Aleksei Shpakovskii:
> Hi,
>
> I would like to verify recipient address before hitting DNS RBL. But
> it seems I'm unable to do this. Am I doing something wrong?
>
> Using 32-bit Postfix 3.6.0-r0 from Alpine inside Docker container.
>
> My main.cf file looks like this:
>
> ##### main.cf #####
> mydomain=example.net
> compatibility_level=3
> maillog_file = /dev/stdout
> mydestination=$mydomain
> smtpd_recipient_restrictions = permit_mynetworks,
> permit_sasl_authenticated,
> reject_unauth_destination,
> reject_unverified_recipient,
> reject_rbl_client bogons.cymru.com
Something has broken reject_unverified_recipient but you should
probably be using reject_unlisted_recipient instead.
Wietse
> ##### main.cf #####
>
> where bogons.cymru.com is DNS RBL which conveniently blocks docker IP
> address (172.17.42.1).
>
> Telnet session (lower in this message) cites the RBL list as a block
> reason, and in the mail log (at the very end of this message) I can
> see a failed attempt to deliver a probe message (unknown user:
> "notauser") before sending a DNS request (Client host [172.17.42.1]
> blocked using bogons.cymru.com) - also note a 3 second delay before
> this log message.
>
> Am I doing something obviously wrong or can it be a quirk of my local
> system (Docker version 1.6.2 on 32-bit Ubuntu 14.04)? If anybody tries
> to reproduce it on different configurations - that might be also
> helpful.
>
> Thanks in advance!
>
> ##### telnet session #####
> 220 52fca4186025.example.net ESMTP Postfix
> EHLO test.example.com
> 250-52fca4186025.example.net
> 250-PIPELINING
> 250-SIZE 10240000
> 250-VRFY
> 250-ETRN
> 250-ENHANCEDSTATUSCODES
> 250-8BITMIME
> 250-DSN
> 250-SMTPUTF8
> 250 CHUNKING
> MAIL FROM:<t...@example.com>
> 250 2.1.0 Ok
> rcpt to:notau...@example.net
> 554 5.7.1 Service unavailable; Client host [172.17.42.1] blocked using
> bogons.cymru.com
> quit
> 221 2.0.0 Bye
> ##### telnet session #####
>
> ##### mail log #####
> May 12 22:35:20 52fca4186025 postfix/smtpd[81]: connect from
> unknown[172.17.42.1]
> May 12 22:35:56 52fca4186025 postfix/verify[85]: cache
> lmdb:/var/lib/postfix/verify_cache full cleanup: retained=0 dropped=0
> entries
> May 12 22:35:56 52fca4186025 postfix/cleanup[86]: CC153163658:
> message-id=<20210512223556.cc153163...@52fca4186025.example.net>
> May 12 22:35:56 52fca4186025 postfix/qmgr[74]: CC153163658:
> from=<double-bou...@52fca4186025.example.net>, size=263, nrcpt=1
> (queue active)
> May 12 22:35:56 52fca4186025 postfix/local[87]: CC153163658:
> to=<notau...@example.net>, relay=local, delay=0.02,
> delays=0.01/0.01/0/0, dsn=5.1.1, status=undeliverable (unknown user:
> "notauser")
> May 12 22:35:56 52fca4186025 postfix/qmgr[74]: CC153163658: removed
> May 12 22:35:59 52fca4186025 postfix/smtpd[81]: NOQUEUE: reject: RCPT
> from unknown[172.17.42.1]: 554 5.7.1 Service unavailable; Client host
> [172.17.42.1] blocked using bogons.cymru.com; from=<t...@example.com>
> to=<notau...@example.net> proto=ESMTP helo=<test.example.com>
> May 12 22:36:06 52fca4186025 postfix/smtpd[81]: disconnect from
> unknown[172.17.42.1] ehlo=1 mail=1 rcpt=0/1 quit=1 commands=3/4
> ##### mail log #####
>
