Issue Mail: +alias@example.com does not work (recipient_delimiter = +)

[GerdSchrewe]

Ubuntu 18.04, Plesk 17.8.11, Update 69. Postfix and Dovecot.

Problem:
When i send an E-Mail to info@example.com everything works fine.
When i send an E-Mail to info+anything@example.com the mail is not delivered and simply vanishes, but in maillog appears: status=sent (delivered via plesk_virtual service)

mail.error:
Oct 6 18:30:36 server2 postfix-local[1997]: cannot chdir to mailname dir info+anything: No such file or directory
Oct 6 18:30:36 server2 postfix-local[1997]: Unknown user: info+anything@example.com

maillog:
server2:~# less /var/log/mail.log
Oct 6 18:30:36 server2 postfix/qmgr[1136]: 6A3AA1201916: from=<support@xyz.de>, size=1821, nrcpt=1 (queue active)
Oct 6 18:30:36 server2 postfix-local[1997]: postfix-local: from=support@xyz.de, to=info+anything@example.com
=/var/qmail/mailnames
Oct 6 18:30:36 server2 postfix/smtpd[1425]: disconnect from web4.xyz.de[88.xxx.xxx.xxx] ehlo=2 starttls=1 mail=1 rcpt=1 data=1 quit=1 commands=7
Oct 6 18:30:36 server2 postfix-local[1997]: cannot chdir to mailname dir info+anything: No such file or directory
Oct 6 18:30:36 server2 postfix-local[1997]: Unknown user: info+anything@example.com
Oct 6 18:30:36 server2 postfix/pipe[1996]: 6A3AA1201916: to=<info+anything@example.com>, relay=plesk_virtual, delay=0.24, delays=0.22/0.01/0/0.01, dsn=2.0.0,
status=sent (delivered via plesk_virtual service)
Oct 6 18:30:36 server2 postfix/qmgr[1136]: 6A3AA1201916: removed

Is it a bug? Both adresses should work.
See:
recipient_delimiter (default: empty)
Postfix Configuration Parameters

# Handle Postfix-style extensions.
recipient_delimiter = +
# Handle both Postfix and qmail extensions (Postfix 2.11 and later).
recipient_delimiter = +-
Postfix Configuration Parameters


Thanx a lot for help!
Paul

 

[Aleix]

Hi Paul,

I had a problem similar to yours, but instead of alias@domain.com was name@alias.com
It seems it is something with Postfix

I tried these 2 solutions

The first one tells you that, if you have the line receive_override_options in /etc/postfix/main.cf or /etc/postix/master.cf, just comment it and restart Postfix
Mail aliases do not work on Plesk server: Unknown user: alias@domain.tld

If this does not help, try this one. It tells you to comment all the lines which starts with virtual in /etc/postfix/main.cf and restart Postfix
PLESK PostFix Error Local Loop in maillog, how to troubleshoot

The second option was the one which solved my problem.

Hope this helps!
Greetings.

 

[GerdSchrewe]

Hi Aleix, thank you very much for your suggestions.

Unfortunately this not the case!

Everything works fine with normal Mail-Aliases configured in Plesk. e.g.

- alias@domain.com <-- works fine


The bad error occurs when using a plus-alias Mail address like:

user+some-text-you-want@domain.com.

Such mails simply disappear / get lost!

This plus-alias is handled by the postfix config option "recipient_delimiter = +". This makes sure that every thing between + and @ is "removed" for finding the "real" user mailbox... so:

- user+some-text-you-want@domain.com ----resolves-postfix-internal-to----> user@domain.com

When you have a look at the postfix doku Postfix Configuration Parameters you can read the detailed Information.

In a normal postfix + dovecot setup postfix recieves a mail, checks if the "real real address" behind the plus-alias is existing and spools the Mail. Afterwords the mail would be forwarded to the LDA (local delivery agent), e.g. "dovecot-lda" which puts the mail into user's mailbox/inbox.

With the current Plesk setup, there is a special plesk application which does the LDA job.

It is configured as transport "plesk_virtual" (in main.cf/master.cf) which starts the program "/usr/lib/plesk-9.0/postfix-local".

When you have a look at the log of the 1st message, you will see:

- this transport is used: "relay=plesk_virtual"

- the postfix-local application produces errors: "cannot chdir..." & "Unknown user"

- BUT postfix-local sends an "OK" to the postfix, so postfix thinks the Mail is delivered: "status=sent (delivered via plesk_virtual service)"

...unfortunately, there is no mail delivered at all.

So there are 2 Problems with the plesk-local program:

1.) when plesk-local is failing, it *must* return a bad error-code to postfix, so postfix could deliver a temp SMTP error -> plesk-local has to be fixed

example smtp error on lda failure: "451 4.3.0 Error: queue file write error"

2.) a configured recipient_delimiter should be handled in a correct way. -> postfix config has to be updated (fix address_mapping)

Note: In a normal postfix + dovecot setup postfix, the mapping of the plus-alias is done at postfix side. When using multiple transports for spam-filtering, you have to set the smtpd option "receive_override_options=no_address_mappings" to prevent the rewrite.

This Log shows the line with address_mapping on a standard postfix+dovecot installation:
postfix/pipe[2148]: 92CD62998F: to=<user@domain.de>, orig_to=<user+aliastest@domain.de>, relay=dovecot, delay=0.25, delays=0.12/0.01/0/0.12, dsn=2.0.0, status=sent (delivered via dovecot service)

So, I guess, this issue has definitely to be handled by a staff member / developer of plesk!

 

[mow]

See Postfix: Not delivering messages with recipient delimiter

in master.cf, change

plesk_virtual unix - n n - - pipe flags=DORhu user=popuser:popuser argv=/usr/lib/plesk-9.0/postfix-local -f ${sender} -d ${recipient} -p /var/qmail/mailnames

to

plesk_virtual unix - n n - - pipe flags=DORhu user=popuser:popuser argv=/usr/lib/plesk-9.0/postfix-local -f ${sender} -d ${user}@${nexthop} -p /var/qmail/mailnames

and do a `postfix reload`.

 

[GerdSchrewe]

Thanx a lot!!!

 

[Toxalot]

There are two related feature requests that I created over 6 years ago.

Maybe if they got more votes, they'd get implemented.

• Have an option to deliver email addressed to VERP-style email addresses.
• Allow customization of /etc/postfix/main.cf

 

[Thomas_Beale]

I have just made the above changes to /etc/postfix/master.cf, and they do work (Plesk Onyx/Debian/postfix 3.x). My case was to enable plus-addressed replies to mail from Discourse (forums tool). The more generic (i.e. if you don't have Plesk) fixes described here don't actually solve the problem (it is not clear to me if they are needed or not; I left them in).

 

[NaSOnWeb]

I don't know but master.cf seem to be overwriten when updatinf plesk
may be we could use a script to replace the line with a cron

#!/bin/bash

OLD_REGEX="plesk_virtual unix - n n - - pipe flags=DORhu user=popuser:popuser argv=\/usr\/lib\/plesk-9\.0\/postfix-local -f \${sender} -d \${recipient}"

NEW="plesk_virtual unix - n n - - pipe flags=DORhu user=popuser:popuser argv=\/usr\/lib\/plesk-9.0\/postfix-local -f \${sender} -d \${user}@\${nexthop}"

sed -i "s/$OLD_REGEX/$NEW/g" /etc/postfix/master.cf