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another diagram; delivery process; main.cf and master.cf; example correction
 
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<hide>
[[page type::article]]
[[thing type::software]]
[[software type::mail transfer agent]]
[[architecture::server]]
[[license::open source]]
[[category:software]]
</hide>
==About==
==About==
[[category:software]][[Postfix]] is an [[open-source]] [[mail transfer agent]] (MTA) for [[POSIX]] systems. It is fully supported by [[Webmin]] and is part of the [[Dovecot]] stack.
[[Postfix]] is an [[open source]] [[mail transfer agent]] (MTA) for [[POSIX]] systems. It is fully supported by [[Webmin]]/[[VirtualMin]] and is part of the [[Dovecot]] stack.
===Pages===
* [[/aliasing]]: managing email redirects/aliases
* [[/fixing]]: diagnosis of installations that aren't working right
* see also: [[DKIM]], [[DMARC]], [[Sender Policy Framework]] (SPF)
* [[/chroot]]: running Postfix in a [[chroot]]ed environment
 
===Files===
===Files===
* [[/main.cf]]
* [[/main.cf]]
* [[/master.cf]]: formatted list of transport helper applications
* [[/master.cf]]: formatted list of transport helper applications
==Notes==
* [[/mail.log]] (typically found in /var/log)
After making changes to the Postfix configuration files, you don't actually have to stop and restart Postfix to load the changes; you can just type (as root) "postfix reload".
===Internal Apps===
===flow===
* [[/aliases]] ([http://www.postfix.org/aliases.5.html reference])
There are multiple stages inside Postfix, and each stage can be affected by configuration parameters. I have not yet found a clear documentation of the data flow, but it seems to go like this (only much more complicated) under normal circumstances:
* [[/cleanup]] ([http://postfix.org/cleanup.8.html reference])
* [[/lmtp]] ([http://postfix.org/lmtp.8.html reference])
* [[/local]] ([http://postfix.org/local.8.html reference])
* [[/pickup]] ([http://postfix.org/pickup.8.html reference])
* [[/qmgr]] ([http://postfix.org/qmgr.8.html reference])
* [[/smtpd]] ([http://postfix.org/smtpd.8.html reference])
* [[/transport]] ([http://www.postfix.org/transport.5.html reference])
* [[/trivial-rewrite]] ([http://postfix.org/trivial-rewrite.8.html reference]))
===User Applets===
* [[/newaliases]]
===Other Applets===
These are installed as part of the postfix package; not sure how they should be classified:
{|
|-
| valign=top |
* '''/usr/bin''':
** [[/mailq]]
** [[/newaliases]] - user utility
** [[/rmail]]
* '''/usr/lib''':
** [[/postfix_groups.pl]]
** [[/sendmail]]
| valign=top |
* '''/usr/lib/postfix''':
** [[/anvil]]
** [[/bounce]]
** [[/cleanup]]
** [[/discard]]
** [[/error]]
** [[/flush]]
** [[/fsstone]]
** [[/lmtp]]
** [[/local]]
** [[/master]]
** [[/oqmgr]]
** [[/pickup]]
** [[/pipe]]
** [[/post-install]]
** [[/postfix-files]]
** [[/postfix-script]]
** [[/postfix-wrapper]]
** [[/postmulti-script]]
** [[/proxymap]]
** [[/qmgr]]
** [[/qmqpd]]
** [[/scache]]
** [[/showq]]
** [[/smtp]]
** [[/smtpd]]
** [[/spawn]]
** [[/tlsmgr]]
** [[/trivial-rewrite]]
** [[/verify]]
** [[/virtual]]
| valign=top |
* '''/usr/sbin''':
** [[/postalias]]
** [[/postcat]]
** [[/postconf]]
** [[/postdrop]]
** [[/postfix]] - core binary
** [[/postfix-add-filter]]
** [[/postfix-add-policy]]
** [[/postkick]]
** [[/postlock]]
** [[/postlog]]
** [[/postmap]]
** [[/postmulti]]
** [[/postqueue]]
** [[/postsuper]]
** [[/qmqp-sink]]
** [[/qmqp-source]]
** [[/qshape]]
** [[/rmail]]
** [[/sendmail]]
** [[/smtp-sink]]
** [[/smtp-source]]
|}


: [[SMTP]] &rarr; Postfix delivery queue &rarr; user alias mappings &rarr; [[mail delivery agent|local delivery]] (MDA, e.g. [[Dovecot]])
===Error Messages===
* [[503 5.5.1 Error: authentication not enabled]]
* [[Connect to private/dovecot-auth failed: No such file or directory]]


However, when using virtual (non-system) users, internally-generated emails (e.g. mail from [[cron]] or [[PHP]]'s mail() function) seem to bypass the alias mappings, which the MDA then rejects if they are addressed to an alias instead of a user.
===Other Subpages===
* [[/flow]]: the flow of messages across the various helper programs that make up Postfix
* [[/SSL]]: Postfix and SSL


A table from the official documentation is more detailed, if perhaps less clear (where does the message ''end up''? qmgr? how does it get delivered?):
==Notes==
<table align=center>
After making changes to the Postfix configuration files, you don't actually have to stop and restart Postfix to load the changes; you can just type (as root) "postfix reload".
<tr>
<td colspan="2"> </td>
<td align="center" bgcolor="#f0f0ff"> [http://postfix.org/trivial-rewrite.8.html trivial-<br>rewrite(8)]<br>(std
form) </td>
<td colspan="5"> </td>
<td align="center" bgcolor="#f0f0ff"> [http://postfix.org/trivial-rewrite.8.html trivial-<br>rewrite(8)]<br>(resolve)
</td>
</tr>
<tr>
<td colspan="2"> </td>
<td align="center"><table><tr><td align="center"> ^<br> <tt> |
</tt> </td><td align="center"> <tt> |<br>v </tt> </td></tr></table>
</td><td colspan="5"> </td>
<td align="center"><table><tr><td align="center"> ^<br> <tt> |
</tt> </td><td align="center"> <tt> |<br>v </tt> </td></tr></table>
</td><td colspan="2"> </td>
</tr>
<tr>
<td valign="middle" align="center" bgcolor="#f0f0ff"> [http://postfix.org/smtpd.8.html smtpd(8)]
</td>
<td rowspan="3" valign="middle" align="center"> <tt> &gt;- </tt>
</td>
<td rowspan="3" align="center" bgcolor="#f0f0ff"> [http://postfix.org/cleanup.8.html cleanup(8)] </td>
<td rowspan="3" valign="middle" align="center"> <tt> -&gt; </tt>
</td>
<td rowspan="3" align="center" bgcolor="#f0f0ff"> [http://postfix.org/QSHAPE_README.html#incoming_queue incoming] </td>
<td rowspan="3" valign="middle" align="center"> <tt> -&gt; </tt>
</td>
<td rowspan="3" align="center" bgcolor="#f0f0ff"> [http://postfix.org/QSHAPE_README.html#active_queue active] </td>
<td rowspan="3" valign="middle" align="center"> <tt> -&gt; </tt>
</td>
<td rowspan="3" align="center" bgcolor="#f0f0ff"> [http://postfix.org/qmgr.8.html qmgr(8)]</td>
<td rowspan="3" valign="middle" align="center"> <tt> -&lt; </tt>
</td>
<td valign="middle" align="center" bgcolor="#f0f0ff">
[http://postfix.org/smtp.8.html smtp(8)]</td>
</tr>
<tr>
<td valign="middle" align="center" bgcolor="#f0f0ff">
[http://postfix.org/qmqpd.8.html qmqpd(8)]</td>
<td valign="middle" align="center" bgcolor="#f0f0ff"> [http://postfix.org/lmtp.8.html lmtp(8)]</td>
</tr>
<tr>
<td valign="middle" align="center" bgcolor="#f0f0ff"> [http://postfix.org/pickup.8.html pickup(8)]
</td>
<td valign="middle" align="center" bgcolor="#f0f0ff"> [http://postfix.org/local.8.html local(8)]
</td>
</tr>
<tr>
<td colspan="2"> </td>
<td align="center"> ^<br> <tt> | </tt> </td>
<td colspan="3"> </td>
<td align="center"><table><tr><td align="center"> ^<br> <tt> |
</tt> </td><td align="center"> <tt> |<br>v </tt> </td></tr></table>
</td><td colspan="4"> </td>
</tr>
<tr>
<td colspan="2"> </td>
<td align="center"> bounces<br> forwarding<br> notices</td>
<td colspan="3"> </td>
<td align="center" bgcolor="#f0f0ff"> [http://postfix.org/QSHAPE_README.html#deferred_queue deferred]
</td><td colspan="2"> </td>
</tr>
</table>
There are two more diagrams [http://www.postfix.org/OVERVIEW.html here]; the first shows the input stage in a bit more detail, and the second shows the delivery stage.
===aliases===
To set up aliases, either edit the file specified by the [[/main.cf/alias_maps|alias_maps]] setting in [[/main.cf|main.cf]] ([[etc/aliases|/etc/aliases]] by default) and then run [[newaliases]] (or "postalias /etc/aliases") to update the database, or else use [[Webmin]] ("Mail Aliases" icon, then click on the "Create a new alias" link).
 
'''Notes''':
* Webmin seems to automatically run newaliases when you add or modify an individual alias, but ''not'' when you use it to edit the [[etc/aliases|/etc/aliases]] file directly. Changes made to /etc/aliases will not take effect until the database is updated.
* Stopping and starting the postfix daemon does ''not'' update from the aliases file; you still have to run newaliases.
===virtual users===
By default, virtual aliases seem to get looked up only when email comes from the outside; locally generated emails are "returned" as undeliverable with the error message "Diagnostic-Code: x-unix; user unknown"
 
The following change in main.cf solves that problem &ndash;
* '''change''': {{link/subpage|pfx=/main.cf/|receive_override_options}} = no_address_mappings
* '''to this''': receive_override_options =
&ndash; but creates a new one, in that externally-sourced messages are now delivered ''twice'' (or ''four'' times if addressed directly to a virtual user instead of a virtual alias).
 
Someone who understands the internal structure of postfix could probably figure out what this means (and how to fix it), but I'm still working on it.
 
===catch-all===
To set up a catch-all address, edit {{link/subpage|main.cf}} and set the following parameters:
* {{link/subpage|pfx=/main.cf/|local_recipient_maps}} =
* {{link/subpage|pfx=/main.cf/|luser_relay}} = <u>whereToSend</u>
 
The syntax for <u>whereToSend</u> is explained [http://www.postfix.org/postconf.5.html#luser_relay here].


Examples:
* luser_relay = $user@anotherdomain.org
** forwards all email addressed to "invaliduser@firstdomain.org" to "invaliduser@anotherdomain.org"
* luser_relay = youraddress@anotherdomain.org
** forwards all email addressed to invalid users to "youraddress@anotherdomain.org".
===automatic BCC===
===automatic BCC===
To automatically [[blind carbon copy|BCC]] outgoing mail ''from'' any given set of users, set [[/main.cf/sender_bcc_maps|sender_bcc_maps]] in [[/main.cf]] to <u>hash:/etc/postfix/sender_bcc</u>. (In [[Webmin]]: BCC Mapping: Sender BCC mapping lookup tables)
To automatically [[blind carbon copy|BCC]] outgoing mail ''from'' any given set of users, set [[/main.cf/sender_bcc_maps|sender_bcc_maps]] in [[/main.cf]] to <u>hash:/etc/postfix/sender_bcc</u>. (In [[Webmin]]: BCC Mapping: Sender BCC mapping lookup tables)
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  @vbz.com archive{{CURRENTYEAR}}@vbz.com
  @vbz.com archive{{CURRENTYEAR}}@vbz.com
===pages to index===
===pages to index===
I have these open in tabs, so they are probably relevant to something:
Possibly useful pages:
* [https://www.howtoforge.com/postfix_backup_mx Setting Up Postfix As A Backup MX]
* [http://www.postfix.org/ADDRESS_REWRITING_README.html Postfix Address Rewriting]
* [http://www.postfix.org/ADDRESS_REWRITING_README.html Postfix Address Rewriting]
* [http://www.postfix.org/trivial-rewrite.8.html trivial-rewrite] (manpage)
* [http://www.postfix.org/trivial-rewrite.8.html trivial-rewrite] (manpage)
* [http://www.postfix.org/postconf.5.html Postfix Configuration Parameters] (includes [[/main.cf]] parameters)
* [http://www.postfix.org/postconf.5.html Postfix Configuration Parameters] (includes [[/main.cf]] parameters)
* [http://www.postfix.org/FILTER_README.html Postfix After-Queue Content Filter]
* [http://www.group-office.com/wiki/Mailserver Group-Office Mailserver] plugin: helps administer Postfix
* [http://en.gentoo-wiki.com/wiki/Mail_server_using_Postfix_and_Dovecot Mail server using Postfix and Dovecot] on [[Gentoo Linux]]
==Links==
==Links==
===Official===
===Official===
* [http://www.postfix.org/ home page]
* [http://www.postfix.org/ home page]
* {{link/manpage/only|Postfix|manpage}}
===Reference===
===Reference===
* {{wikipedia|Postfix (software)}}
* {{wikipedia|Postfix (software)}}
* [http://postfix.wiki.xs4all.nl/ wiki]
** [http://postfix.wiki.xs4all.nl/index.php?title=Relay_recipient_maps_using_LDAP_against_Active_Directory Relay recipient maps using LDAP against Active Directory]

Latest revision as of 16:00, 17 September 2021

<hide> page type::article thing type::software software type::mail transfer agent architecture::server license::open source </hide>

About

Postfix is an open source mail transfer agent (MTA) for POSIX systems. It is fully supported by Webmin/VirtualMin and is part of the Dovecot stack.

Pages

Files

Internal Apps

User Applets

Other Applets

These are installed as part of the postfix package; not sure how they should be classified:

Error Messages

Other Subpages

  • /flow: the flow of messages across the various helper programs that make up Postfix
  • /SSL: Postfix and SSL

Notes

After making changes to the Postfix configuration files, you don't actually have to stop and restart Postfix to load the changes; you can just type (as root) "postfix reload".

automatic BCC

To automatically BCC outgoing mail from any given set of users, set sender_bcc_maps in /main.cf to hash:/etc/postfix/sender_bcc. (In Webmin: BCC Mapping: Sender BCC mapping lookup tables)

Each line in the /sender_bcc file will contain the sender (which can be user@domain, user, or @domain), one or more blanks, then the recipient (which can be one address or multiple addresses separated by commas).

Example -- BCCs all mail sent by vbz.com users to an archive address: 

@vbz.com archive2026@vbz.com

pages to index

Possibly useful pages:

Official

Reference

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