October 2025 - dovecot

doveadm sync issue
by Dan Whitehouse 06 Nov '25

06 Nov '25

Hi, I am running Dovecot on Debian trixie (dovecot-core/stable,now 1:2.4.1+dfsg1-6 amd64). Under the previous version, which I believe was 2.3, I was able to run a sync script with the following syntax: doveadm sync -u <user> remote:<user>@<host.tld> This worked very well and I was able to sync my mail. Having upgraded, this syntax produces the following error: dsync-server: invalid option -- ‘U' Error: doveadm: Unexpected or incomplete option: -U Even though my script doesn’t pass “-U” explicitly I believe that it is passed internally: https://github.com/dovecot/core/blob/main/src/doveadm/doveadm-settings.c#L1… core/src/doveadm/doveadm-settings.c at main · dovecot/core github.com Confusingly the online help still displays: doveadm dsync-server —help doveadm dsync-server [-r <rawlog path>] [-T <timeout secs>] [-U] Here we can see that the “-U” option (despite all the above) appears to have been removed from the code: https://github.com/dovecot/core/commit/4c04e4c30fd4817a8b0e11d04d9681173f69… global: Remove replicator · dovecot/core@4c04e4c github.com I have added the following to /etc/dovecot/local.conf: dsync_remote_cmd = "ssh -l%{login} %{host} doveadm dsync-server -u%{user}” (Note that I override the “-U”) and sync once again works properly. Many thanks for your attention, Dan Whitehouse

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Dovecot 2.4.0: Error with Oauth2 login after successful introspection
by sukanyamorbale＠gmail.com 31 Oct '25

31 Oct '25

Hello, I upgraded Dovecot from version 2.3.21 to 2.4.0. In version 2.3.21, I encountered issues with OAuth2 authentication that had worked correctly in earlier releases. Specifically, the active_attribute check was failing, even though Keycloak was sending the active value as true. After upgrading to Dovecot 2.4.0, the active attribute is now validated successfully, and token introspection completes as expected. However, I am now encountering the following error: 2025-10-30 14:43:41.438 Oct 30 13:43:41 auth: Panic: file expansion-statement.c: line 30 (var_expand_execute_stmt): assertion failed: (value != NULL) 2025-10-30 14:43:41.444 Oct 30 13:43:41 auth-worker(354): Debug: conn unix:auth-worker (pid=113,uid=101): Disconnected: Connection closed (fd=-1) 2025-10-30 14:43:41.443 Oct 30 13:43:41 auth: Error: Raw backtrace: #0 test_subprocess_fork[0x7f03870fc510] -> #1 backtrace_append[0x7f03870fc7c0] -> #2 backtrace_get[0x7f03870fc960] -> #3 event_filter_match_iter_init[0x7f0387106bc0] -> #4 i_syslog_fatal_handler[0x7f0387106d00] -> #5 i_panic[0x7f0387033c8e] -> #6 [unw_get_proc_name() failed: -10] -> #7 var_expand_program_execute[0x7f0387070460] -> #8 settings_file_get[0x7f0387083550] -> #9 settings_parse_keyidx_value_nodup[0x7f0387085660] -> #10 settings_parse_keyidx_value_nodup[0x7f0387085d70] -> #11 settings_parse_keyidx_value_nodup[0x7f0387087180] -> #12 settings_get[0x7f03870877b0] -> #13 auth_worker_auth_request_new[0x558c60949050] -> #14 auth_worker_auth_request_new[0x558c609496e0] -> #15 oauth2_json_tree_build[0x7f03870432f0] -> #16 oauth2_json_tree_build[0x7f03870433d0] -> #17 oauth2_request_parse_json[0x7f03870435a0] -> #18 http_client_request_callback[0x7f0387091ee0] -> #19 http_client_connection_lost_peer[0x7f0387094850] -> #20 http_client_peer_connection_failure[0x7f038709a090] -> #21 io_loop_call_io[0x7f0387122780] -> #22 io_loop_handler_run_internal[0x7f0387123aa0] -> #23 io_loop_handler_run[0x7f0387123c40] -> #24 io_loop_run[0x7f0387123e40] -> #25 master_service_run[0x7f0387075720] -> #26 main[0x558c60931e80] -> #27 __libc_init_first[0x7f0386dc9150] -> #28 __libc_start_main[0x7f0386dc9200] -> #29 _start[0x558c609323d0] Here is my current dovecot.conf. dovecot_config_version = 2.4.0 dovecot_storage_version = 2.4.0 protocols = imap pop3 lmtp auth_mechanisms { oauthbearer = yes xoauth2 = yes } oauth2 { introspection_url = https://client-name:client-key@iam.keyclock-url.com/auth/realms/realm-name/… introspection_mode = post active_attribute = active active_value = true username_attribute = preferred_username } userdb static { fields { uid = vmail gid = vmail home = /home/vmail/%{user | domain}/%{user | username} } } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { mode = 0600 user = postfix group = postfix } } service auth { unix_listener /var/spool/postfix/private/auth { mode = 0666 user = postfix group = postfix } unix_listener auth-userdb { mode = 0600 user = vmail } user = dovecot } service auth-worker { user = vmail } log_debug = category=auth auth_verbose = yes auth_debug_passwords = yes mail_driver = maildir mail_home = /home/vmail/%{user | domain}/%{user | username} mail_path = ~ ssl_server_cert_file = /etc/ssl/private/vmail.crt ssl_server_key_file = /etc/ssl/private/vmail.key ssl_server_dh_file = /etc/dovecot/dh.pem mail_debug = yes log_path = /dev/stdout info_log_path = /dev/stdout debug_log_path = /dev/stdout Regards, Sukanya Morbale

1 0

Panic with FTS_BACKEND_FLAG_TOKENIZED_INPUT and virtual mailboxes: file index-search-result.c: line 132
by markus-dovecot＠doits.de 31 Oct '25

31 Oct '25

Originally posted and debugged here: https://github.com/slusarz/dovecot-fts-flatcurve/issues/66 I have to following panic with fts flatcurve enabled: ``` Panic: file index-search-result.c: line 132 (index_search_result_update_flags): assertion failed: (result->search_args->args == &search_arg) Error: Raw backtrace: /usr/lib/dovecot/libdovecot.so.0(backtrace_append+0x46) [0x74e9890a2846] -> /usr/lib/dovecot/libdovecot.so.0(backtrace_get+0x22) [0x74e9890a2962] -> /usr/lib/dovecot/libdovecot.so.0(+0x10d81b) [0x74e9890af81b] -> /usr/lib/dovecot/libdovecot.so.0(+0x10d8b7) [0x74e9890af8b7] -> /usr/lib/dovecot/libdovecot.so.0(+0x5e2e2) [0x74e9890002e2] -> /usr/lib/dovecot/libdovecot-storage.so.0(+0x518a4) [0x74e9891d38a4] -> /usr/lib/dovecot/modules/lib20_virtual_plugin.so(virtual_storage_sync_init+0x274e) [0x74e988bf8a9e] -> /usr/lib/dovecot/libdovecot-storage.so.0(mailbox_sync_init+0x5c) [0x74e9891eff9c] -> /usr/lib/dovecot/libdovecot-storage.so.0(mailbox_sync+0x39) [0x74e9891f0039] -> dovecot/imap(cmd_select_full+0x1df) [0x62354bd8326f] -> dovecot/imap(command_exec+0xa4) [0x62354bd8b444] -> dovecot/imap(+0x22392) [0x62354bd89392] -> dovecot/imap(+0x22444) [0x62354bd89444] -> dovecot/imap(client_handle_input+0x1bd) [0x62354bd8989d] -> dovecot/imap(client_input+0x74) [0x62354bd89e64] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x6d) [0x74e9890c603d] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x13a) [0x74e9890c77aa] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x54) [0x74e9890c60e4] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_run+0x40) [0x74e9890c62a0] -> /usr/lib/dovecot/libdovecot.so.0(master_service_run+0x17) [0x74e989036ad7] -> dovecot/imap(main+0x570) [0x62354bd7ad20] -> /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x74e988c29d90] -> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x74e988c29e40] -> dovecot/imap(_start+0x25) [0x62354bd7ade5] ``` It happens when accessing virtual folder with filters like this: ``` something-*/excep-dev* header x-abc-exception "1" ``` The error happens on subsequent access of the folder: - Removing dovecot.index{,.log} files allows to access the virtual folder again - dovecot.index gets recreated on access and the folder can be accessed multiple times - Marking an e-mail read triggers the error, though! Now each next access raises the error - Removing dovecot.index{,.log} restores access again and the e-mails are still marked as read (so this information is not lost), until the next e-mail is marked as read: then the folder cannot be accessed again Slusarz debugged the backtrace and wrote a detailed description at https://github.com/slusarz/dovecot-fts-flatcurve/issues/66#issuecomment-229… which I'll quote here: > This is not a flatcurve bug - it is a bug within Dovecot's indexing/fts handling. > > (Detailed debug below, so that core team can understand the problem.) > > As discussed above, this bug is triggered with virtual mailboxes on subsequent accesses. The initial access will work fine; the assert crash only happens when the Dovecot lib-storage index code reads the indexes created for the virtual mailboxes. > > `index_search_result_update_appends()` in lib-storage/index/index-search-result.c > > * Inside this function, a "temporary search parameter to limit the search only to the new messages" is added to the mail search args. Later, it is checked that the mail_search args points to this same search parameter after the search is executed. It is this assert check that is failing, because the mail args is changing during the course of the search. > > * `i_assert(result->search_args->args == &search_arg);` > > > The search args are being altered in plugins/fts/fts-search.args.c, `fts_search_args_expand()`. Specifically, in that function, either `fts_search_args_expand_language_top_level()` or `fts_search_args_expand_tree()` is being called, which can replace the current args parameter with a new pointer. > > `fts_search_args_expand()` is being called in plugins//fts/fts-search.c by `fts_search_try_lookup()` when the FTS backend has the FTS_BACKEND_FLAG_TOKENIZED_INPUT flag set. Flatcurve has this flag set. > > This flag is defined in plugins/fts/fts-api-private.h. Comments say: > > ``` > /* Tokenize all the input. update_build_more() will be called a single > directly indexable token at a time. Searching will modify the search > args so that lookup() sees only tokens that can be directly > searched. */ > ``` > > Thus, the comments explicitly say the search args will be modified if this flag is set. This modification is incompatible with the assert check in `index_search_result_update_appends()`, which requires that the search args not be modified. > > The core team will have to determine whether this behavior is correct, or if the assert check is invalid. You can find some more discussion at https://github.com/slusarz/dovecot-fts-flatcurve/issues/66, but I think the most important part (the very detailed analysis from Slusarz, thanks again!) might be enough to understand and maybe fix the problem. Relevant information about the mail system: ``` # 2.3.21 (47349e2482): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.21 (f6cd4b8e) # OS: Linux 6.5.0-45-generic x86_64 Ubuntu 22.04.4 LTS [...] namespace { location = virtual:~/virtual:LAYOUT=maildir++ prefix = _/ separator = / } [...] plugin { acl = vfile acl_shared_dict = file:/var/lib/dovecot/db/shared fts = flatcurve fts_autoindex = yes fts_filters = normalizer-icu snowball stopwords fts_filters_en = lowercase snowball stopwords fts_languages = de en fts_tokenizer_email_address = maxlen=100 fts_tokenizer_generic = algorithm=simple maxlen=30 fts_tokenizers = generic email-address sieve = file:~/sieve;active=~/.dovecot.sieve } [...] ``` I can provide more information if you need. Thanks for looking into it!

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Segfault (null pointer dereference) in mail_index_unset_fscked
by Марк Коренберг 31 Oct '25

31 Oct '25

Dovecot 2.3.21.1 (d492236fa0) Reduced sources: int mdbox_storage_rebuild(struct mdbox_storage *storage) { struct mdbox_map_atomic_context *atomic; atomic = mdbox_map_atomic_begin(storage->map); mdbox_map_atomic_unset_fscked(atomic); <---- atomic here is NULL according to gdb bt } struct mdbox_map_atomic_context *mdbox_map_atomic_begin(struct mdbox_map *map) { struct mdbox_map_atomic_context *atomic; atomic = i_new(struct mdbox_map_atomic_context, 1); atomic->map = map; <------- would fall here if atomic was NULL. but it does not. return atomic; } Seems memory corruption happens somewhere. Happy to help if you say how. -------------- Some tracebacks: #0 mail_index_unset_fscked (t=0x0) at ../lib-index/mail-index-transaction-update.c:1331 #1 0x00007fb99b0b1eb0 in mdbox_storage_rebuild (storage=<optimized out>) at index/dbox-multi/mdbox-storage-rebuild.c:1001 #2 0x00007fb99b0b2925 in mdbox_mailbox_close (box=0x56448dda4158) at index/dbox-multi/mdbox-storage.c:201 #3 0x00007fb99b08f3ba in mailbox_close (box=0x56448dda4158) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1642 #4 mailbox_close (box=box@entry=0x56448dda4158) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1633 #5 0x00007fb99b0946ef in mailbox_free (_box=_box@entry=0x7ffe965912a0) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1662 #6 0x0000564463d53a63 in imap_client_close_mailbox (client=client@entry=0x56448dd91ce8) ------ #0 mail_index_unset_fscked (t=0x0) at ../lib-index/mail-index-transaction-update.c:1331 #1 0x00007fed23455eb0 in mdbox_storage_rebuild (storage=<optimized out>) at index/dbox-multi/mdbox-storage-rebuild.c:1001 #2 0x00007fed23456925 in mdbox_mailbox_close (box=0x558f04a98ed8) at index/dbox-multi/mdbox-storage.c:201 #3 0x00007fed234333ba in mailbox_close (box=0x558f04a98ed8) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1642 #4 mailbox_close (box=box@entry=0x558f04a98ed8) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1633 #5 0x00007fed234386ef in mailbox_free (_box=_box@entry=0x7ffc98e15758) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1662 #6 0x00007fed22a4b2fc in quota_count_mailbox (root=0x558f04a73700, ns=0x558f04a4c7d0, vname=0x7fed23523807 "INBOX", bytes=<optimized out>, ------------- #0 mail_index_unset_fscked (t=0x0) at ../lib-index/mail-index-transaction-update.c:1331 #1 0x00007f8b661a2eb0 in mdbox_storage_rebuild (storage=<optimized out>) at index/dbox-multi/mdbox-storage-rebuild.c:1001 #2 0x00007f8b661a3925 in mdbox_mailbox_close (box=0x55690db6dec8) at index/dbox-multi/mdbox-storage.c:201 #3 0x00007f8b661803ba in mailbox_close (box=0x55690db6dec8) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1642 #4 mailbox_close (box=box@entry=0x55690db6dec8) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1633 #5 0x00007f8b661856ef in mailbox_free (_box=<optimized out>) at /usr/src/debug/dovecot-2.3.21.1-1.fc41.x86_64/src/lib-storage/mail-storage.c:1662 #6 0x00007f8b657a72fc in _Unwind_SetGRValue (context=<optimized out>, index=229799824, val=161) at ../../../libgcc/unwind-dw2.c:329 ------------ -- Segmentation fault

5 10

dovecot-2.4.2 pigeonhole make check failure
by Eray Aslan 31 Oct '25

31 Oct '25

Running make check for pigeonhole-2.4.2 fails: $ ./configure --with-dovecot=../dovecot-2.4.2 --with-managesieve \ && make \ && make check [...] make[2]: Leaving directory '/tmp/dovecot/dovecot-pigeonhole-2.4.2/doc' make[1]: Leaving directory '/tmp/dovecot/dovecot-pigeonhole-2.4.2/doc' /bin/sh ./update-version.sh . . testsuite: Fatal: execv(/usr/local/bin/doveconf) failed: No such file or directory make: *** [Makefile:1261: tests/testsuite.svtest] Error 84 This seems to be the result of commit 8b9295d. Do we now require a dovecot installation (or at least a working doveconf binary) for running tests for pigeonhole or is there a workaround I am missing? Thank you -- Eray

1 1

Dovecot and Pigeonhole v2.4.2 released
by Aki Tuomi 31 Oct '25

31 Oct '25

Hi! We are pleased to release version 2.4.2 of Dovecot and Pigeonhole. Important notice that we are adding new dependency of libpcre2 in this release to implement support for regular expressions in more safe manner. This release adds support for Debian Trixie and Red Hat Enterprise Linux 10, and removes support for Debian Bullseye and Red Hat Enterprise Linux 8. https://dovecot.org/releases/2.4/dovecot-2.4.2.tar.gz https://dovecot.org/releases/2.4/dovecot-2.4.2.tar.gz.sig https://pigeonhole.dovecot.org/releases/2.4/dovecot-pigeonhole-2.4.2.tar.gz https://pigeonhole.dovecot.org/releases/2.4/dovecot-pigeonhole-2.4.2.tar.gz… Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot -- Dovecot NEWS * CVE-2025-30189: Passdb oauth2 (not oauth2 mechanism), passdb passwd, passdb bsdauth, and userdb passwd drivers would cause users to be cached with same cache key when auth cache was enabled. * auth: Remove proxy_always field. * config: Change settings history parsing to use python3. * doveadm: Print table formatter - Print empty values as "-". * imapc: Propagate remote error codes properly. * lda: Default mail_home=$HOME environment if not using userdb lookup * lib-dcrypt: Salt for new version 2 keys has been increased to 16 bytes. * lib-dregex: Add libpcre2 based regular expression support to Dovecot, if the library is missing, disable all regular expressions. This adds libpcre2-32 as build dependency. * lib-oauth2: jwt - Allow nbf and iat to point 1 second into future. * lib: Replace libicu with our own unicode library. Removes libicu as build dependency. * login-common: If proxying fails due to remote having invalid SSL cert, don't reconnect. + auth: Add ssl_client_cert_fp and ssl_client_cert_pubkey_fp fields, see https://doc.dovecot.org/latest/core/summaries/settings.html#ssl_peer_certif… for more information. + config: Add support for $SET:filter/path/setting. + config: Improve @group includes to work with overwriting their settings. + doveadm kick: Add support for kicking multiple usernames + doveadm mailbox status: Add support for deleted status item. + imap, imap-client: Add experimental partial IMAP4rev2 support. + imap: Implement support for UTF8=ACCEPT for APPEND + lib-oauth2, oauth2: Add oauth2_token_expire_grace setting. + lmtp: lmtp-client - Support command pipelining. + login-common: Support local/remote blocks better. + master: accept() unix/inet connections before creating child process to handle it. This reduces timeouts when child processes are slow to spawn themselves. - SMTPUTF8 was accepted even when it wasn't enabled. - auth, *-login: Direct logging with -L parameter was not working. - auth: Crash occured when OAUTH token validation failed with oauth2_use_worker_with_mech=yes. - auth: Invalid field handling crashes were fixed. - auth: ldap - Potential crash could happen at deinit. - auth: mech-gssapi - Server sending empty initial response would cause errors. - auth: mech-winbind - GSS-SPNEGO mechanism was erroneously marked as not accepting NUL. - config: Multiple issues with $SET handling has been fixed. - configure: Building without LDAP didn't work. - doveadm: If source user didn't exist, a crash would occur. - imap, pop3, submission, imap-urlauth: USER environment usage was broken when running standalone. - imap-hibernate: Statistics would get truncated on unhibernation. - imap: "SEARCH MIMEPART FILENAME ENDS" command could have accessed memory outside allocated buffer, resulting in a crash. - imapc: Fetching partial headers would cause other cached headers to be cached empty, breaking e.g. imap envelope responses when caching to disk. - imapc: Shared namespace's INBOX mailbox was not always uppercased. - imapc: imapc_features=guid-forced GUID generation was not working correctly. - lda: USER environment was not accepted if -d hasn't been specified. - lib-http: http-url - Significant path percent encoding through parse and create was not preserved. This is mainly important for Dovecot's Lua bindings for lib-http. - lib-settings: Crash would occur when using %variables in SET_FILE type settings. - lib-storage: Attachment flags were attempted to be added for readonly mailboxes with mail_attachment_flags=add-flags. - lib-storage: Root directory for unusable shared namespaces was unnecessarily attempted to be created. - lib: Crash would occur when config was reloaded and logging to syslog. - login-common: Crash might have occured when login proxy was destroyed. - sqlite: The sqlite_journal_mode=wal setting didn't actually do anything. - Many other bugs have been fixed. -- Pigeonhole NEWS * lib-sieve: Use new regular expression library in core. * managesieve: Add default service_extra_groups=$SET:default_internal_group. + lib-sieve: Add support for "extlists" extension. + lib-sieve: regex - Allow unicode comparator. - lib-sieve-tool: sieve-tool - All sieve_script settings were overriden. - lib-sieve: storage: dict: sieve_script_dict filter was missing from settings. - sieve-ldap-storage: Fix compile without LDAP.

4 4

dovecot-2.4.2 lua5-1 build failure
by Eray Aslan 31 Oct '25

31 Oct '25

Hi, Building dovecot-2.4.2 fails to build against lua5-1: $ ./configure --with-lua [...] checking for lua5.1 >= 5.1 lua5.1 != 5.2... yes configure: using library lua5.1 checking for lua_newstate... yes checking for luaL_setfuncs... no checking for luaL_setmetatable... no checking for lua_isinteger... no checking for lua_resume... yes checking for lua_seti... no checking for lua_tointegerx... no checking for lua_yieldk... no [...] $ make [...] CC dlua-iostream.lo dlua-iostream.c:16:28: error: field 'stream' has incomplete type 16 | struct luaL_Stream stream; | ^~~~~~ dlua-iostream.c: In function 'dlua_o_write': dlua-iostream.c:68:24: error: implicit declaration of function 'luaL_tolstring'; did you mean 'lua_tolstring'? [-Wimplicit-function-declaration] 68 | vec.iov_base = luaL_tolstring(L, 2, &vec.iov_len); | ^~~~~~~~~~~~~~ | lua_tolstring dlua-iostream.c:68:22: error: assignment to 'const void *' from 'int' makes pointer from integer without a cast [-Wint-conversion] 68 | vec.iov_base = luaL_tolstring(L, 2, &vec.iov_len); | ^ dlua-iostream.c:73:24: error: implicit declaration of function 'luaL_fileresult'; did you mean 'luaL_pushresult'? [-Wimplicit-function-declaration] 73 | return luaL_fileresult(L, 0, o_stream_get_name(stream->os)); | ^~~~~~~~~~~~~~~ | luaL_pushresult make[3]: *** [Makefile:786: dlua-iostream.lo] Error 1 Same configure and make commands succeed when run against lua5-4. Not sure if this was intentional as we still check for >= lua5-1 != lua5-2 in m4/want_lua.m4 Thanks -- Eray

2 1

dovecot_config_version 2.4.2 -> error
by Genes Lists 30 Oct '25

30 Oct '25

Hi I would expect this to track the current version (i.e. 2.4.2) - would be good to accept 2.4.2 and later versions as they are released: doveconf line 9: Invalid dovecot_config_version: Currently supported versions are: 2.4.0 2.4.1 0.0.0 -- Gene

3 13

USER_PASSWORD environment variable
by Hendrik Friedel 30 Oct '25

30 Oct '25

Hello, can you tell me, where to find documentation on the USER_PASSWORD environment variable? I do not find how to specify more than one user. Thanks and best regards, Hendrik

2 1

lmtp server disconnects upon "RCPT TO" with internal error message
by rmfuhrer＠optonline.net 30 Oct '25

30 Oct '25

I've got a dovecot 2.4.1 instance (from the DockerHub official image) in a test Docker container on MacOS, running both IMAPS and LMTP. The IMAPS service is behaving normally, including the SSL negotiation, so I'm sure my cert (from LetsEncrypt) are kosher. I want to use fetchmail to deliver emails via LTMP, and fetchmail seems to connect to LMTP but doesn't succeed in delivering any emails. I tried the following experiment to manually craft an mail-delivery interaction with LMTP, but the connection suddenly closed right after the server sees the "RCPT TO", with an odd internal SSL error: $ openssl s_client -showcerts -connect 127.0.0.1:31024 ... <SSL negotiation diagnostics> ... Secure Renegotiation IS NOT supported ... 220 104b6de64916 Dovecot ready. LHLO test.mydomain.net 250-104b6de64916 250-8BITMIME 250-CHUNKING 250-ENHANCEDSTATUSCODES 250-PIPELINING 250 SMTPUTF8 MAIL FROM:<someuser(a)somedomain.net> 250 2.1.0 OK RCPT TO:<myuser(a)mydomain.net> RENEGOTIATING 8204750656:error:1404C042:SSL routines:ST_OK:called a function you should not call:/AppleInternal/Library/BuildRoots/4ff29661-3588-11ef-9513-e2437461156c/Library/Caches/com.apple.xbs/Sources/libressl/libressl-3.3/ssl/ssl_lib.c:2435: $ Note that during SSL negotiation, the client notes that "Secure Renegotiation IS NOT supported". Not sure whether that's relevant, but I do see "RENEGOTIATING" just before the fatal (?) error. FWIW, the recipient "myuser(a)mydomain.net" really exists on the Dovecot server; I have a mail client that connects to the IMAP service and successfully authenticates as that user. The relevant LMTP portion of the Dovecot logs looks like this: Oct 29 14:02:38 lmtp(7270): Info: Connect from 192.168.65.1 Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x10, ret=1: before SSL initialization Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: before SSL initialization Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2002, ret=-1: before SSL initialization Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: before SSL initialization Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS read client hello Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS write server hello Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS write change cipher spec Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: TLSv1.3 write encrypted extensions Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS write certificate Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: TLSv1.3 write server certificate verify Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS write finished Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: TLSv1.3 early data Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2002, ret=-1: TLSv1.3 early data Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2002, ret=-1: TLSv1.3 early data Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2002, ret=-1: TLSv1.3 early data Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2002, ret=-1: TLSv1.3 early data Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: TLSv1.3 early data Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS read finished Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x20, ret=1: SSLv3/TLS write session ticket Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS write session ticket Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2001, ret=1: SSLv3/TLS write session ticket Oct 29 14:02:38 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL: where=0x2002, ret=1: SSL negotiation finished successfully Oct 29 14:03:14 lmtp(7270): Debug: lmtp-server: conn 192.168.65.1:36620 [1]: SSL alert: close notify Oct 29 14:03:14 lmtp(7270): Info: Disconnect from 192.168.65.1: Connection closed (state=MAIL FROM) I've searched around and not found anything useful (in fact, hardly anything at all) about the above-cited error. Clues, anyone?

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