April 2021 - dovecot - dovecot.org

sieve filter bevor.spam, arnt take effect
by Maurizio Caloro 13 Apr '21

13 Apr '21

Hello Please willing to filter "bevor spam" mail... filtering arnt take effect .. please i dont see the mistake. Thanks for any possible update. Debian buster -- root@nmail:/etc/dovecot# dpkg -l | grep dovecot dovecot-core 1:2.3.4.1-5+deb10u6 dovecot-imapd 1:2.3.4.1-5+deb10u6 dovecot-lmtpd 1:2.3.4.1-5+deb10u6 dovecot-managesieved 1:2.3.4.1-5+deb10u6 dovecot-mysql 1:2.3.4.1-5+deb10u6 dovecot-sieve 1:2.3.4.1-5+deb10u6 root@nmail:/etc/dovecot/sieve# cat before.sieve # Sieve rules that are run before the user's filters. # Messages flagged as spam are moved into the Junk folder. require [ "fileinto", "mailbox" ]; if header :contains "X-Spam-Flag" "YES" { fileinto :create "INBOX.Junk"; stop; } -- already executed # sieve before.sieve -- service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { mode = 0600 user = postfix group = postfix } } -- root@nmail:/etc/dovecot/conf.d# <mailto:root@nmail:/etc/dovecot/conf.d#> cat 90-sieve.conf ## ## Settings for the Sieve interpreter ## plugin { # The path to the user's main active script. If ManageSieve is used, this the # location of the symbolic link controlled by ManageSieve. # sieve = ~/sieve/.dovecot.sieve sieve = file:%h/sieve;active=%h/.dovecot.sieve # Directory for :personal include scripts for the include extension. This # is also where the ManageSieve service stores the user's scripts. sieve_dir = ~/sieve # Path to a script file or a directory containing script files that need to be # executed before the user's script. If the path points to a directory, all # the Sieve scripts contained therein (with the proper .sieve extension) are # executed. The order of execution within a directory is determined by the # file names, using a normal 8bit per-character comparison. Multiple script # file or directory paths can be specified by appending an increasing number. sieve_before = /etc/dovecot/sieve/before.sieve } -- root@nmail:/etc/dovecot# doveconf -n # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.4 () # OS: Linux 4.19.0-16-amd64 x86_64 Debian 10.9 # Hostname: nmail.caloro.ch auth_mechanisms = plain login auth_verbose = yes info_log_path = /var/log/mail.log log_timestamp = %b %d %H:%M:%S Dovecot/ mail_access_groups = vmail mail_location = maildir:~/Maildir managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } plugin { sieve = ~/sieve/.dovecot.sieve sieve_dir = ~/sieve } postmaster_address = mca(a)caloro.ch <mailto:mca@caloro.ch> protocols = imap lmtp sieve service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } unix_listener auth-client { mode = 0660 user = mail } } service imap-login { inet_listener imap { port = 0 } inet_listener imaps { port = 993 ssl = yes } } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0600 user = postfix } } service stats { unix_listener stats-reader { group = vmail mode = 0666 user = vmail } unix_listener stats-writer { group = vmail mode = 0666 user = vmail } } ssl = required ssl_cert = </etc/letsencrypt/live/nmail.caloro.ch/fullchain.pem ssl_cipher_list = ECDHE-RSA-CHACHA20-POLY1305:ALL:!LOW:!SSLv2:!EXP:!aNULL ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it ssl_min_protocol = TLSv1.2 userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } protocol lda { mail_plugins = " quota sieve" } protocol imap { mail_plugins = " quota imap_quota" ssl_cert = </etc/letsencrypt/live/nmail.caloro.ch/fullchain.pem ssl_key = # hidden, use -P to show it } protocol lmtp { mail_plugins = " sieve" } Mauri

3 6

error 42 ssl certificate expired
by Christopher Wensink 13 Apr '21

13 Apr '21

Dovecot Team, I need a little help. I came in this morning and it seems like the SSL Certificates expired for dovecot (on an internal mail server) and nobody can move email into their folders on this server. In Thunderbird they just see in the status bar: HISTORY: checking mail server capabilities... In /var/log/maillog: -------- Apr 12 09:02:26 mario2 dovecot: imap-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=10.5.1.85, lip=10.5.1.17, TLS: SSL_read() failed: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42, session=<H5iu9sa/Me0KBQFV> I have tried: -Restarting Dovecot -Restarting the whole mail server -Re-creating the .pem files, first moving the old files in /etc/pki/dovecot/certs and /etc/pki/dovecot/private from dovecot.pem to dovecot-old.pem, - Re-creating a new dovecot.pem using the mkcert.sh script in the doc folder in /usr/share/doc/dovecot-2.2.36/, - restarting dovecot - changing the cert values in dovecot-openssl.cnf I also tried creating new .crt and key files using this tutorial: https://msol.io/blog/tech/create-a-self-signed-ssl-certificate-with-openssl/ I need some assistance, thank you for your help. Chris -- Christopher Wensink IS Administrator Five Star Plastics, Inc 1339 Continental Drive Eau Claire, WI 54701 Office: 715-831-1682 Mobile: 715-563-3112 Fax: 715-831-6075 cwensink(a)five-star-plastics.com www.five-star-plastics.com

4 8

Letsencrypt/OpenSSL test - Verify return code: 21
by Brady Shea 12 Apr '21

12 Apr '21

OS: Ubuntu 20.04.2 (on mutli-core VM) Dovecot (Ubuntu default/repo version): 2.3.7.2 (3c910f64b) OpenSSL (Ubuntu default/repo version): 1.1.1f 31 Mar 2020 Reproducing- Run: "openssl s_client -showcerts -connect imap.example.com:993 -servername imap.example.com" (using a diff domain obviously) Produces error: "Verify return code: 21 (unable to verify the first certificate)" (Meaning it is missing a CA verify from what I understand?) The "Verify return code: 21" error ONLY came to my attention after I had a customer complain about adding an email account to an Android phone (using the Google/Gmail default email app). -> "Certificate cannot be trusted" was shown by app when verifying imap connection. I could force it to be used, but this still bothered me, obviously. *The same certificate bundle is also used by smtp/postifx and www/nginx and works just fine. Also the openssl test shows 'verified' on both* I am posting to list mainly because on an older version of Dovecot I have running (default repo version for Ubuntu 18), I do not have this problem shown during testing with openssl. I did not have to change the ssl_cert or ssl_ca value in config. It has identical local.conf settings other than that. Granted it is also an older openssl version, too. So, I feel this may be a bug with Dovecot (or possibly OpenSSL). I finally 'fixed' it myself by using the LE 'fullchain.pem' certificate as the location for the 'ssl_cert' entry (and chain.pem for the ca entry). Previously, it was using the normal cert.pem file location. This is still the way it's setup on the other older machine and still works fine. Changes- |ssl_ca = </etc/letsencrypt/live/{CertName}/chain.pem (or 'fullchain.pem' should work) *ssl_cert = </etc/letsencrypt/live/{CertName}/fullchain.pem* (was 'cert.pem' previously) ssl_key = </etc/letsencrypt/live/{CertName}/privkey.pem| You can also view the problem here for more info : https://superuser.com/a/1640778/47628 Thanks ahead for any insight into this..

3 2

connection closed every ten minutes
by Marco Fioretti 12 Apr '21

12 Apr '21

Greetings, I use mutt on Ubuntu to access my IMAP mailboxes, on my Centos email server that runs dovecot. Everything has worked without problems for years. About one week ago, the connection between mutt and dovecot became unstable. Before, I could leave mutt connected for days in a row, no problem. Now, everything still works fine, except... I get every ten minutes I get "connection timed out" in Mutt's status line, and hundreds of messages like Apr 12 16:12:49 SERVERNAME dovecot: imap(ACCOUNTNAME): Logged out in=164 out=757 what puzzles me is that I did not touch anything both on my server and on my desktop, except an "apt-get update" some days before this started. But cannot see how it would be related anyway, nor have I found anything online like this. Any help to understand what happened and fix it is very welcome. Marco

1 0

AW: sieve filter bevor.spam, arnt take effect
by mauric＠gmx.ch 12 Apr '21

12 Apr '21

Please kindly want to ask for any possible update ? Von: mauric(a)gmx.ch <mauric(a)gmx.ch> Gesendet: Montag, 12. April 2021 10:44 An: 'dovecot(a)dovecot.org' <dovecot(a)dovecot.org> Betreff: sieve filter bevor.spam, arnt take effect Hello Please willing to filter "bevor spam" mail... filtering arnt take effect .. please i dont see the mistake. Thanks for any possible update. Debian buster -- root@nmail:/etc/dovecot# dpkg -l | grep dovecot dovecot-core 1:2.3.4.1-5+deb10u6 dovecot-imapd 1:2.3.4.1-5+deb10u6 dovecot-lmtpd 1:2.3.4.1-5+deb10u6 dovecot-managesieved 1:2.3.4.1-5+deb10u6 dovecot-mysql 1:2.3.4.1-5+deb10u6 dovecot-sieve 1:2.3.4.1-5+deb10u6 root@nmail:/etc/dovecot/sieve# cat before.sieve # Sieve rules that are run before the user's filters. # Messages flagged as spam are moved into the Junk folder. require [ "fileinto", "mailbox" ]; if header :contains "X-Spam-Flag" "YES" { fileinto :create "INBOX.Junk"; stop; } -- already executed # sieve before.sieve -- service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { mode = 0600 user = postfix group = postfix } } -- root@nmail:/etc/dovecot/conf.d# <mailto:root@nmail:/etc/dovecot/conf.d> cat 90-sieve.conf ## ## Settings for the Sieve interpreter ## plugin { # The path to the user's main active script. If ManageSieve is used, this the # location of the symbolic link controlled by ManageSieve. # sieve = ~/sieve/.dovecot.sieve sieve = file:%h/sieve;active=%h/.dovecot.sieve # Directory for :personal include scripts for the include extension. This # is also where the ManageSieve service stores the user's scripts. sieve_dir = ~/sieve # Path to a script file or a directory containing script files that need to be # executed before the user's script. If the path points to a directory, all # the Sieve scripts contained therein (with the proper .sieve extension) are # executed. The order of execution within a directory is determined by the # file names, using a normal 8bit per-character comparison. Multiple script # file or directory paths can be specified by appending an increasing number. sieve_before = /etc/dovecot/sieve/before.sieve } -- root@nmail:/etc/dovecot# doveconf -n # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.4 () # OS: Linux 4.19.0-16-amd64 x86_64 Debian 10.9 # Hostname: nmail.caloro.ch auth_mechanisms = plain login auth_verbose = yes info_log_path = /var/log/mail.log log_timestamp = %b %d %H:%M:%S Dovecot/ mail_access_groups = vmail mail_location = maildir:~/Maildir managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } plugin { sieve = ~/sieve/.dovecot.sieve sieve_dir = ~/sieve } postmaster_address = mca(a)caloro.ch <mailto:mca@caloro.ch> protocols = imap lmtp sieve service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } unix_listener auth-client { mode = 0660 user = mail } } service imap-login { inet_listener imap { port = 0 } inet_listener imaps { port = 993 ssl = yes } } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0600 user = postfix } } service stats { unix_listener stats-reader { group = vmail mode = 0666 user = vmail } unix_listener stats-writer { group = vmail mode = 0666 user = vmail } } ssl = required ssl_cert = </etc/letsencrypt/live/nmail.caloro.ch/fullchain.pem ssl_cipher_list = ECDHE-RSA-CHACHA20-POLY1305:ALL:!LOW:!SSLv2:!EXP:!aNULL ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it ssl_min_protocol = TLSv1.2 userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } protocol lda { mail_plugins = " quota sieve" } protocol imap { mail_plugins = " quota imap_quota" ssl_cert = </etc/letsencrypt/live/nmail.caloro.ch/fullchain.pem ssl_key = # hidden, use -P to show it } protocol lmtp { mail_plugins = " sieve" } Mauri

1 0

sieve filter bevor.spam, arnt take effect
by mauric＠gmx.ch 12 Apr '21

12 Apr '21

Hello Please willing to filter "bevor spam" mail... filtering arnt take effect .. please i dont see the mistake. Thanks for any possible update. Debian buster -- root@nmail:/etc/dovecot# dpkg -l | grep dovecot dovecot-core 1:2.3.4.1-5+deb10u6 dovecot-imapd 1:2.3.4.1-5+deb10u6 dovecot-lmtpd 1:2.3.4.1-5+deb10u6 dovecot-managesieved 1:2.3.4.1-5+deb10u6 dovecot-mysql 1:2.3.4.1-5+deb10u6 dovecot-sieve 1:2.3.4.1-5+deb10u6 root@nmail:/etc/dovecot/sieve# cat before.sieve # Sieve rules that are run before the user's filters. # Messages flagged as spam are moved into the Junk folder. require [ "fileinto", "mailbox" ]; if header :contains "X-Spam-Flag" "YES" { fileinto :create "INBOX.Junk"; stop; } -- already executed # sieve before.sieve -- service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { mode = 0600 user = postfix group = postfix } } -- root@nmail:/etc/dovecot/conf.d# <mailto:root@nmail:/etc/dovecot/conf.d#> cat 90-sieve.conf ## ## Settings for the Sieve interpreter ## plugin { # The path to the user's main active script. If ManageSieve is used, this the # location of the symbolic link controlled by ManageSieve. # sieve = ~/sieve/.dovecot.sieve sieve = file:%h/sieve;active=%h/.dovecot.sieve # Directory for :personal include scripts for the include extension. This # is also where the ManageSieve service stores the user's scripts. sieve_dir = ~/sieve # Path to a script file or a directory containing script files that need to be # executed before the user's script. If the path points to a directory, all # the Sieve scripts contained therein (with the proper .sieve extension) are # executed. The order of execution within a directory is determined by the # file names, using a normal 8bit per-character comparison. Multiple script # file or directory paths can be specified by appending an increasing number. sieve_before = /etc/dovecot/sieve/before.sieve } -- root@nmail:/etc/dovecot# doveconf -n # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.4 () # OS: Linux 4.19.0-16-amd64 x86_64 Debian 10.9 # Hostname: nmail.caloro.ch auth_mechanisms = plain login auth_verbose = yes info_log_path = /var/log/mail.log log_timestamp = %b %d %H:%M:%S Dovecot/ mail_access_groups = vmail mail_location = maildir:~/Maildir managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } plugin { sieve = ~/sieve/.dovecot.sieve sieve_dir = ~/sieve } postmaster_address = mca(a)caloro.ch <mailto:mca@caloro.ch> protocols = imap lmtp sieve service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } unix_listener auth-client { mode = 0660 user = mail } } service imap-login { inet_listener imap { port = 0 } inet_listener imaps { port = 993 ssl = yes } } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0600 user = postfix } } service stats { unix_listener stats-reader { group = vmail mode = 0666 user = vmail } unix_listener stats-writer { group = vmail mode = 0666 user = vmail } } ssl = required ssl_cert = </etc/letsencrypt/live/nmail.caloro.ch/fullchain.pem ssl_cipher_list = ECDHE-RSA-CHACHA20-POLY1305:ALL:!LOW:!SSLv2:!EXP:!aNULL ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it ssl_min_protocol = TLSv1.2 userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } protocol lda { mail_plugins = " quota sieve" } protocol imap { mail_plugins = " quota imap_quota" ssl_cert = </etc/letsencrypt/live/nmail.caloro.ch/fullchain.pem ssl_key = # hidden, use -P to show it } protocol lmtp { mail_plugins = " sieve" } Mauri

1 0

Sieve doesn't work after LTMP Director implementation
by Gonzalo Palacios Goicolea 12 Apr '21

12 Apr '21

Hi All, We're running dovecot director por proxying imap/pop queries to the backends. Yesterday we add LMTP proxying and it works fine, but we have realized that Sieve filters are no longer working after this change. Is it mandatory to add some config to the directors or backends after implementing LMTP through Director? We use dovecot-pigeonhole-2.2.36-8.el7.x86_64 dovecot-2.2.36-8.el7.x86_64 This is director servers config, if you also need backends config, please let me know doveconf -n # 2.2.36 (1f10bfa63): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.24 (124e06aa) # OS: Linux 3.10.0-1160.15.2.el7.x86_64 x86_64 Red Hat Enterprise Linux Server release 7.9 (Maipo) # Hostname: hidden auth_cache_negative_ttl = 5 mins auth_cache_size = 64 M auth_cache_ttl = 5 mins auth_failure_delay = 5 secs auth_verbose = yes default_client_limit = 40000 default_process_limit = 5500 director_mail_servers = Hidden director_servers = Hidden disable_plaintext_auth = no doveadm_port = 24245 listen = * lmtp_proxy = yes mail_location = maildir:%h/Maildir managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext mbox_write_locks = fcntl namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = proxy=y nopassword=y driver = static } plugin { mail_log_events = delete undelete expunge mailbox_delete mailbox_rename mailbox_create save mail_log_fields = uid box msgid from subject sieve = file:~/sieve;active=~/.dovecot.sieve } service director { fifo_listener login/proxy-notify { mode = 0666 user = $default_login_user } inet_listener { port = 9090 } unix_listener director-userdb { mode = 0600 } unix_listener login/director { mode = 0666 } } service doveadm { inet_listener { port = 24245 } } service imap-login { executable = imap-login director } service ipc { unix_listener ipc { user = dovecot } } service lmtp { inet_listener lmtp { address = x.x.x.x port = 24 } } service managesieve-login { executable = managesieve-login director } service pop3-login { executable = pop3-login director } ssl = no ssl_cert = </etc/pki/dovecot/certs/dovecot.pem ssl_key = # hidden, use -P to show it syslog_facility = local1 protocol lmtp { auth_socket_path = director-userdb } protocol doveadm { auth_socket_path = director-userdb } local 10.10.10.0/24 { doveadm_password = # hidden, use -P to show it } Thanks in advance and best regards -- *Gonzalo Palacios Goicolea* U.T de Infraestructura de Equipos Centrales /Tecnologías de la Información/ Universidad Autónoma de Madrid • Campus de Cantoblanco Antes de imprimir este correo piense si es necesario.Cuidemos el medioambiente.

2 1

Letsencrypt/OpenSSL test - Verify return code: 21
by B Shea 11 Apr '21

11 Apr '21

OS: Ubuntu 20.04.2 (on mutli-core VM) Dovecot (Ubuntu default/repo version): 2.3.7.2 (3c910f64b) OpenSSL (Ubuntu default/repo version): 1.1.1f 31 Mar 2020 Reproducing- Run: "openssl s_client -showcerts -connect imap.example.com:993 -servername imap.example.com" (using a diff domain obviously) Produces error: "Verify return code: 21 (unable to verify the first certificate)" (Meaning it is missing a CA verify from what I understand?) The "Verify return code: 21" error ONLY came to my attention after I had a customer complain about adding an email account to an Android phone (using the Google/Gmail default email app). -> "Certificate cannot be trusted" was shown by app when verifying imap connection. I could force it to be used, but this still bothered me, obviously. *The same certificate bundle is also used by smtp/postifx and www/nginx and works just fine. Also the openssl test shows 'verified' on both* I am posting to list mainly because on an older version of Dovecot I have running (default repo version for Ubuntu 18), I do not have this problem shown during testing with openssl. I did not have to change the ssl_cert or ssl_ca value in config. It has identical local.conf settings other than that. Granted it is also an older openssl version, too. So, I feel this may be a bug with Dovecot (or possibly OpenSSL). I finally 'fixed' it myself by using the LE 'fullchain.pem' certificate as the location for the 'ssl_cert' entry (and chain.pem for the ca entry). Previously, it was using the normal cert.pem file location. This is still the way it's setup on the other older machine and still works fine. Changes- |ssl_ca = </etc/letsencrypt/live/{CertName}/chain.pem (or 'fullchain.pem' should work) *ssl_cert = </etc/letsencrypt/live/{CertName}/fullchain.pem* (was 'cert.pem' previously) ssl_key = </etc/letsencrypt/live/{CertName}/privkey.pem| You can also view the problem here for more info : https://superuser.com/a/1640778/47628 Thanks ahead for any insight into this..

3 4

Debug: SSL_get_servername() failed
by Rowan ＠ Jetboy 10 Apr '21

10 Apr '21

I've setup Postfix to Dovecot LMTP delivery with mandatory TLS. Emails are being delivered with TLSv1.3 with no errors. However, setting: verbose_ssl = yes exposes this on each connection: lmtp(405619): Debug: SSL_get_servername() failed What it this mean, and what should I do about it?

2 1

How to prevent, or change priority, of dovecot's FAILed relay-submission to relay's IPv6 address, and submit ONLY/first to IPv4?
by PGNet Dev 09 Apr '21

09 Apr '21

my server is a linux, dual-stack IPv4/IPv6 host it runs multiple services, including, but not limited to, postfix & dovecot the hostname is internal.mx.example.com its DNS config, host internal.mx.example.com internal.mx.example.com has address 10.1.1.15 internal.mx.example.com has IPv6 address fd80:10:1::15 internal.mx.example.com mail is handled by 5 internal.mx.example.com. here, for dovecot dovecot --version 2.3.13 (89f716dc2) submission is configured to relay to the same-host postfix instance, listening @ port 465 ./conf.d/10-master.conf ... protocols = imap submission lmtp sieve ... submission_relay_host = internal.mx.example.com submission_relay_port = 465 submission_relay_ssl = smtps submission_relay_ssl_verify = yes submission_relay_trusted = yes whereas other services listen at both IPv4 & IPv6 addresses, with IPv6 preferred over IPv4, postfix listens ONLY on IPv4, postconf inet_protocols inet_protocols = ipv4 and, as intended, simply refuses ipv6 connections telnet 10.1.1.15 465 Trying 10.1.1.15... Connected to 10.1.1.15. Escape character is '^]'. ^] telnet> quit Connection closed. telnet -6 fd80:10:1::15 465 Trying fd80:10:1::15... telnet: connect to address fd80:10:1::15: Connection refused on each/every mail submit -- via dovecot -- dovecot makes the connection 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-server: conn 10.1.2.163:35388 [1]: Server accepted connection (fd=7) 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-server: conn 10.1.2.163:35388 [1]: Connection created 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 [1]: Connection created 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 [1]: Disconnected looks up IP address 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 [1]: Looking up IP address 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 [1]: Performing asynchronous DNS lookup 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-server: conn 10.1.2.163:35388 [1]: Sent: 235 2.7.0 Logged in. finds BOTH IPs -- IPv4 & IPv6 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 [1]: DNS lookup successful; got 2 IPs then first tries to connect via the host's IPv6 address, 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 [1]: Connecting to fd80:10:1::15:465 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 ([fd80:10:1::15]:465) [1]: Connecting 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 ([fd80:10:1::15]:465) [1]: Waiting for connect (fd=8) to finish for max 0 msecs ############ FAILS ############ 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 ([fd80:10:1::15]:465) [1]: Client connection failed (fd=8) then proceeds to connect to the host's IPv4 address 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 ([fd80:10:1::15]:465) [1]: Connecting to 10.1.1.15:465 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 (10.1.1.15:465) [1]: Connecting 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 (10.1.1.15:465) [1]: Waiting for connect (fd=11) to finish for max 0 msecs 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 (10.1.1.15:465) [1]: Client connected (fd=11) 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 (10.1.1.15:465) [1]: Connected to server (from 10.1.1.15:52880) 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 (10.1.1.15:465) [1]: Starting SSL handshake 2021-04-03 19:35:35 submission(mailer(a)mx.example.com)</tnO6xm/PIqsHgsH>: Debug: smtp-client: conn internal.mx.example.com:465 (10.1.1.15:465) [1]: SSL handshake successful ... and submission continues/completes I need to get Dovecot to stop trying/failing @ those IPv6 address submission connections. Either by (1) trying IPv4 *first*, before IPv6, to avoid the FAIL on submission or (2) turning off submission relay by IPv6 altogether, as I'll never use it What's the config required to do either/both?

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