Dear list,
I'm chasing a strange phenomenon with Postfix 3.5.6. I deliver virtual
emails through LMTP to Dovecot. That works well. Now I'd also like to
check the user's quota using Dovecot's quota service as described at
https://doc.dovecot.org/configuration_manual/quota_plugin/#quota-service
Relevant Postfix config:
smtpd_recipient_restrictions = \
reject_unauth_destination \
check_policy_service inet:localhost:12340
I usually test any mail server using swaks
(http://jetmore.org/john/code/swaks/). So I ran:
swaks --to t...@bullseye.example.org
The test user is over quota but Dovecot still replies with DUNNO instead
of rejecting the email. So I used tcpdump to look into the lines that
Postfix sends on port 12340 to the policy service:
request=smtpd_access_policy
protocol_state=RCPT
protocol_name=ESMTP
client_address=…
client_name=…
client_port=41000
reverse_client_name=…
server_address=…
server_port=25
helo_name=yoda.example.org
sender=r...@yoda.example.org
recipient=t...@bullseye.example.org
recipient_count=0
queue_id=
instance=acde.6101de59.d9386.0
size=0
[…]
My Postfix log shows though:
postfix/qmgr[43700]: A031B9D69C: from=<r...@yoda.example.org>, size=501,
nrcpt=1 (queue active)
What might be happening here? Postfix sends "recipient_count=0" and
"size=0" although it logs that there is one recipient and the email has
a size of 501 bytes.
At first I suspected swaks because it does not send a SIZE=… argument
along with the RCPT TO. Then I checked
http://www.postfix.org/SMTPD_POLICY_README.html and found:
"The "size" attribute value specifies the message size that the client
specified in the MAIL FROM command (zero if none was specified). With
Postfix 2.2 and later, it specifies the actual message size after the
client sends the END-OF-MESSAGE."
I do not encounter this when sending emails through Thunderbird. But I
would still like to know the reason that it fails with swaks. After all
swaks is just doing a regular SMTP connection AFAICT:
=== Trying bullseye.example.org:25...
=== Connected to bullseye.example.org.
<- 220 bullseye ESMTP Postfix (Debian/GNU)
-> EHLO yoda.example.org
<- 250-bullseye
<- 250-PIPELINING
<- 250-SIZE 10240000
<- 250-VRFY
<- 250-ETRN
<- 250-STARTTLS
<- 250-ENHANCEDSTATUSCODES
<- 250-8BITMIME
<- 250-DSN
<- 250-SMTPUTF8
<- 250 CHUNKING
-> MAIL FROM:<r...@yoda.example.org>
<- 250 2.1.0 Ok
-> RCPT TO:<t...@bullseye.example.org>
<- 250 2.1.5 Ok
-> DATA
<- 354 End data with <CR><LF>.<CR><LF>
-> Date: Thu, 29 Jul 2021 18:44:32 +0200
-> To: t...@bullseye.example.org
-> From: r...@yoda.example.org
-> Subject: test Thu, 29 Jul 2021 18:44:32 +0200
-> Message-Id: <20210729184432.012...@yoda.example.org>
-> X-Mailer: swaks v20181104.0 jetmore.org/john/code/swaks/
->
-> This is a test mailing
->
->
-> .
<- 250 2.0.0 Ok: queued as A031B9D69C
-> QUIT
<- 221 2.0.0 Bye
=== Connection closed with remote host.
Any clues welcome. Been pulling my hair out the second day now.
…Christoph
