February 2018 - dovecot

Nightly builds of Debian packages
by Christoph Pleger 24 Sep '18

24 Sep '18

Hello, how is the future of the automatically built nightly debian packages of dovecot? Has that project been ceased? The current auto-built version is still 2.2.28 from April 28, though 2.2.29 (with a security patch) of dovecot is out now for a while. Regards Christoph

4 3

auth_policy in a non-authenticating proxy chain
by Peter Mogensen 15 Sep '18

15 Sep '18

Hi, I was looking into the new Authentication Policy feature: https://wiki2.dovecot.org/Authentication/Policy I had kinda hoped that I would be able to enfore this in a proxy running in front of several backends. This proxy does not authenticate. It use "nopassword". But I realize that the "succes" reported in the final authpolicy req. (command=report) is not what is actaully happening on the IMAP protocol level, but rather the result of the passdb chain in the proxy. (I should probably have predicted this, it's kinda reasonable). However... since the proxy use "nopassword", ALL passdb lookups result in "success", so the proxy will never report an authentication failure to the authpolicy server. This, of course, forces me to do the authpolicy check on the backend with a shared state, but It would still have been nice to have the proxy being able to do the first "command=allow" req. and reject attemps already there even though the backend does "command=report". /Peter

3 4

Occasional crash in db-auth.c (Valgrind: Invalid read of size 4 et al.), Dovecot 2.2.27+
by Jonas Wielicki 14 Sep '18

14 Sep '18

Dear list, We are encountering troubles with dovecot using LDAP userdbs on Debian stretch (but if I’m reading valgrind correctly, we can reproduce this with vanilla dovecot master). Minimal reproducer below. While testing an upgrade to Debian stretch (dovecot-core=1:2.2.27-3+deb9u1), auth-worker has stopped working. We are using two LDAP user databases; one which is iterable, and one which is not (for reasons; I think this is not relevant; if it is, we’re happy to elaborate). The issue seems to be present in any LDAP userdb iteration handling, but it only seems to cause a crash in certain conditions which seem to be reproducibly caused by our setup for some reason. We’re seeing one of two errors. Variant A: Jan 27 13:40:05 up2 dovecot: auth-worker: Error: *** Error in `dovecot/auth': free(): corrupted unsorted chunks: 0x000056553f0fcfa0 *** Jan 27 13:40:05 up2 dovecot: auth-worker: Error: ======= Backtrace: ========= Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /lib/x86_64-linux-gnu/ libc.so.6(+0x70bcb)[0x7f78426adbcb] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /lib/x86_64-linux-gnu/ libc.so.6(+0x76f96)[0x7f78426b3f96] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /lib/x86_64-linux-gnu/ libc.so.6(+0x777de)[0x7f78426b47de] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /usr/lib/dovecot/modules/ auth/libauthdb_ldap.so(+0x5bde)[0x7f7842008bde] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /usr/lib/dovecot/ libdovecot.so.0(io_loop_call_io+0x52)[0x7f78430cfdd2] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /usr/lib/dovecot/ libdovecot.so.0(io_loop_handler_run_internal+0x109)[0x7f78430d1409] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /usr/lib/dovecot/ libdovecot.so.0(io_loop_handler_run+0x3c)[0x7f78430cfe6c] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /usr/lib/dovecot/ libdovecot.so.0(io_loop_run+0x38)[0x7f78430d0018] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /usr/lib/dovecot/ libdovecot.so.0(master_service_run+0x13)[0x7f7843057e93] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: dovecot/auth(main+0x398) [0x56553da45f98] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: /lib/x86_64-linux-gnu/ libc.so.6(__libc_start_main+0xf1)[0x7f784265d2b1] Jan 27 13:40:05 up2 dovecot: auth-worker: Error: dovecot/auth(_start+0x2a) [0x56553da461aa] Variant B: Jan 27 13:06:56 up2 dovecot: auth-worker(27495): Panic: file db-ldap.c: line 840 (db_ldap_result_unref): assertion failed: (res->refcount > 0) Jan 27 13:06:56 up2 dovecot: auth-worker(27495): Error: Raw backtrace: /usr/ lib/dovecot/libdovecot.so.0(+0x95272) [0x7f027a4fc272] -> /usr/lib/dovecot/ libdovecot.so.0(+0x9536d) [0x7f027a4fc36d] -> /usr/lib/dovecot/libdovecot.so. 0(i_fatal+0) [0x7f027a492951] -> /usr/lib/dovecot/modules/auth/ libauthdb_ldap.so(+0x3868) [0x7f0279447868] -> /usr/lib/dovecot/modules/auth/ libauthdb_ldap.so(+0x5d7c) [0x7f0279449d7c] -> /usr/lib/dovecot/libdovecot.so. 0(io_loop_call_io+0x52) [0x7f027a510dd2] -> /usr/lib/dovecot/libdovecot.so. 0(io_loop_handler_run_internal+0x109) [0x7f027a512409] -> /usr/lib/dovecot/ libdovecot.so.0(io_loop_handler_run+0x3c) [0x7f027a510e6c] -> /usr/lib/ dovecot/libdovecot.so.0(io_loop_run+0x38) [0x7f027a511018] -> /usr/lib/ dovecot/libdovecot.so.0(master_service_run+0x13) [0x7f027a498e93] -> dovecot/ auth(main+0x398) [0x55b981cd2f98] -> /lib/x86_64-linux-gnu/libc.so. 6(__libc_start_main+0xf1) [0x7f0279a9e2b1] -> dovecot/auth(_start+0x2a) [0x55b981cd31aa] When running auth-worker within valgrind, we get more information (valgrind extract from mail.log attached for two versions of dovecot). We have attached mail.log contents for the respective valgrind runs. This seems to affect at least 2.2.27 onwards. We can reproduce the crash with our production data 100% of the time. The valgrind error is present even with very minimal setups (see below). Unfortunately, I haven’t been able so far to create an LDAP database which produces the crash as reliable as our production database does (which we cannot share for obvious reasons). Minimal Reproducer of Valgrind error: - Install dovecot 2.2.27 from debian stretch, or compile from master. - Install valgrind - In conf.d/10-auth.conf, disable auth-system.conf.ext - In conf.d/10-auth.conf, enable auth-ldap.conf.ext - Set contents of dovecot-ldap.conf.ext to: hosts = localhost base = dc=nodomain - In conf.d/10-master.conf, in section "service auth-worker", set executable = /usr/bin/valgrind /usr/lib/dovecot/auth -w (path may differ on your system) - Install an LDAP server with a database for dc=nodomain; this is trivial to do with debian: Simply install slapd and systemctl start slapd. - Start dovecot - Run doveadm user '*' - You should find the error in the mail.log. I hope this is somehow useful to fix our crash issue. We’ll be happy to provide more information as needed. kind regards, Jonas

4 4

Status of SMTPUTF8?
by Noah Tilton 14 Sep '18

14 Sep '18

I was wondering whether there is a roadmap for adding SMTPUTF8 support to Dovecot? My delivery pattern is Postfix -> Dovecot LMTP and it is choking on utf8 messages. I might be able to volunteer some of my time as a developer. Another thread about this seemed to go unanswered: http://dovecot.org/list/dovecot/2016-September/105474.html http://unix.stackexchange.com/questions/320091/configure-postfix-and-doveco… -Noah

4 3

Set X-Original-To based an ORCPT?
by Peer Heinlein 09 Aug '18

09 Aug '18

Since http://dovecot.org/pipermail/dovecot-cvs/2014-November/025241.html Dovecot's LMTP does support ORCPT. Is it possible to set X-Original-To-Header based on that ORCPT? Peer -- Heinlein Support GmbH Schwedter Str. 8/9b, 10119 Berlin http://www.heinlein-support.de Tel: 030 / 405051-42 Fax: 030 / 405051-19 Zwangsangaben lt. §35a GmbHG: HRB 93818 B / Amtsgericht Berlin-Charlottenburg, Geschäftsführer: Peer Heinlein -- Sitz: Berlin

5 5

[Dovecot] quota-status not working in distributed environment
by Benoit Panizzon 30 Jul '18

30 Jul '18

Hello List Quick overview of our set-up: Postfix / Dovecot (2.2.2.1) / MySQL Cluster on (at the moment) three Servers to create a HA environment where you could easily add additional servers as the demand or load grows. Circular dovecot replication is used so each server uses another one as replication partner and allowing one server to fail. Dovecot Proxy Feature being used, so we can use round-robin DNS and each server can forward the connecting user to the correct 'master' for his mailbox. So far, everything works as expected. Now we want to reject emails to 'full' mailboxes during SMTP to prevent backscatter and use the quota-status policy service from within postfix. That works fine, if the mailbox or it's replica is present on the machine where quota-status is called, but it fails if it's run on a machine where neither the mailbox or the replica is present. In our case, we get a correct SMTP 550 'Mailbox Full' Reject in two cases and a LMTP generated bounce in the later case. Also `doveadm quota get -u user(a)example.com` return the correct quota if run on the two machines which have the mailbox and it's copy locale, but return 0% used if run on the other machine. Is there a way to get quota-status to also use the proxy feature to request the quota information from the correct machine? Or is the postfix policy daemon call to the quota-status socket documented somewhere (it must be, but where?) so we could implement it from within the Milter? (we use the sendmail Milter API from postfix to filter spam and viruses, do sender/recipient rewriting, forward bounce matching, rate limmiting, login/IP statistics to block botnets abusing phished addresses and legal intercept stuff anyway) Kind regards Benoit Panizzon -- I m p r o W a r e A G - ______________________________________________________ Zurlindenstrasse 29 Tel +41 61 826 93 07 CH-4133 Pratteln Fax +41 61 826 93 02 Schweiz Web http://www.imp.ch ______________________________________________________

5 6

SIS: dovecot creates duplicated attachments (sometimes)
by Alexander Moisseev 20 Jul '18

20 Jul '18

SIS deduplication was broken in 2.2.16 and has been fixed with https://github.com/dovecot/core/commit/3b39022ea0513363241cf852b7d454c84158… but still sometimes (just several times in a month or so) dovecot creates duplicated attachments. As you can see in directory listings below all attachments was created at (about) the same time, but one of them has different inode number. It easy to discover using https://github.com/moisseev/doveadm-tools/blob/master/bin/dsisck # dsisck -n mail_uid=vmail mail_attachment_dir=/vmail/attachments ==> Checking SIS... # ln -f ./30/b3/30b367c584a123eee59478adf3e4f4c9e1226545-c56eae04a67c3157287f01003d96bafd ./30/b3/30b367c584a123eee59478adf3e4f4c9e1226545-7ad0a411d17c31572b7a01003d96bafd # mkdir -p -m 700 ./64/8f/hashes && ln ./64/8f/648f5cfa27af6d20c8570fdcaeab997663e15105-55430d2cd4432c571cb600003d96bafd ./64/8f/hashes/648f5cfa27af6d20c8570fdcaeab997663e15105 # ln -f ./6f/3f/6f3fa3e4d374a9c80d07af54960ce0e7adb2e0fe-b1935817ed753557546700003d96bafd ./6f/3f/6f3fa3e4d374a9c80d07af54960ce0e7adb2e0fe-72da1f32e38e3557947b00003d96bafd # ln -f ./dd/d9/ddd97aa6f624d4f54968d2c4956fc3a9d796b31b-6bf7c122fefb3157ad3500003d96bafd ./dd/d9/ddd97aa6f624d4f54968d2c4956fc3a9d796b31b-90fd1415e7e53157112800003d96bafd -------------------------------------------------------------- Unexpected objects found: 0 Attachments processed: 43500 Different attachments with similar hashes skipped: 0 Attachments deduplicated: 3 File system blocks freed up: 1800 Attachment deduplication attempts failed: 0 Hash files created: 1 Hash files creation attempts failed: 0 Hash files re-linked: 0 Hash files re-link attempts failed: 0 Orphaned hash files: 0 Invalid hash files (not a regular file): 0 -------------------------------------------------------------- # cd /vmail/attachments # ls -li ./30/b3/ ./30/b3/hashes/ ./30/b3/: total 1996 7464083 -rw------- 1 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545-7ad0a411d17c31572b7a01003d96bafd 7464082 -rw------- 6 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545-bb6eae04a67c3157287f01003d96bafd 7464082 -rw------- 6 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545-bd6eae04a67c3157287f01003d96bafd 7464082 -rw------- 6 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545-bf6eae04a67c3157287f01003d96bafd 7464082 -rw------- 6 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545-c36eae04a67c3157287f01003d96bafd 7464082 -rw------- 6 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545-c56eae04a67c3157287f01003d96bafd 7464084 drwx------ 2 vmail vmail 512 May 10 09:16 hashes ./30/b3/hashes/: total 332 7464082 -rw------- 6 vmail vmail 337719 May 10 09:16 30b367c584a123eee59478adf3e4f4c9e1226545 # ls -li ./6f/3f/ ./6f/3f/hashes/ ./6f/3f/: total 644 15088414 -rw------- 1 vmail vmail 326656 May 13 11:23 6f3fa3e4d374a9c80d07af54960ce0e7adb2e0fe-72da1f32e38e3557947b00003d96bafd 15088422 -rw------- 2 vmail vmail 326656 May 13 11:23 6f3fa3e4d374a9c80d07af54960ce0e7adb2e0fe-b1935817ed753557546700003d96bafd 15088448 drwx------ 2 vmail vmail 512 May 13 11:23 hashes ./6f/3f/hashes/: total 320 15088422 -rw------- 2 vmail vmail 326656 May 13 11:23 6f3fa3e4d374a9c80d07af54960ce0e7adb2e0fe # ls -li ./dd/d9/ ./dd/d9/hashes/ ./dd/d9/: total 748 80548 -rw------- 3 vmail vmail 250640 May 10 18:19 ddd97aa6f624d4f54968d2c4956fc3a9d796b31b-68f7c122fefb3157ad3500003d96bafd 80548 -rw------- 3 vmail vmail 250640 May 10 18:19 ddd97aa6f624d4f54968d2c4956fc3a9d796b31b-6bf7c122fefb3157ad3500003d96bafd 80547 -rw------- 1 vmail vmail 250640 May 10 18:19 ddd97aa6f624d4f54968d2c4956fc3a9d796b31b-90fd1415e7e53157112800003d96bafd 80549 drwx------ 2 vmail vmail 512 May 10 18:19 hashes ./dd/d9/hashes/: total 248 80548 -rw------- 3 vmail vmail 250640 May 10 18:19 ddd97aa6f624d4f54968d2c4956fc3a9d796b31b # doveconf -n # 2.2.24 (a82c823): /usr/local/etc/dovecot/dovecot.conf # Pigeonhole version 0.4.14 (099a97c) # OS: FreeBSD 10.3-RELEASE i386 auth_default_realm = example.com auth_mechanisms = digest-md5 cram-md5 plain apop doveadm_password = # hidden, use -P to show it first_valid_gid = 1000 first_valid_uid = 1000 lda_mailbox_autosubscribe = yes listen = * mail_attachment_dir = /vmail/attachments mail_gid = vmail mail_home = /vmail/%d/%n mail_location = mdbox:~/mdbox mail_plugins = quota zlib acl mail_shared_explicit_inbox = yes mail_uid = vmail 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 namespace { list = children location = mdbox:%%h/mdbox:INDEXPVT=~/mdbox/shared/%%u prefix = shared/%%u/ separator = / subscriptions = no type = shared } namespace inbox { inbox = yes location = mailbox Archives { special_use = \Archive } mailbox Drafts { special_use = \Drafts } mailbox Junk { auto = subscribe special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = separator = / } passdb { args = scheme=plain username_format=%n /usr/local/etc/dovecot/dovecot.auth/%d.passwd driver = passwd-file } plugin { acl = vfile acl_shared_dict = file:/vmail/shared-mailboxes.db antispam_backend = mailtrain antispam_mail_notspam = report_ham antispam_mail_sendmail = /usr/local/libexec/dovecot/dovecot-lda antispam_mail_sendmail_args = -d;spam(a)example.com;-m antispam_mail_spam = report_spam antispam_spam = Junk antispam_trash = Trash;train_ham;train_prob;train_spam quota = dict:User quota::file:%h/dovecot-quota quota_rule = *:storage=2G quota_rule2 = Trash:storage=+10%% quota_rule3 = Spam:storage=+20%% quota_status_nouser = DUNNO quota_status_success = DUNNO sieve_after = /usr/local/etc/dovecot/sieve/sieve.after sieve_before = /usr/local/etc/dovecot/sieve/sieve.before sieve_vacation_min_period = 0 zlib_save = gz zlib_save_level = 3 } postmaster_address = postmaster(a)example.com protocols = imap lmtp sieve pop3 quota_full_tempfail = yes service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } unix_listener auth-userdb { user = vmail } } service config { unix_listener config { mode = 0600 user = vmail } } service imap-login { inet_listener imaps { port = 0 } process_limit = 200 } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0660 user = postfix } user = vmail } service pop3-login { inet_listener pop3s { port = 0 } } service quota-status { client_limit = 1 executable = quota-status -p postfix unix_listener /var/spool/postfix/private/quota-status { user = postfix } } ssl_cert = </etc/ssl/certs/mx.example.com.crt ssl_key = </etc/ssl/private/mx.example.com.key userdb { args = username_format=%n /usr/local/etc/dovecot/dovecot.auth/%d.passwd driver = passwd-file } verbose_proctitle = yes protocol imap { mail_plugins = quota zlib acl antispam imap_quota imap_zlib imap_acl } protocol lmtp { mail_plugins = quota zlib acl sieve }

1 1

offtopic: Solr compatible IMAP client
by Andy Smith 04 Jun '18

04 Jun '18

Hi, not sure if I'm allowed to go this off topic on here, sorry if not! I've just installed Solr FTS for Dovecot and its great, as is Dovecot! ;) It works perfectly for fast searches using Roundcube, but can anyone suggest any Windows and/or Linux mail clients that work well with IMAP searches rather than doing their own searches on local copies of mails? I've had a look at Thunderbird and you can use IMAP search, buy you have to manually select it from an advanced search dialogue and it seems you cannot make this the default behaviour. I also tried OperaMail but it doesn't appear to work at all (only header is searchable without downloading local copies). I'm pretty sure Outlook will only use its own search engine on its local copy of data. thanks a lot, Andy. PS this guide was really helpful for setting up Solr FTS with a recent release of Solr (I'm using 6.5), might be worth including a link somewhere on the Dovecot wiki?: http://mor-pah.net/2016/08/15/dovecot-2-2-with-solr-6-or-5

4 7

replication and .dovecot.lda-dupes
by Patrick Cernko 25 Apr '18

25 Apr '18

Hi list, this question was already posted a few years ago (https://www.dovecot.org/list/dovecot/2014-November/098585.html) I already asked the original queriest and he told me, that he never got an solution or workaround but it was not important enough for him. When using replication in conjunction with sieve vacations, the .dovecot.lda-dupes file is not synced with the other server. So when delivering to both servers (round-robin or randomized), senders might get more vacation mails than configured as the other server does not know, that the first one already sent a vacation message. Is this a bug or intentional? If it is a bug, I hereby ask for a fix, please. We are using Dovecot version 2.2.27 on Debian/stretch. This is dovecot -n (hostnames anonymized): # 2.2.27 (c0f36b0): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.16 (fed8554) # OS: Linux 4.9.76.1.amd64-smp x86_64 Debian 9.3 auth_verbose = yes default_vsz_limit = 2 G doveadm_password = # hidden, use -P to show it doveadm_port = 12345 listen = * login_log_format_elements = pid=%p user=<%u> method=%m rip=%r lip=%l mpid=%e %c mail_attachment_dir = /IMAP/mail/attachments mail_attachment_fs = sis-queue /IMAP/mail/attachments/queue:posix mail_home = /IMAP/mail/mailboxes/%u mail_location = mdbox:~/mdbox mail_log_prefix = "%s(%u[%p]): " mail_max_userip_connections = 0 mail_plugins = " notify replication zlib fts fts_squat" maildir_stat_dirs = yes 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 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/ldap.conf driver = ldap } plugin { fts = squat fts_autoindex = yes fts_squat = partial=4 full=10 mail_replica = tcp:other-server sieve = file:~/sieve;active=~/.dovecot.sieve zlib_save = gz zlib_save_level = 3 } postmaster_address = <> protocols = " imap lmtp sieve" service aggregator { fifo_listener replication-notify-fifo { mode = 0666 } unix_listener replication-notify { mode = 0666 } } service anvil { client_limit = 2250 } service auth { client_limit = 2447 } service doveadm { inet_listener doveadm-server { port = 12345 } } service imap-login { inet_listener imap { port = 0 } process_limit = 2047 } service imap { process_limit = 2047 } service lmtp { inet_listener lmtp { port = 24 } } service pop3-login { inet_listener pop3 { port = 0 } inet_listener pop3s { port = 0 } } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { mode = 0666 } } ssl_cert = </etc/ssl/certificate.pem ssl_key = # hidden, use -P to show it userdb { args = /etc/dovecot/userdb.overrides driver = passwd-file } userdb { args = /etc/dovecot/ldap.conf driver = ldap } verbose_proctitle = yes protocol lmtp { auth_username_format = %n mail_plugins = " notify replication zlib fts fts_squat sieve" } protocol lda { mail_plugins = " notify replication zlib fts fts_squat sieve" } And this is /etc/dovecot/ldap.conf (hostnames anonymized): uris = ldaps://ldap1/ ldaps://ldap2/ base = dc=domain user_filter = (&(objectClass=posixAccount)(uid=%u)) user_attrs = \ =user=%{ldap:uid}, \ =uid=%{ldap:uidNumber}, \ =gid=%{ldap:gidNumber} pass_filter = (&(objectClass=posixAccount)(uid=%u)) iterate_filter = (&(objectClass=posixAccount)(istMailHomeServer=servername)) auth_bind = yes /etc/dovecot/userdb.override is currently an empty file. P.S.: Although I do not think, that this has something to do with our problem, I should mention that we run SIS with system uids. This needs some permission and posixacl tweaks on /IMAP/mail/attachments to work: # force all files created in this dir recursively) to have mode 0666 setfacl -d -m group::rwx -m o:rwx /IMAP/mail/attachments (you have to enable posixacls for the corresponding filesystem!) # trick dovecot to inherit parent dir's permissions (recursively) chmod 2777 /IMAP/mail/attachments Feel free to add these tweaks to the SIS documentation. ;-) Best Regards, -- Patrick Cernko <pcernko(a)mpi-klsb.mpg.de> +49 681 9325 5815 Joint Administration: Information Services and Technology Max-Planck-Institute fuer Informatik & Softwaresysteme

2 2

Strange "IMAP connection broken (server response)" errors
by Jozsef Kadlecsik 20 Mar '18

20 Mar '18

Hello, We upgraded one of our dovecot servers to debian stretch with dovecot 2.2.27 and since then one of our users has been experiencing random IMAP failures. We enabled raw logging at the server side and it shows normal IMAP commands/responses: 1507292522.222427 * 6 FETCH (FLAGS () BODYSTRUCTURE ("text" "plain" ("charset" "us-ascii") NIL NIL "7bit" 4645 112 NIL NIL NIL NIL)) 1507292522.222653 00000011 OK Fetch completed (0.006 + 0.000 secs). On the client side the user runs alpine and the corresponding debug lines: IMAP DEBUG 14:22:02.216167: 00000011 FETCH 6 (BODYSTRUCTURE FLAGS) 14:22:02.217396 IMAP 14:22:02 10/6 mm_notify bye: {[127.0.0.1]:1555/imap/user="ha4aa"}INBOX: [CLOSED] IMAP connection broken (server response) 14:22:02.217471 IMAP 14:22:02 10/6 mm_log error: [CLOSED] IMAP connection broken (server response) The "[127.0.0.1]:1555/imap/user="ha4aa" part in the log comes from an socat inserted between the client and the server to check independetly the imap session. According to socat, the server response didn't reach the client!: 00000010 OK Fetch completed (0.005 + 0.000 secs).\r > 2017/10/06 14:22:02.216299 length=40 from=845 to=884 00000011 FETCH 6 (BODYSTRUCTURE FLAGS)\r and here ends the socat log, the server response didn't reach the client. The same alpine package is used against older dovecot servers from debian jessie and works flawlessly. The server and client are both KVM guests and there's no any content filtering software between them. There's no corresponding error in the dovecot log file and dovecot didn't regard the connection broken and detected client close: ... Oct 6 14:19:44 mail2 dovecot: imap(ha4aa): Debug: Mailbox INBOX: Opened mail UID=55244 because: MIME part Oct 6 14:22:02 mail2 dovecot: imap(ha4aa): Connection closed in=797 out=73151 We are out of the ideas what can be the reason for the random lost server responses. Any help is appreciated! Best regards, Jozsef -- E-mail : kadlecsik.jozsef(a)wigner.mta.hu PGP key: http://www.kfki.hu/~kadlec/pgp_public_key.txt Address: Wigner Research Centre for Physics, Hungarian Academy of Sciences H-1525 Budapest 114, POB. 49, Hungary

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