Hello,

Am 29.05.2018 um 09:22 schrieb Aki Tuomi:

On 29.05.2018 09:54, Hajo Locke wrote:

...

Hello List,

i use dovecot 2.2.22 and have the same problem described here: https://dovecot.org/pipermail/dovecot/2017-November/110020.html

I can confirm that sometimes there is a problem with connection to mysql-db, but sometimes not. Reasons for failing are still under investigation by my mates.

My current main problem is, that this fail seems to be a one way ticket for dovecot. Even if mysql is verifyable working again and waiting for connection dovecot stucks furthermore with errors like this:

May 29 07:00:49 hostname dovecot: auth: Error: plain(mail@example.com,xxx.xxx.xx.xxx,<HGI4FVFt2Oy80j3P>): Request 999.7 timed out after 150 secs, state=1

When restarting dovecot all is immediately working again. Is there a way to tell dovecot to restart auth services or reinitialize mysql-connection after these hard fails? I could insert "idle_kill = 1 mins" into service auth and service auth-worker, but i dont know if this would work. Unfortunately i am not able to reproduce this error and there are always a couple of days between errors.

Thanks, Hajo

Hi!

I was not able to repeat this problem using 2.2.36. Can you provide steps to reproduce?

May 29 10:20:24 auth: Debug: client in: AUTH    1    PLAIN service=imap    secured    session=XtpgEVNtQeUAAAAAAAAAAAAAAAAAAAAB lip=::1    rip=::1    lport=143    rport=58689    resp=<hidden> May 29 10:20:24 auth-worker(31098): Debug: sql(test@domain.org,::1,<XtpgEVNtQeUAAAAAAAAAAAAAAAAAAAAB>): query: SELECT userid AS username, domain, password FROM users WHERE userid = 'test' AND domain = 'domain.org' May 29 10:20:54 auth-worker(31098): Warning: mysql: Query failed, retrying: Lost connection to MySQL server during query (idled for 28 secs) May 29 10:20:59 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 5 seconds before retry May 29 10:21:04 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 5 seconds before retry May 29 10:21:14 auth: Debug: auth client connected (pid=31134) May 29 10:21:14 imap-login: Warning: Growing pool 'imap login commands' with: 1024 May 29 10:21:14 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 25 seconds before retry

This is what it looks like for me and after restoring connectivity, it started working normally.

Unfortunately i can not reproduce. Servers running well for days or sometimes weeks and then it happens one time. I can provide some more logs.

This is an error with mysql involvement:

May 29 06:56:59 hostname dovecot: auth-worker(1099): Error: mysql(xx.xx.xx.xx): Connect failed to database (mysql): Can't connect to MySQL server on 'xx.xx.xx.xx' (111) - waiting for 1 seconds before retry . . some more of above line . May 29 06:56:59 hostname dovecot: auth-worker(1110): Error: sql(mail@example.com,xx.xx.xx.xx): Password query failed: Not connected to database May 29 06:56:59 hostname dovecot: auth: Error: auth worker: Aborted PASSV request for mail@example.com: Internal auth worker failure May 29 06:57:59 hostname dovecot: auth-worker(1099): Error: mysql: Query timed out (no free connections for 60 secs): SELECT inbox as user, password FROM mail_users WHERE login = 'username' AND active='Y' May 29 06:59:30 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<jc9yEFFtXcJXmx0F>): Request 999.2 timed out after 151 secs, state=1 . . much more of these lines with Request timed out .

At this point my mates restartet dovecot and all worked well immediately. Mysql performed a short restart at 6:56 and dovecot was not able to reconnect for about 10 mins until my mates did the restart. I could not reproduce the problem by manually restarting of mysql, this worked well.

This is an error without visible mysql involvement: . . lines of normal imap/pop activity . May 29 05:43:03 hostname dovecot: imap-login: Error: master(imap): Auth request timed out (received 0/12 bytes) May 29 05:43:03 hostname dovecot: imap-login: Internal login failure (pid=1014 id=16814) (internal failure, 1 successful auths): user=<username>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS May 29 05:43:03 hostname dovecot: imap: Error: Login client disconnected too early May 29 05:44:03 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<Wry1AlBt7couU7FV>): Request 1014.16815 timed out after 150 secs, state=1 May 29 05:44:08 hostname dovecot: imap: Error: Auth server request timed out after 155 secs (client-pid=1014 client-id=16814) May 29 05:44:33 hostname dovecot: imap-login: Disconnected: Inactivity during authentication (disconnected while authenticating, waited 180 secs): user=<>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS: Disconnected May 29 05:46:07 hostname dovecot: auth: Error: plain(mail@example.com,xx.xx.xx.xx,<j2cWClBtVf3Z+t+p>): Request 1014.16819 timed out after 150 secs, state=1 . . and so on until restart .

There is no errorlog in relation to mysql written by dovecot.

We use 2.2.22 because this version is provided with Ubuntu 16.04 and Ubuntu Team is maintaining software and providing security patches, which happens 2017 and 2018 a couple of times. By manually compiling and using newer versions you have to check updates by yourself and you are forced to run every single update. Our goal is reliability which contradicts to use of bleeding edge software.

This is output of current doveconf -n

# 2.2.22 (fe789d2): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.13 (7b14904) # OS: Linux 4.4.0-127-generic x86_64 Ubuntu 16.04.4 LTS auth_mechanisms = plain login auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@üÜöÖäÄ auth_worker_max_count = 60 disable_plaintext_auth = no imap_capability = +XLIST lock_method = flock login_greeting = mailserver ready. login_log_format_elements = user=<%u> method=%m rip=%r lip=%l %c mail_cache_min_mail_count = 30 mail_location = mbox:~/mail:INBOX=/var/mail/%u mail_max_userip_connections = 30 mbox_read_locks = dotlock mbox_very_dirty_syncs = yes namespace inbox { inbox = yes location = mailbox Archiv { auto = no special_use = } mailbox Drafts { auto = no special_use = } mailbox Junk { auto = no special_use = } mailbox Sent { auto = no special_use = } mailbox Trash { auto = no special_use = } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf driver = sql } protocols = imap pop3 service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } user = root } service imap-login { executable = /usr/lib/dovecot/imap-login process_min_avail = 1 service_count = 0 user = dovecot } service imap { process_limit = 1024 } service pop3-login { executable = /usr/lib/dovecot/pop3-login process_min_avail = 1 service_count = 0 user = dovecot } service pop3 { executable = /usr/lib/dovecot/pop3 process_limit = 1024 } shutdown_clients = no ssl_ca = </path/path/cert.pem ssl_cert = </path/path/cert.pem ssl_cipher_list = ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:!DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA ssl_dh_parameters_length = 2048 ssl_key = </path/path/cert.pem ssl_prefer_server_ciphers = yes ssl_protocols = !SSLv2 !SSLv3 userdb { args = /etc/dovecot/dovecot-sql.conf driver = sql } verbose_proctitle = yes protocol imap { imap_client_workarounds = delay-newmail mail_plugins = mail_log notify ssl = yes } protocol pop3 { pop3_client_workarounds = oe-ns-eoh outlook-no-nuls pop3_no_flag_updates = no pop3_uidl_format = %08Xu%08Xv ssl = yes }

I hope you have some hints. I dislike to monitor this with fail2ban and do hard restarts.

Aki

Thanks, Hajo

Am 29.05.2018 um 11:00 schrieb Aki Tuomi <aki.tuomi@dovecot.fi>:

On 29.05.2018 11:35, Hajo Locke wrote:

...

Hello,

Am 29.05.2018 um 09:22 schrieb Aki Tuomi:

...

On 29.05.2018 09:54, Hajo Locke wrote:

...

Hello List,

i use dovecot 2.2.22 and have the same problem described here: https://dovecot.org/pipermail/dovecot/2017-November/110020.html

I can confirm that sometimes there is a problem with connection to mysql-db, but sometimes not. Reasons for failing are still under investigation by my mates.

My current main problem is, that this fail seems to be a one way ticket for dovecot. Even if mysql is verifyable working again and waiting for connection dovecot stucks furthermore with errors like this:

May 29 07:00:49 hostname dovecot: auth: Error: plain(mail@example.com,xxx.xxx.xx.xxx,<HGI4FVFt2Oy80j3P>): Request 999.7 timed out after 150 secs, state=1

When restarting dovecot all is immediately working again. Is there a way to tell dovecot to restart auth services or reinitialize mysql-connection after these hard fails? I could insert "idle_kill = 1 mins" into service auth and service auth-worker, but i dont know if this would work. Unfortunately i am not able to reproduce this error and there are always a couple of days between errors.

Thanks, Hajo

Hi!

I was not able to repeat this problem using 2.2.36. Can you provide steps to reproduce?

May 29 10:20:24 auth: Debug: client in: AUTH 1 PLAIN service=imap secured session=XtpgEVNtQeUAAAAAAAAAAAAAAAAAAAAB lip=::1 rip=::1 lport=143 rport=58689 resp=<hidden> May 29 10:20:24 auth-worker(31098): Debug: sql(test@domain.org,::1,<XtpgEVNtQeUAAAAAAAAAAAAAAAAAAAAB>): query: SELECT userid AS username, domain, password FROM users WHERE userid = 'test' AND domain = 'domain.org' May 29 10:20:54 auth-worker(31098): Warning: mysql: Query failed, retrying: Lost connection to MySQL server during query (idled for 28 secs) May 29 10:20:59 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 5 seconds before retry May 29 10:21:04 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 5 seconds before retry May 29 10:21:14 auth: Debug: auth client connected (pid=31134) May 29 10:21:14 imap-login: Warning: Growing pool 'imap login commands' with: 1024 May 29 10:21:14 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 25 seconds before retry

This is what it looks like for me and after restoring connectivity, it started working normally.

Unfortunately i can not reproduce. Servers running well for days or sometimes weeks and then it happens one time. I can provide some more logs.

This is an error with mysql involvement:

May 29 06:56:59 hostname dovecot: auth-worker(1099): Error: mysql(xx.xx.xx.xx): Connect failed to database (mysql): Can't connect to MySQL server on 'xx.xx.xx.xx' (111) - waiting for 1 seconds before retry . . some more of above line . May 29 06:56:59 hostname dovecot: auth-worker(1110): Error: sql(mail@example.com,xx.xx.xx.xx): Password query failed: Not connected to database May 29 06:56:59 hostname dovecot: auth: Error: auth worker: Aborted PASSV request for mail@example.com: Internal auth worker failure May 29 06:57:59 hostname dovecot: auth-worker(1099): Error: mysql: Query timed out (no free connections for 60 secs): SELECT inbox as user, password FROM mail_users WHERE login = 'username' AND active='Y' May 29 06:59:30 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<jc9yEFFtXcJXmx0F>): Request 999.2 timed out after 151 secs, state=1 . . much more of these lines with Request timed out .

At this point my mates restartet dovecot and all worked well immediately. Mysql performed a short restart at 6:56 and dovecot was not able to reconnect for about 10 mins until my mates did the restart. I could not reproduce the problem by manually restarting of mysql, this worked well.

This is an error without visible mysql involvement: . . lines of normal imap/pop activity . May 29 05:43:03 hostname dovecot: imap-login: Error: master(imap): Auth request timed out (received 0/12 bytes) May 29 05:43:03 hostname dovecot: imap-login: Internal login failure (pid=1014 id=16814) (internal failure, 1 successful auths): user=<username>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS May 29 05:43:03 hostname dovecot: imap: Error: Login client disconnected too early May 29 05:44:03 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<Wry1AlBt7couU7FV>): Request 1014.16815 timed out after 150 secs, state=1 May 29 05:44:08 hostname dovecot: imap: Error: Auth server request timed out after 155 secs (client-pid=1014 client-id=16814) May 29 05:44:33 hostname dovecot: imap-login: Disconnected: Inactivity during authentication (disconnected while authenticating, waited 180 secs): user=<>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS: Disconnected May 29 05:46:07 hostname dovecot: auth: Error: plain(mail@example.com,xx.xx.xx.xx,<j2cWClBtVf3Z+t+p>): Request 1014.16819 timed out after 150 secs, state=1 . . and so on until restart .

There is no errorlog in relation to mysql written by dovecot.

We use 2.2.22 because this version is provided with Ubuntu 16.04 and Ubuntu Team is maintaining software and providing security patches, which happens 2017 and 2018 a couple of times. By manually compiling and using newer versions you have to check updates by yourself and you are forced to run every single update. Our goal is reliability which contradicts to use of bleeding edge software.

This is output of current doveconf -n

# 2.2.22 (fe789d2): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.13 (7b14904) # OS: Linux 4.4.0-127-generic x86_64 Ubuntu 16.04.4 LTS auth_mechanisms = plain login auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@üÜöÖäÄ auth_worker_max_count = 60 disable_plaintext_auth = no imap_capability = +XLIST lock_method = flock login_greeting = mailserver ready. login_log_format_elements = user=<%u> method=%m rip=%r lip=%l %c mail_cache_min_mail_count = 30 mail_location = mbox:~/mail:INBOX=/var/mail/%u mail_max_userip_connections = 30 mbox_read_locks = dotlock mbox_very_dirty_syncs = yes namespace inbox { inbox = yes location = mailbox Archiv { auto = no special_use = } mailbox Drafts { auto = no special_use = } mailbox Junk { auto = no special_use = } mailbox Sent { auto = no special_use = } mailbox Trash { auto = no special_use = } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf driver = sql } protocols = imap pop3 service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } user = root } service imap-login { executable = /usr/lib/dovecot/imap-login process_min_avail = 1 service_count = 0 user = dovecot } service imap { process_limit = 1024 } service pop3-login { executable = /usr/lib/dovecot/pop3-login process_min_avail = 1 service_count = 0 user = dovecot } service pop3 { executable = /usr/lib/dovecot/pop3 process_limit = 1024 } shutdown_clients = no ssl_ca = </path/path/cert.pem ssl_cert = </path/path/cert.pem ssl_cipher_list = ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:!DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA ssl_dh_parameters_length = 2048 ssl_key = </path/path/cert.pem ssl_prefer_server_ciphers = yes ssl_protocols = !SSLv2 !SSLv3 userdb { args = /etc/dovecot/dovecot-sql.conf driver = sql } verbose_proctitle = yes protocol imap { imap_client_workarounds = delay-newmail mail_plugins = mail_log notify ssl = yes } protocol pop3 { pop3_client_workarounds = oe-ns-eoh outlook-no-nuls pop3_no_flag_updates = no pop3_uidl_format = %08Xu%08Xv ssl = yes }

I hope you have some hints. I dislike to monitor this with fail2ban and do hard restarts.

...

Aki

Thanks, Hajo

Can you try doing successful auth MySQL, then, for short while, blocking access to MySQL server using iptables (no idea how to do this with socket based), and try authenticating while access is blocked. It should, hopefully, reproduce this error.

You could try to remove the socket file when mysql is running and then using socat:

socat UNIX-LISTEN:/var/lib/mysql/mysql.sock,fork,reuseaddr,unlink-early,mode=777 TCP:127.0.0.1:3306

Best regards Gerald

Hi,

We've experienced this too, happens once in a few months i'm reply-ing now because it happend this morning on one of our multiple nodes, other nodes were fine.

debian 9.4 dovecot-core 1:2.2.34-2~bpo9+1

Feb 1 06:24:58 machine61 dovecot: auth: Error: plain(EDITED@EDITED.nl,10.0.10.182,<zHU8VM6ATrIKAAq2>): Request 890.37948303 timed out after 150 secs, state=1

Restart of the daemon fixed it. unable to reproduce.

I'm willing to enable specific debug options to help debug this. if you could point me in the correct settings for the dovecot: auth: daemon.

On Wed, May 30, 2018 at 3:32 PM Hajo Locke <Hajo.Locke@gmx.de> wrote:

Hello,

Am 29.05.2018 um 11:30 schrieb Gerald Galster:

...

...

Am 29.05.2018 um 11:00 schrieb Aki Tuomi <aki.tuomi@dovecot.fi>:

On 29.05.2018 11:35, Hajo Locke wrote:

...

Hello,

Am 29.05.2018 um 09:22 schrieb Aki Tuomi:

...

On 29.05.2018 09:54, Hajo Locke wrote:

...

Hello List,

i use dovecot 2.2.22 and have the same problem described here: https://dovecot.org/pipermail/dovecot/2017-November/110020.html

I can confirm that sometimes there is a problem with connection to mysql-db, but sometimes not. Reasons for failing are still under investigation by my mates.

My current main problem is, that this fail seems to be a one way ticket for dovecot. Even if mysql is verifyable working again and waiting for connection dovecot stucks furthermore with errors like this:

May 29 07:00:49 hostname dovecot: auth: Error: plain(mail@example.com,xxx.xxx.xx.xxx,<HGI4FVFt2Oy80j3P>): Request 999.7 timed out after 150 secs, state=1

When restarting dovecot all is immediately working again. Is there a way to tell dovecot to restart auth services or reinitialize mysql-connection after these hard fails? I could insert "idle_kill = 1 mins" into service auth and service auth-worker, but i dont know if this would work. Unfortunately i am not able to

reproduce

...

...

...

...

...

this error and there are always a couple of days between errors.

Thanks, Hajo

Hi!

I was not able to repeat this problem using 2.2.36. Can you provide steps to reproduce?

May 29 10:20:24 auth: Debug: client in: AUTH 1 PLAIN service=imap secured session=XtpgEVNtQeUAAAAAAAAAAAAAAAAAAAAB lip=::1 rip=::1 lport=143 rport=58689 resp=<hidden> May 29 10:20:24 auth-worker(31098): Debug: sql(test@domain.org,::1,<XtpgEVNtQeUAAAAAAAAAAAAAAAAAAAAB>): query: SELECT userid AS username, domain, password FROM users WHERE userid = 'test' AND domain = 'domain.org' May 29 10:20:54 auth-worker(31098): Warning: mysql: Query failed, retrying: Lost connection to MySQL server during query (idled for 28 secs) May 29 10:20:59 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 5 seconds before retry May 29 10:21:04 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 5 seconds before retry May 29 10:21:14 auth: Debug: auth client connected (pid=31134) May 29 10:21:14 imap-login: Warning: Growing pool 'imap login commands' with: 1024 May 29 10:21:14 auth-worker(31098): Error: mysql(127.0.0.1): Connect failed to database (dovecot): Can't connect to MySQL server on '127.0.0.1' (4) - waiting for 25 seconds before retry

This is what it looks like for me and after restoring connectivity, it started working normally. Unfortunately i can not reproduce. Servers running well for days or sometimes weeks and then it happens one time. I can provide some more logs.

This is an error with mysql involvement:

May 29 06:56:59 hostname dovecot: auth-worker(1099): Error: mysql(xx.xx.xx.xx): Connect failed to database (mysql): Can't connect to MySQL server on 'xx.xx.xx.xx' (111) - waiting for 1 seconds before retry . . some more of above line . May 29 06:56:59 hostname dovecot: auth-worker(1110): Error: sql(mail@example.com,xx.xx.xx.xx): Password query failed: Not connected to database May 29 06:56:59 hostname dovecot: auth: Error: auth worker: Aborted PASSV request for mail@example.com: Internal auth worker failure May 29 06:57:59 hostname dovecot: auth-worker(1099): Error: mysql: Query timed out (no free connections for 60 secs): SELECT inbox as user, password FROM mail_users WHERE login = 'username' AND active='Y' May 29 06:59:30 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<jc9yEFFtXcJXmx0F>): Request 999.2 timed out after 151 secs, state=1 . . much more of these lines with Request timed out .

At this point my mates restartet dovecot and all worked well immediately. Mysql performed a short restart at 6:56 and dovecot was not able to reconnect for about 10 mins until my mates did the restart. I could not reproduce the problem by manually restarting of mysql, this worked well.

This is an error without visible mysql involvement: . . lines of normal imap/pop activity . May 29 05:43:03 hostname dovecot: imap-login: Error: master(imap): Auth request timed out (received 0/12 bytes) May 29 05:43:03 hostname dovecot: imap-login: Internal login failure (pid=1014 id=16814) (internal failure, 1 successful auths): user=<username>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS May 29 05:43:03 hostname dovecot: imap: Error: Login client disconnected too early May 29 05:44:03 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<Wry1AlBt7couU7FV>): Request 1014.16815 timed out after 150 secs, state=1 May 29 05:44:08 hostname dovecot: imap: Error: Auth server request timed out after 155 secs (client-pid=1014 client-id=16814) May 29 05:44:33 hostname dovecot: imap-login: Disconnected: Inactivity during authentication (disconnected while authenticating, waited 180 secs): user=<>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS: Disconnected May 29 05:46:07 hostname dovecot: auth: Error: plain(mail@example.com,xx.xx.xx.xx,<j2cWClBtVf3Z+t+p>): Request 1014.16819 timed out after 150 secs, state=1 . . and so on until restart .

There is no errorlog in relation to mysql written by dovecot.

We use 2.2.22 because this version is provided with Ubuntu 16.04 and Ubuntu Team is maintaining software and providing security patches, which happens 2017 and 2018 a couple of times. By manually compiling and using newer versions you have to check updates by yourself and you are forced to run every single update. Our goal is reliability which contradicts to use of bleeding edge software.

This is output of current doveconf -n

# 2.2.22 (fe789d2): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.13 (7b14904) # OS: Linux 4.4.0-127-generic x86_64 Ubuntu 16.04.4 LTS auth_mechanisms = plain login auth_username_chars =

abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@üÜöÖäÄ

...

auth_worker_max_count = 60 disable_plaintext_auth = no imap_capability = +XLIST lock_method = flock login_greeting = mailserver ready. login_log_format_elements = user=<%u> method=%m rip=%r lip=%l %c mail_cache_min_mail_count = 30 mail_location = mbox:~/mail:INBOX=/var/mail/%u mail_max_userip_connections = 30 mbox_read_locks = dotlock mbox_very_dirty_syncs = yes namespace inbox { inbox = yes location = mailbox Archiv { auto = no special_use = } mailbox Drafts { auto = no special_use = } mailbox Junk { auto = no special_use = } mailbox Sent { auto = no special_use = } mailbox Trash { auto = no special_use = } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf driver = sql } protocols = imap pop3 service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } user = root } service imap-login { executable = /usr/lib/dovecot/imap-login process_min_avail = 1 service_count = 0 user = dovecot } service imap { process_limit = 1024 } service pop3-login { executable = /usr/lib/dovecot/pop3-login process_min_avail = 1 service_count = 0 user = dovecot } service pop3 { executable = /usr/lib/dovecot/pop3 process_limit = 1024 } shutdown_clients = no ssl_ca = </path/path/cert.pem ssl_cert = </path/path/cert.pem ssl_cipher_list =

ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:!DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA

...

ssl_dh_parameters_length = 2048 ssl_key = </path/path/cert.pem ssl_prefer_server_ciphers = yes ssl_protocols = !SSLv2 !SSLv3 userdb { args = /etc/dovecot/dovecot-sql.conf driver = sql } verbose_proctitle = yes protocol imap { imap_client_workarounds = delay-newmail mail_plugins = mail_log notify ssl = yes } protocol pop3 { pop3_client_workarounds = oe-ns-eoh outlook-no-nuls pop3_no_flag_updates = no pop3_uidl_format = %08Xu%08Xv ssl = yes }

I hope you have some hints. I dislike to monitor this with fail2ban and do hard restarts.

...

Aki

Thanks, Hajo Can you try doing successful auth MySQL, then, for short while, blocking access to MySQL server using iptables (no idea how to do this with socket based), and try authenticating while access is blocked. It should, hopefully, reproduce this error. You could try to remove the socket file when mysql is running and then using socat:

socat UNIX-LISTEN:/var/lib/mysql/mysql.sock,fork,reuseaddr,unlink-early,mode=777 TCP:127.0.0.1:3306

Best regards Gerald

Thanks for your help. Unfortunately iam not able to reproduce this manually. Bei blocking port with iptables or manipulating the socket dovecot always log correctly the disconnection. After unblock port or reestablishing the socket dovecot reconnects succsessful and auth works immediately. I think my report must have other nature of invalid connection/bug.

A few minutes ago i noticed one server having this problem. dovecot was logging just lines about timed out connections but in parallel i was able to connect to local mysql and run userdb/passdb queries.

It starts like this:

May 30 14:51:44 hostname dovecot: imap-login: Error: master(imap): Auth request timed out (received 0/12 bytes) May 30 14:51:44 hostname dovecot: imap-login: Internal login failure (pid=29595 id=1556) (internal failure, 1 successful auths): user=<username>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS May 30 14:51:44 hostname dovecot: imap: Error: Login client disconnected too early

After that only lines with error, timeouts or other fails:

May 30 14:52:44 hostname dovecot: auth: Error: plain(username,xx.xx.xx.xx,<3ObCymttnsZNu+bd>): Request 29595.1557 timed out after 150 secs, state=1 May 30 14:52:49 hostname dovecot: imap: Error: Auth server request timed out after 155 secs (client-pid=29595 client-id=1556) May 30 14:52:59 hostname dovecot: auth: Error: plain(mail@example.com,xx.xx.xx.xx,<dqOoy2ttm/pe2WEH>): Request 29595.1558 timed out after 150 secs, state=1 May 30 14:53:13 hostname dovecot: imap-login: Disconnected: Inactivity during authentication (disconnected while authenticating, waited 179 secs): user=<>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS: Disconnected

Unfortunately dovecot was not able to reestablish connection to local mysql. ps axu showed stack of jamed passdb queries:

root 1055 0.0 0.0 40984 6120 ? S Mai29 0:09 dovecot/auth [0 wait, 84 passdb, 1 userdb] root 9057 0.0 0.0 40084 5144 ? S 15:03 0:00 dovecot/auth [0 wait, 0 passdb, 0 userdb] root 11823 0.0 0.0 40084 5036 ? S 15:04 0:00 dovecot/auth [0 wait, 0 passdb, 0 userdb] root 12975 0.0 0.0 40084 5080 ? S 15:05 0:00 dovecot/auth worker: idling

By killing PID 1055 dovecot was spawning new auth process and normal processing startet again. Until restart no Login was possible for any user.

Other people reported limitproblems with systemd, but affected servers have no higher load than usual. Hmm, iam running out of ideas now.

Thanks, Hajo