Delivery to mail@domain.tld failed with code 444, [Errno 111] Connection refused
Hi together,
I´m using Mailman3.3.9 and postfix in docker containers seperatly. Everything worked fine since this afternoon.
The error occurs, after postfix transports an incoming mail to mailman. After processing the mail, sending to all recepients failed
Delivery to mail@domain.tld failed with code 444, [Errno 111] Connection refused I checked the configuration of postfix and added a wide IP-range to mynetworks:
postfix-main.cf mynetworks = mailman-core tgc_mailman_core t 127.0.0.0/8 [::1]/128 [fe80::]/64 172.18.0.0/16 172.21.0.0/16 [2001:8d8:1800:283]/64 172.0.0.0/24 relay_domains = $mydestination #smtpd_sender_restrictions = reject_unknown_sender_domain,reject_unknown_reverse_client_hostname smtpd_sender_restrictions = reject_unknown_sender_domain smtpd_relay_restrictions = permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination smtpd_recipient_restrictions = permit_sasl_authenticated check_recipient_access hash:/etc/postfix/filtered_domains permit_mynetworks reject_unauth_destination smtpd_data_restrictions = reject_unauth_pipelining
Does anyone have a clue for me as to why delivery to Postfix is failing?
My last change a couple of days ago was adding an public ipv6-address to the host. But docker still works without IPv6. I thought about client-identification issues between maiolman-core and postfix but did noch find anything to fix ...
Best regards, Christopher
I identified the restriction
smtpd_sender_restrictions = reject_unknown_reverse_client_hostname which blocks the connection from mailman in postfix. I have no idea why mailman sends its mails by IP instead by containernam/hostname as before. Probably this relates with IPv6 activation ....
christopher.claus@tgcamberg1848.de writes:
I identified the restriction
smtpd_sender_restrictions = reject_unknown_reverse_client_hostname which blocks the connection from mailman in postfix. I have no idea why mailman sends its mails by IP instead by containernam/hostname as before. Probably this relates with IPv6 activation ....
I am sure that Mailman has nothing to do with this problem, and almost sure that Postfix is not responsible for it. This is not a murder case, where the reporter of the crime is the obvious suspect. It is an Internet failure case, where the #1 suspect is a constant: DNS.
What is very likely happening is that IPv6 is preferred over IPv4, and your DNS doesn't have a PTR record for the IPv6 address of the mailman container. That means the reverse lookup fails, and the message is blocked.
Steve
participants (2)
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christopher.claus＠tgcamberg1848.de -
Stephen J. Turnbull