyint(1) NOT NULL DEFAULT 0,
</span><span style="color:#323232;">  `relay_host` varchar(70) NOT NULL DEFAULT '',
</span><span style="color:#323232;">  `relay_user` varchar(70) NOT NULL,
</span><span style="color:#323232;">  `relay_passwd` varchar(70) NOT NULL,
</span><span style="color:#323232;">  PRIMARY KEY (`id`) USING BTREE
</span><span style="color:#323232;">) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=COMPACT;
</span>

Create an entry like this:

<span style="color:#323232;">alias: [email protected]
</span><span style="color:#323232;">owner: [email protected]
</span><span style="color:#323232;">active: 1
</span><span style="color:#323232;">relay_host: [smtp.gmail.com]:587
</span><span style="color:#323232;">relay_user:  [email protected]
</span><span style="color:#323232;">relay_passwd: your-gmail-password-or-app-password
</span>

Now when you send and email and the from is set as [email protected] Postfix will route the email through Gmail’s SMTP server with credential stored on that table. If done correctly (smtpd_sasl_authenticated_header = no) no references to [email protected] will show up on the email headers.