- dovecot - dovecot.org

doveadm: Error: open(/proc/self/io) failed
by me＠tdiehl.org 06 Aug '19

06 Aug '19

Hi, I am running dovecot-2.2.36-3.el7.x86_64 on a Centos 7 machine. I keep seeing the following errors in the dovecot.log: Jul 22 12:52:04 vmail2 dovecot: doveadm: Error: open(/proc/self/io) failed: Permission denied Dovecot -n is listed below: # 2.2.36 (1f10bfa63): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.24 (124e06aa) # OS: Linux 3.10.0-957.21.3.el7.x86_64 x86_64 CentOS Linux release 7.6.1810 (Core) # Hostname: vmail2.kmg.mydomain.com auth_master_user_separator = * auth_mechanisms = PLAIN LOGIN deliver_log_format = from=%{from}, envelope_sender=%{from_envelope}, subject=%{subject}, msgid=%m, size=%{size}, %$ dict { acl = mysql:/etc/dovecot/dovecot-share-folder.conf quotadict = mysql:/etc/dovecot/dovecot-used-quota.conf } doveadm_password = # hidden, use -P to show it doveadm_port = 2525 first_valid_uid = 2000 last_valid_uid = 2000 mail_gid = 2000 mail_location = maildir:%Lh/Maildir/:INDEX=%Lh/Maildir/ mail_plugins = quota mailbox_alias acl mail_log notify stats replication mail_uid = 2000 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 imapsieve vnd.dovecot.imapsieve namespace { inbox = yes location = mailbox Archive { auto = no special_use = \Archive } mailbox Archives { auto = no special_use = \Archive } mailbox "Deleted Messages" { auto = no special_use = \Trash } mailbox Drafts { auto = subscribe special_use = \Drafts } mailbox Junk { auto = subscribe special_use = \Junk } mailbox "Junk E-mail" { auto = no special_use = \Junk } mailbox Sent { auto = subscribe special_use = \Sent } mailbox "Sent Items" { auto = no special_use = \Sent } mailbox "Sent Messages" { auto = no special_use = \Sent } mailbox Spam { auto = no special_use = \Junk } mailbox Trash { auto = subscribe special_use = \Trash } prefix = separator = / type = private } namespace { list = children location = maildir:%%Lh/Maildir/:INDEX=%%Lh/Maildir/Shared/%%Ld/%%Ln prefix = Shared/%%u/ separator = / subscriptions = yes type = shared } passdb { args = /etc/dovecot/dovecot-mysql.conf driver = sql } passdb { args = /etc/dovecot/dovecot-master-users driver = passwd-file master = yes } plugin { acl = vfile acl_shared_dict = proxy::acl fts_autoindex = yes fts_autoindex_max_recent_msgs = 50 imapsieve_mailbox1_before = file:/usr/lib64/dovecot/sieve/report-spam.sieve imapsieve_mailbox1_causes = COPY imapsieve_mailbox1_name = Spam imapsieve_mailbox2_before = file:/usr/lib64/dovecot/sieve/report-ham.sieve imapsieve_mailbox2_causes = COPY imapsieve_mailbox2_from = Spam imapsieve_mailbox2_name = * mail_log_events = delete undelete expunge mailbox_delete mailbox_rename mail_log_fields = uid box msgid size from subject mail_replica = tcp:vmail1.kmg.mydomain.com mailbox_alias_new = Sent Messages mailbox_alias_new2 = Sent Items mailbox_alias_old = Sent mailbox_alias_old2 = Sent quota = dict:user::proxy::quotadict quota_grace = 10%% quota_warning = storage=100%% quota-warning 100 %u quota_warning2 = storage=95%% quota-warning 95 %u quota_warning3 = storage=90%% quota-warning 90 %u quota_warning4 = storage=85%% quota-warning 85 %u sieve = ~/sieve/dovecot.sieve sieve_before = /var/vmail/sieve/dovecot.sieve sieve_dir = ~/sieve sieve_global_dir = /var/vmail/sieve sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.execute sieve_max_redirects = 30 sieve_pipe_bin_dir = /usr/lib64/dovecot/sieve sieve_plugins = sieve_imapsieve sieve_extprograms sieve_vacation_send_from_recipient = yes stats_refresh = 30 secs stats_track_cmds = yes } protocols = pop3 imap sieve lmtp service aggregator { fifo_listener replication-notify-fifo { user = vmail } unix_listener replication-notify { user = vmail } } service auth { unix_listener /var/spool/postfix/private/dovecot-auth { group = postfix mode = 0666 user = postfix } unix_listener auth-master { group = vmail mode = 0666 user = vmail } unix_listener auth-userdb { group = vmail mode = 0660 user = vmail } } service config { unix_listener config { user = vmail } } service dict { unix_listener dict { group = vmail mode = 0660 user = vmail } } service doveadm { inet_listener { port = 2525 } user = vmail } service imap-login { process_limit = 500 service_count = 1 } service lmtp { executable = lmtp -L inet_listener lmtp { address = 127.0.0.1 port = 24 } process_min_avail = 5 unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0600 user = postfix } user = vmail } service managesieve-login { inet_listener sieve { address = 127.0.0.1 port = 4190 } } service pop3-login { service_count = 1 } service quota-warning { executable = script /usr/local/bin/dovecot-quota-warning.sh unix_listener quota-warning { group = vmail mode = 0660 user = vmail } } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { group = vmail mode = 0666 } } service stats { fifo_listener stats-mail { mode = 0644 user = vmail } inet_listener { address = 127.0.0.1 port = 24242 } } ssl = required ssl_cert = </etc/pki/tls/certs/my_cert.crt ssl_cipher_list = ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:!aNULL:!MD5 ssl_client_ca_file = /etc/pki/tls/cert.pem ssl_key = # hidden, use -P to show it ssl_prefer_server_ciphers = yes syslog_facility = local5 userdb { args = /etc/dovecot/dovecot-mysql.conf driver = sql } protocol lda { lda_mailbox_autocreate = yes lda_mailbox_autosubscribe = yes mail_plugins = quota mailbox_alias acl mail_log notify stats replication sieve } protocol lmtp { lmtp_save_to_detail_mailbox = yes mail_plugins = quota sieve recipient_delimiter = + } protocol imap { imap_client_workarounds = tb-extra-mailbox-sep mail_max_userip_connections = 30 mail_plugins = quota mailbox_alias acl mail_log notify stats replication imap_quota imap_acl imap_stats imap_sieve } protocol pop3 { mail_max_userip_connections = 30 mail_plugins = quota mailbox_alias acl mail_log notify stats replication pop3_client_workarounds = outlook-no-nuls oe-ns-eoh pop3_uidl_format = %08Xu%08Xv } Everything seems to be working properly and the dovecot wiki says that /proc/self/io is for statistics. I am thinking they are harmless but they are generating a bunch of noise in the logs and if harmless, I would like to silence them. Can someone let me know what causes this and if I should be concerned about this? My Google foo has not been helpful on this. Regards, -- Tom me(a)tdiehl.org

7 12

GSSAPI vs group check
by Németh Ákos Ferenc 05 Aug '19

05 Aug '19

Dear All, Is it possible to make any authorization (eg. checking of group membership) in case of GSSAPI authentication? Our dovecot authenticates the users against PAM and GSSAPI. In the PAM file I'm able to check if a user is a member of a selected (e.g mailreader) group. If the user is member, he can login otherwise not (see below). If the user has a valid Kerberos ticket and he tries to login via GSSAPI, I can't restrict him if he is not a member of the selected group. How can I overcome this issue? My config: passdb { driver = pam # [session=yes] [setcred=yes] [failure_show_msg=yes] [max_requests=<n>] # [cache_key=<key>] [<service name>] #args = dovecot } userdb { # <doc/wiki/AuthDatabase.Passwd.txt> driver = passwd # [blocking=no] #args = # Override fields from passwd #override_fields = home=/home/virtual/%u } ...in PAM file: auth [success=1 default=ignore] pam_succeed_if.so user ingroup mailreader auth [success=ignore default=2] pam_succeed_if.so user ingroup admins auth [success=ignore default=1] pam_succeed_if.so uid >= 1000 auth [success=3 default=ignore] pam_winbind.so krb5_auth krb5_ccache_type=FILE cached_login auth [success=ignore default=1] pam_succeed_if.so uid < 1000 auth [success=1 default=ignore] pam_unix.so nullok_secure try_first_pass auth requisite pam_deny.so auth required pam_permit.so Thank you. Br, Ákos

2 3

doveadm sis deduplicate problem
by Peter Benko 03 Aug '19

03 Aug '19

Hi all, I'm running dovecot 2.3.7.1, with mdbox and single instance storage. I use offline deduplication like this: mail_attachment_fs = sis-queue /mailboxes/%d/_attachments_/queue:posix Each week I run doveadm sis deduplicate to deduplicate the mail attachments. Everything was fine until I mistakenly run doveadm sis deduplicate twice, simultaneously. I ended up having some error messages like this: Error: unlink(/mailboxes/domain.com/_attachments_/queue/067518ec61f872420813727326… failed: No such file or directory (in doveadm-sis.c:260) Also, the sis store has a suspicious temporary (leftover?) file (in the according _attachments_/06/75/ dir): -rw------- 4 vmail vmail 941197 Aug 2 15:48 temp.server-name.9633.77f5a7183d74f72b So the question is, shall I be nervous about this temp file? Does the error mean that the deduplication did not finish correctly? Is my mail store in a consistent state now? What shall I do with the temp file? I'd really appreciate some help... Regards, Peter

1 0

Sieve redirect
by B Fischer 03 Aug '19

03 Aug '19

What is the intended way to configure Sieve for the redirect command? Can I do it using in Dovecot (e.g. using the submission config) or does it have to be done in sendmail? I'm running Dovecot in a container and the MTA/MSA is in another container. Dovecot version: 2.3.2.1 (0719df592) - Björn

1 0

index failed
by ＠lbutlr 02 Aug '19

02 Aug '19

When reindexing I go the following error Mailbox test: UID=1: read(/path/to/mail,S=4248,W=4349) failed: Cached message size larger than expected (4248 > 1182, box=test, UID=1) (read reason=mail stream) In this case, the message was an unimportant test message with no content, so I simply removed it, but had it been important what would I need to do? -- Nine-tenths of the universe is the knowledge of the position and direction of everything in the other tenth. Every atom has its biography, every star its file, every chemical exchange its equivalent of the inspector with a clipboard. It is unaccounted for because it is doing the accounting for the rest of it. Nine-tenths of the universe, in fact, is the paperwork. --The Thief of Time

1 0

Question about replication
by Coy Hile 02 Aug '19

02 Aug '19

Good morning, I’m looking at dovecot replication for the first time for a particular use case: The VM running dovecot is currently in a public cloud, and I want to move it on-premises, so I want to replicate all mail data from the older instance to the new (then cutover internal DNS) (and in the process update to newer features on the internal instance such as mdbox vs Maildir). However, the new instance I’m building is internal, would have access to the internet only via NAT, so the replication would have to be one way. Is there anything in particular that I need to keep in mind when I’m trying to setup this sort of setup? The documentation that I’ve read seems to imply (or assume) synchronous, bidirectional replication. Thanks, and apologies if this is an obvious question; this is my first foray into doing something not utterly trivial with Dovecot.

2 3

Re: Panic: Module context expire_mail_user_module missing (Debian 10)
by Alexander Dalloz 02 Aug '19

02 Aug '19

Am 2019-08-02 11:05, schrieb Thomas Krause: Thomas, please keep the discussion on list. There is zero need to copy send any list discussion to my personal address. > # diff dovecot.conf dovecot.conf-ok > 5c5 > < mail_plugins = quota mailbox_alias acl zlib expire > --- >> mail_plugins = quota mailbox_alias acl zlib #expire > 170c170 > < expire = mysql:/etc/dovecot/dovecot-expire.conf > --- >> #expire = mysql:/etc/dovecot/dovecot-expire.conf > > > # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf > # Pigeonhole version 0.5.4 () > doveconf: Warning: NOTE: You can get a new clean config file with: > doveconf -Pn > dovecot-new.conf > doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:16: > ssl_dh_parameters_length is no longer needed > doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:17: > ssl_protocols has been replaced by ssl_min_protocol > doveconf: Warning: NOTE: You can get a new clean config file with: > doveconf -Pn > dovecot-new.conf > doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:16: > ssl_dh_parameters_length is no longer needed > doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:17: > ssl_protocols has been replaced by ssl_min_protocol Fix those obvious things. > # OS: Linux 4.19.0-5-amd64 x86_64 Debian 10.0 > # Hostname: mail.example.org > auth_mechanisms = PLAIN LOGIN > dict { > acl = mysql:/etc/dovecot/dovecot-share-folder.conf > expire = mysql:/etc/dovecot/dovecot-expire.conf > quotadict = mysql:/etc/dovecot/dovecot-used-quota.conf > } > first_valid_uid = 1001 > last_valid_uid = 1001 > login_log_format_elements = user=<%u> rip=%r mpid=%e > session=<%{session}> > mail_gid = 1001 > mail_plugins = quota mailbox_alias acl zlib expire The expire plugin enabled under mail_plugins, but no configuration in the plugins { } section. So it has zeor function as you have not defined the mailboxes to track. > mail_uid = 1001 > 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 = yes > location = > mailbox Archive { > auto = no > special_use = \Archive > } > mailbox Archives { > auto = no > special_use = \Archive > } > mailbox "Deleted Messages" { > auto = no > special_use = \Trash > } > mailbox Drafts { > auto = subscribe > special_use = \Drafts > } > mailbox Junk { > auto = subscribe > special_use = \Junk > } > mailbox "Junk E-mail" { > auto = no > special_use = \Junk > } > mailbox Sent { > auto = subscribe > special_use = \Sent > } > mailbox "Sent Items" { > auto = no > special_use = \Sent > } > mailbox "Sent Messages" { > auto = no > special_use = \Sent > } > mailbox Spam { > auto = no > special_use = \Junk > } > mailbox Trash { > auto = subscribe > special_use = \Trash > } > prefix = > separator = / > type = private > } > passdb { > args = /etc/dovecot/dovecot-mysql.conf > driver = sql > } > plugin { > acl = vfile > acl_shared_dict = proxy::acl > auth_socket_path = /var/run/dovecot/auth-master > mailbox_alias_new = Sent Messages > mailbox_alias_new2 = Sent Items > mailbox_alias_old = Sent > mailbox_alias_old2 = Sent > quota = dict:user::proxy::quotadict > quota_grace = 10%% > quota_rule = *:storage=1G > quota_warning = storage=100%% quota-warning 100 %u > quota_warning2 = storage=95%% quota-warning 95 %u > quota_warning3 = storage=90%% quota-warning 90 %u > quota_warning4 = storage=85%% quota-warning 85 %u > sieve = ~/.dovecot.sieve > sieve_dir = ~/sieve > sieve_max_redirects = 30 > zlib_save = gz > zlib_save_level = 6 > } Above not expire configuration. See https://wiki.dovecot.org/Plugins/Expire And you should consider migrating to the autoexpunge settings. > protocols = pop3 imap sieve lmtp > service anvil { > client_limit = 1203 > } > service auth { > client_limit = 1400 > unix_listener /var/spool/postfix/private/dovecot-auth { > group = postfix > mode = 0666 > user = postfix > } > unix_listener auth-client { > group = www-data > mode = 0660 > } > unix_listener auth-master { > group = vmail > mode = 0666 > user = vmail > } > unix_listener auth-userdb { > group = vmail > mode = 0660 > user = vmail > } > } > service dict { > process_limit = 150 > unix_listener dict { > group = vmail > mode = 0660 > user = vmail > } > } > service imap-login { > process_limit = 500 > service_count = 1 > } > service lmtp { > unix_listener /var/spool/postfix/private/dovecot-lmtp { > group = postfix > mode = 0660 > user = postfix > } > user = vmail > } > service pop3-login { > process_limit = 500 > service_count = 1 > } > service quota-warning { > executable = script /usr/local/bin/dovecot-quota-warning.sh > unix_listener quota-warning { > group = vmail > mode = 0660 > user = vmail > } > } > ssl = required > ssl_cert = </etc/ssl/ssl.crt/mail.example.org.pem > ssl_cipher_list = > EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA256:EECDH:+CAMELLIA128:+AES128:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:!IDEA:!ECDSA:kEDH:CAMELLIA128-SHA:AES128-SHA > ssl_key = # hidden, use -P to show it > ssl_prefer_server_ciphers = yes > userdb { > args = /etc/dovecot/dovecot-mysql.conf > driver = sql > } > protocol lda { > auth_socket_path = /var/run/dovecot/auth-master > lda_mailbox_autocreate = yes > lda_mailbox_autosubscribe = yes > mail_plugins = quota mailbox_alias acl zlib expire sieve > postmaster_address = root > } > protocol lmtp { > lmtp_save_to_detail_mailbox = yes > mail_plugins = quota mailbox_alias acl zlib expire sieve > postmaster_address = postmaster > recipient_delimiter = + > } > protocol imap { > imap_client_workarounds = tb-extra-mailbox-sep > mail_max_userip_connections = 30 > mail_plugins = quota mailbox_alias acl zlib expire imap_quota > imap_acl > } > protocol pop3 { > mail_max_userip_connections = 30 > mail_plugins = quota mailbox_alias acl zlib expire > pop3_client_workarounds = outlook-no-nuls oe-ns-eoh > } Alexander

1 0

Panic: Module context expire_mail_user_module missing (Debian 10)
by Thomas Krause 02 Aug '19

02 Aug '19

Hi all, I tried to migrate a mailserver from Debian 9 (Dovecot 2.2.27) to Debian 10 (Dovecot 2.3.4.1). I moved the mail-partition and /etc/dovecot from the old to the new server. Dovecot started with 2 warnings. When trying to fetch mails via pop3 the server crashes: Aug 1 16:56:47 mail19 dovecot: pop3-login: Login: user=<testuser>, rip=::1, mpid=22394, session=<rutwcw+PRp4AAAAAAAAAAAAAAAAAAAAB> Aug 1 16:56:47 mail19 dovecot: pop3(testuser)<22394><rutwcw+PRp4AAAAAAAAAAAAAAAAAAAAB>: Panic: Module context expire_mail_user_module missing Aug 1 16:56:47 mail19 dovecot: pop3(testuser)<22394><rutwcw+PRp4AAAAAAAAAAAAAAAAAAAAB>: Error: Raw backtrace: /usr/lib/dovecot/libdovecot.so.0(+0xdb13b) [0x7fd14ea7713b] -> /usr/lib/dovecot/libdovecot.so.0 (+0xdb1d1) [0x7fd14ea771d1] -> /usr/lib/dovecot/libdovecot.so.0(+0x4a001) [0x7fd14e9e6001] -> /usr/lib/dovecot/modules/lib20_expire_plugin.so(+0x23b2) [0x7fd14e7953b2] -> /usr/lib/dovecot/libdovecot-storage.so.0 (hook_mailbox_allocated+0x89) [0x7fd14eb89409] -> /usr/lib/dovecot/libdovecot-storage.so.0(mailbox_alloc+0xda) [0x7fd14eb84c5a] -> dovecot/pop3(client_init_mailbox+0x58) [0x55781fb5fba8] -> dovecot/pop3(+0x5645) [0x55781fb5e645] -> dovecot/pop3(+0x5882) [0x55781fb5e882] -> /usr/lib/dovecot/libdovecot.so.0(+0x6f601) [0x7fd14ea0b601] -> /usr/lib/dovecot/libdovecot.so.0(+0x6f97b) [0x7fd14ea0b97b] -> /usr/lib/dovecot/libdo vecot.so.0(+0x7030d) [0x7fd14ea0c30d] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x6f) [0x7fd14ea8d5ef] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x136) [0x7fd14ea8ebe6] -> /usr/l ib/dovecot/libdovecot.so.0(io_loop_handler_run+0x4c) [0x7fd14ea8d68c] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_run+0x40) [0x7fd14ea8d7f0] -> /usr/lib/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7fd14e a0dfd3] -> dovecot/pop3(main+0x2cf) [0x55781fb5e13f] -> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb) [0x7fd14e7f909b] -> dovecot/pop3(_start+0x2a) [0x55781fb5e29a] Aug 1 16:56:47 mail19 dovecot: pop3(testuser)<22394><rutwcw+PRp4AAAAAAAAAAAAAAAAAAAAB>: Fatal: master: service(pop3): child 22394 killed with signal 6 (core dumps disabled - https://dovecot.org/bugreport.h tml#coredumps) What can I do? I tried to enable core dumps (installed systemd-coredump and modified limits.conf) but it didn't work. Best regards, Thomas.

2 3

Patch needed for debian buster in version 2.2.36.1
by Simone Lazzaris 02 Aug '19

02 Aug '19

Hi all; I've just compiled version 2.2.36.1 on a new debian buster (debian 10) and it seems that this patch https://github.com/dovecot/core/commit/ 63a74b9e8e0604486a15a879e7f1a27257322400.patch is needed to make it work. Without the patch, the authentication segfaults. *Simone Lazzaris* *Qcom S.p.A.* simone.lazzaris(a)qcom.it[1] | www.qcom.it[2] * LinkedIn[3]* | *Facebook*[4] [5] -------- [1] mailto:simone.lazzaris@qcom.it [2] https://www.qcom.it [3] https://www.linkedin.com/company/qcom-spa [4] http://www.facebook.com/qcomspa [5] https://www.qcom.it/includes/NUOVAemail-banner.gif

2 1

IMAP frontend authenticating proxy with GSSAPI/Kerberos SSO
by Gert van Dijk 01 Aug '19

01 Aug '19

Hi, My IMAP backend server is lacking SSO authentication, so I am trying to set up Dovecot in front of it as an authenticating proxy. Fortunately, my backend server provides a way to ignore the password provided and will simply trust the username given to be authenticated, using plain login authentication. I'm struggling with setting this up, as it seems to me that as soon as I enable GSSAPI/Kerberos SSO in Dovecot it ignores my passdb proxy settings and it creates a local mail store instead. Is this behavior intentional, and why? See also my Q on Serverfault.com [1], where some user has reported this set up to be working with the same backend server and provided some hints, but I believe I'm hitting a combination that cannot be working with this version. Dovecot version: v2.3.4.1 (from Debian Buster) dovecot -n (I'm using only a single flat file dovecot.conf): ===== # dovecot -n # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.4 () # OS: Linux 4.15.0-46-generic x86_64 Debian 10.0 overlay # Hostname: imap.sub.mydomain.tld auth_debug = yes auth_default_realm = MY-REALM.DOMAIN.TLD auth_gssapi_hostname = imap.sub.mydomain.tld auth_krb5_keytab = /etc/dovecot/imap.keytab auth_mechanisms = gssapi auth_realms = MY-REALM.DOMAIN.TLD auth_username_format = %n auth_verbose = yes log_path = /dev/stderr mail_gid = 65534 mail_location = mbox:/tmp mail_uid = 65534 passdb { args = proxy=y host=127.0.0.1 port=1143 pass=#hidden_use-P_to_show# driver = static } protocols = imap ssl = required ssl_cert = </etc/dovecot-ssl/cert.crt ssl_cipher_list = ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384 ssl_key = # hidden, use -P to show it ssl_min_protocol = TLSv1.2 ssl_prefer_server_ciphers = yes ===== My comments are lost with "dovecot -n", so here I repeat some why's. ===== # uid/gid of nobody or else: # imap(username)<15><6SCG0QOPgtcKAAYE>: Error: Couldn't drop privileges: User is missing UID (see mail_uid setting) mail_uid = 65534 mail_gid = 65534 # Have to set dummy mail_location or else: # Error: mail_location not set and autodetection failed: Mail storage autodetection failed with home=(not set) mail_location = mbox:/tmp ===== (Ideally, I don't want to set any local storage storage, Dovecot should just be a proxy in my case.) Log, debug enabled, with client connecting: ===== master: Info: Dovecot v2.3.4.1 (f79e8e7e4) starting up for imap auth: Debug: Loading modules from directory: /usr/lib/dovecot/modules/auth auth: Debug: Module loaded: /usr/lib/dovecot/modules/auth/lib20_auth_var_expand_crypt.so auth: Debug: Loading modules from directory: /usr/lib/dovecot/modules/auth auth: Debug: Module loaded: /usr/lib/dovecot/modules/auth/libmech_gssapi.so auth: Debug: Read auth token secret from /var/run/dovecot/auth-token-secret.dat auth: Debug: auth client connected (pid=9) auth: Debug: client in: AUTH 1 GSSAPI service=imap secured=tls session=9WOjSwWP8toKAAYE lip=9.9.9.9 rip=1.2.3.4 lport=143 rport=56050 local_name=sub.mydomain.tld ssl_cipher=ECDHE-RSA-AES128-GCM-SHA256 ssl_cipher_bits=128 ssl_pfs=KxECDHE ssl_protocol=TLSv1.2 auth: Debug: gssapi(?,1.2.3.4,<9WOjSwWP8toKAAYE>): Obtaining credentials for imap(a)sub.mydomain.tld auth: Debug: client passdb out: CONT 1 auth: Debug: client in: CONT<hidden> auth: Debug: gssapi(username,1.2.3.4,<9WOjSwWP8toKAAYE>): security context state completed. auth: Debug: client passdb out: CONT 1 YIGZBgkqhki[...]7Bm1G auth: Debug: client in: CONT<hidden> auth: Debug: gssapi(username,1.2.3.4,<9WOjSwWP8toKAAYE>): Negotiated security layer auth: Debug: client passdb out: CONT 1 BQQF/w[...]yjNOo= auth: Debug: client in: CONT<hidden> auth: Debug: static(username,1.2.3.4,<9WOjSwWP8toKAAYE>): lookup auth: Info: static(username,1.2.3.4,<9WOjSwWP8toKAAYE>): No password returned (and no nopassword) auth: Debug: client passdb out: OK 1 user=username original_user=username(a)MY-REALM.DOMAIN.TLD auth: Debug: master in: REQUEST 3940810753 9 1 740b6a075ea21dbe10397f3734262bbe session_pid=12 request_auth_token auth: Debug: master userdb out: USER 3940810753 username auth_token=d1503de7036a68a85ea9db25f32bc9df3ebf08a8 auth_user=username(a)MY-REALM.DOMAIN.TLD imap-login: Info: Login: user=<username>, method=GSSAPI, rip=1.2.3.4, lip=9.9.9.9, mpid=12, TLS, session=<9WOjSwWP8toKAAYE> ===== The good news is that everything related to Kerberos/GSSAPI authentication seems to work fine! Noteworthy in the above output I think is the line "auth: Debug: client passdb out: ..." which does not mention any proxy related settings any longer which aligns with my observations: - The client is then logged into an empty mailbox in local storage. Not okay. - No attempt to connect to my backend server is made (checked with tcpdump). Not okay. Somehow I start to believe that as soon as I set auth_mechanisms = gssapi, any args/field in passdb are ignored. Is that a bug or am I looking at a feature? What else have I tried: - Using imapc proxy [2], but that example config does not work in my Dovecot version with the error: auth: Error: prefetch(username,1.2.3.4,): userdb lookup not possible with only userdb prefetch - Using a passdb with master=yes and pass=yes. passdb { driver = static args = proxy=y host=127.0.0.1 port=1143 pass=dummypass master = yes pass = yes } This fails with the error: auth: Fatal: Master passdb can't have pass=yes if there are no passdbs master: Error: service(auth): command startup failed, throttling for 2 secs imap-login: Info: Disconnected: Auth process broken (disconnected before auth was ready, waited 0 secs): user=<>, rip=1.2.3.4, lip=9.9.9.9, session=<0i46qgWPntsKAAYE> imap-login: Warning: Timeout leak: 0x7efe483e8120 (auth-server-connection.c:397) Any help or clues are very much appreciated. Thanks! [1]: https://serverfault.com/q/951010/135437 [2]: https://wiki.dovecot.org/HowTo/ImapcProxy Gert van Dijk

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