On 6/9/25 05:05, Mark Sapiro wrote:

On 6/8/25 16:04, Florian Sukup wrote:

...

I set up mailman, created a site/domain (lists.yyy.com). My hostname is host.xxx.com . My IP has a RDNS entry: reverse.rrr.com .

Why is the RDNS to reverse.rrr.com and not host.xxx.com. It is important for mail delivery to have full circle DNS. I.e. the sending server should have an A record for its IP and revers DNS for that IP should point back to the sending server's name. I'm guessing that rrr.com is a hosting provider and you don't control the rDNS for that IP, but you should try to get them to change it for you. Without that change, delivery of your outbound mail, at least to large ISPs, will be problematic at best.

The setup has historic reasons. However I can eliminate reverse.rrr.com completely and replace it by host.xxx.com. Right now reverse.rrr.com has an A-record pointing to the host's ip address.

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When I send an email to my mailing list mylist@lists.yyy.com I receive an error email. The logfile says the following:

... Jun  9 00:23:38 arvak postfix/relay/smtp[]: 094895FADB: to=<mylist@lists.yyy.com>, relay=reverse.rrr.com[m.y.i.p]:25, delay=0.06, delays=0.03/0.01/0.02/0, dsn=5.4.6, status=bounced (mail for lists.yyy.com loops back to myself)

What is the output from postconf -n?

alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases append_dot_mydomain = no biff = no compatibility_level = 2 inet_interfaces = all inet_protocols = all local_recipient_maps = proxy:unix:passwd.byname $alias_maps hash:/var/lib/mailman3/data/postfix_lmtp mailbox_size_limit = 0 message_size_limit = 0 mydestination = localhost, localhost.localdomain, arvak myhostname = host.xxx.com mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128, 192.168.77.0/24 myorigin = /etc/mailname owner_request_special = no readme_directory = no recipient_delimiter = + relay_domains = ${{$compatibility_level} < {2} ? {$mydestination} : {}} hash:/var/lib/mailman3/data/postfix_domains relayhost = smtp_tls_CApath = /etc/ssl/certs smtp_tls_cert_file = /etc/letsencrypt/live/host.xxx.com/fullchain.pem smtp_tls_key_file = /etc/letsencrypt/live/host.xxx.com/privkey.pem smtp_tls_loglevel = 3 smtp_tls_security_level = may smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtp_use_tls = yes smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU) smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination smtpd_tls_cert_file = /etc/letsencrypt/live/host.xxx.com/fullchain.pem smtpd_tls_key_file = /etc/letsencrypt/live/host.xxx.com/privkey.pem smtpd_tls_loglevel = 3 smtpd_tls_security_level = may smtpd_use_tls = yes transport_maps = hash:/var/lib/mailman3/data/postfix_lmtp virtual_alias_domains = 9 different domains, however not host.xxx.com, lists.yyy.com or reverse.rrr.com virtual_alias_maps = hash:/etc/postfix/virtual

...

Jun  9 00:23:38 arvak postfix/smtpd[114119]: disconnect from host.xxx.com[m.y.i.p] ehlo=1 quit=1 commands=2 ...

The MX record of lists.yyy.com points to reverse.rrr.com. Not sure if this is the best idea?

reverse.rrr.com has no A or AAAA record. An MX MUST point to a domain that has an A or AAAA record. The MX should point to host.xxx.com.

Will be resolved (s. above).

...

Can anyone give me a hint where to search for this error?

The output from postconf -n would help. Also, have you set up postfix per https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.ht... ?

Basically yes, but I see a few differences which all worked on my test installation. Here comes my mailman.cfg:

[mailman] site_owner: mailman@... noreply_address: noreply default_language: en sender_headers: from from_ reply-to sender email_commands_max_lines: 10 pending_request_life: 3d cache_life: 7d pre_hook: post_hook: layout: debian filtered_messages_are_preservable: no html_to_plain_text_command: /usr/bin/lynx -dump $filename listname_chars: [-_.0-9a-z]

[shell] prompt: >>> banner: Welcome to the GNU Mailman shell use_ipython: no history_file:

[paths.debian] var_dir: /var/lib/mailman3 queue_dir: $var_dir/queue bin_dir: /usr/lib/mailman3/bin list_data_dir: $var_dir/lists log_dir: /var/log/mailman3 lock_dir: $var_dir/locks data_dir: $var_dir/data cache_dir: $var_dir/cache etc_dir: /etc/mailman3 ext_dir: $var_dir/ext messages_dir: $var_dir/messages archive_dir: $var_dir/archives template_dir: $var_dir/templates pid_file: /run/mailman3/master.pid lock_file: $lock_dir/master.lck

[database] class: mailman.database.sqlite.SQLiteDatabase url: sqlite:///$DATA_DIR/mailman.db debug: no

[logging.debian] format: %(asctime)s (%(process)d) %(message)s datefmt: %b %d %H:%M:%S %Y propagate: no level: info path: mailman.log

[webservice] hostname: localhost port: 8001 use_https: no show_tracebacks: yes api_version: 3.1 admin_user: ... admin_pass: ...

[mta] incoming: mailman.mta.postfix.LMTP outgoing: mailman.mta.deliver.deliver smtp_host: localhost smtp_port: 25 smtp_user: smtp_pass: lmtp_host: 127.0.0.1 lmtp_port: 8024 configuration: python:mailman.config.postfix

Thanks for your help, Florian.