- dovecot - dovecot.org

Re: "Connection reset by peer" errors with Outlook
by Joseph Tam 24 Jan '24

24 Jan '24

From: Steve Dondley <s(a)dondley.com> > I have no idea what is triggering it for so many different users from legit > email addresses. Still investigating. But this appears to be a fail2ban > problem, not a dovecot problem. My logs are filled with failed authentication from Outlook clients. The clients seem to be trying different usernames (with/without domains), and maybe SSL/TLS flavours. My guess is Outlook is doing some autodiscovery/autoconfiguration thing, and occasionally hits the right combo and successfully authenticates. I'm not sure I would characterise this as a fail2ban problem. Fail2ban is doing what it says on the side of the tin: looking for repeated authentication failures, and blocking those that fail too many times. The real problem is Outlook fumble around for the correct settings, and mimicking a brute force attack. I've had great difficulty getting some Outlook clients to configure exactly the settings it should have (like excluding domain names from usernames). Try running his command line using Windows-R (not from cmd.exe). outlook.exe /PIM NoEmail This will avoid the auto-setup process that railroads you into frustration. MacOSX Mail app tries the same stuff, but at least you can turn that behaviour off and stop it from second guessing your settings. Joseph Tam <jtam.home(a)gmail.com>

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Managesieve "config" unable to complete?
by joe a 24 Jan '24

24 Jan '24

What say we try this again, on a "blank slate"? Dovecot installed on OpenSuse Leap 15.5, from their supplied "dovecot23" package. That package claims to be Dovecot 2.3.21 and Pigeonhole 0.5.21 Unable to get managesieve to bind to port 4190. Output of dovecot -n attached. Various tools, including lsof, sockets, do not show 4190 in use. While grasping for/at straws, noticed this: ~: # lsof | grep manage config 19097 root mem REG 0,47 6896 257261 /usr/lib64/dovecot/modules/settings/libmanagesieve_settings.so config 19097 root mem REG 0,47 14696 257260 /usr/lib64/dovecot/modules/settings/libmanagesieve_login_settings.so Does that suggest an attempt to configure managesieve is unable to do so? What does it infer? Bad configuration? File ownership? File rights? Bug? Thanks for patience and forbearance

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Strangeness in defining "protocols"
by joe a 24 Jan '24

24 Jan '24

Well, a strangeness to my view. Since this is an opensuse package and not the "lastest and greatest", not sure if I should post this here or "over there". It is a given that I may have, through some noobiness have bungled something early on that is causing this. I am prepared to accept the semi-public ritual shaming that may follow. All references to results mean per "dovecot -n". One can be assured that dovecot.conf was edited followed by "dovecot -n", then 20-managesieve.conf edited followed by "dovecot -n", for each "set". What happens is, it appears, that if one specifies or alters the "default" protocols in /etc/dovecot/dovecot.conf, any protocols subsequently defined, at least in /etc/dovecot/conf.d/20-managesieve.conf, are not honored. It does not seem to matter if it is specified as "protocols = sieve" or "protocols = $protocols sieve". Further, in /etc/dovecot/dovecot.conf, if one comments out "protocols", one finds protocols is not listed at all, unless there is a protocol defined later such as "sieve" in 20-managesieve.conf. if one lists "protocols = " then "protocols = " is listed even if a protocol is defined later such as "sieve" in 20-managesieve.conf of one lists "protocols = $protocols", nothing is listed, unless if: "protocols = sieve" is defined in 20-managesieve.conf, "protocols = sieve" is listed "protocols = $protocols sieve" is defined in 20-managesieve.conf - then "protocols = imap pop3 lmtp sieve" is listed. Again, all as shown by "dovecot -n" after editing each file(s). I hope this is useful in determining if there is a problem, and helps lead to a solution if one is warranted. I'll send this also to the openSuse list as a distinct email.

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managesieve server not answering?
by Joe Acquisto 23 Jan '24

23 Jan '24

Trying to connect to managesieve server configured to port 4190. No go. Roundcube is configured (thunderbird apparently having nothing current), but selecting "Add Filter" (new since re-configured for managesieve) produces "unable to connect to server". Port 4190 does not seem to answer or be "bound" to anything. Telnet to 4190 produces "connection refused". A "one box" solution. If I had to guess, I would guess, operator error. Otherwise, things are looking up. But, I remember a movie that said never to do that . . .

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Replication between three or more servers
by tomas.simonaitis＠gmail.com 23 Jan '24

23 Jan '24

Hi list members, documentation says "Replication works only between server pairs. If you have a large cluster, you need multiple independently functioning Dovecot backend pairs". Do I understant correctly, that in order to have replication between 3 servers, one would need to run 2 instances of dovecot on each server with (a bit) different configuration. e.g. Serv1: -- dovecot-1.conf .. plugin { mail_replica = tcps:Serv2:1234 } .. -- dovecot-2.conf .. plugin { mail_replica = tcps:Serv3:1234 } .. Serv2: -- dovecot-1.conf .. plugin { mail_replica = tcps:Serv1:1234 } .. -- dovecot-2.conf .. plugin { mail_replica = tcps:Serv3:1234 } .. etc. Won't two processes of dovecot in one machine (assuming local storage) conflict accessing same Maildirs? Thanks for any insights

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doveadm http api not responding under load
by Achim Stahlberger 23 Jan '24

23 Jan '24

Hello, we see this problem when doveadm-server is under load. We enabled doveadm http api with this config: service doveadm { inet_listener { port = 50000 } inet_listener http { port = 50001 ssl = no } } When doveadm server receives at lot of connects on port 50000 the http service on port 50001 is not responding until load on port 50000 drops to zero. It seems like doveadm-server is prefering port 50000 over 50001. Looking into Recv-Q when http hangs Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp LISTEN 129 128 0.0.0.0:50000 0.0.0.0:* tcp LISTEN 1 128 0.0.0.0:50001 0.0.0.0:* I used this script to produce load on port 50000 #!/bin/bash for i in {1..1000} do echo "124" | netcat localhost 50000 & done wait When this script is started it takes several seconds until a connect on port 50001 succeeds. We are using Dovecot version 2.3.20 (bdc808f24c). I think the problem is in src/lib/ioloop-epoll.c function io_loop_handler_run_internal. This might fix the problem (look for new variable rr): void io_loop_handler_run_internal(struct ioloop *ioloop) { struct ioloop_handler_context *ctx = ioloop->handler_context; struct epoll_event *events; const struct epoll_event *event; struct io_list *list; struct io_file *io; struct timeval tv; unsigned int events_count; int msecs, ret, i, j, k, rr; bool call; i_assert(ctx != NULL); /* get the time left for next timeout task */ msecs = io_loop_run_get_wait_time(ioloop, &tv); events = array_get_modifiable(&ctx->events, &events_count); if (ioloop->io_files != NULL && events_count > ctx->deleted_count) { ret = epoll_wait(ctx->epfd, events, events_count, msecs); if (ret < 0 && errno != EINTR) i_fatal("epoll_wait(): %m"); } else { /* no I/Os, but we should have some timeouts. just wait for them. */ i_assert(msecs >= 0); i_sleep_intr_msecs(msecs); ret = 0; } /* execute timeout handlers */ io_loop_handle_timeouts(ioloop); if (!ioloop->running) return; rr = ret>1 ? i_rand_limit(ret) : 0; for (k = 0; k < 2; k++) { for (i = (k==0 ? rr : 0); i < (k==0 ? ret : rr); i++) { /* io_loop_handle_add() may cause events array reallocation, so we have use array_idx() */ event = array_idx(&ctx->events, i); list = event->data.ptr; for (j = 0; j < IOLOOP_IOLIST_IOS_PER_FD; j++) { io = list->ios[j]; if (io == NULL) continue; call = FALSE; if ((event->events & (EPOLLHUP | EPOLLERR)) != 0) call = TRUE; else if ((io->io.condition & IO_READ) != 0) call = (event->events & EPOLLIN) != 0; else if ((io->io.condition & IO_WRITE) != 0) call = (event->events & EPOLLOUT) != 0; else if ((io->io.condition & IO_ERROR) != 0) call = (event->events & IO_EPOLL_ERROR) != 0; if (call) { io_loop_call_io(&io->io); if (!ioloop->running) return; } } } } } Thanks a lot. Achim https://www.tallence.com Folgt uns auf LinkedIn <https://www.linkedin.com/company/tallence-ag> // XING <https://www.xing.com/pages/tallenceag> // Twitter <https://twitter.com/tallence> // Instagram <https://www.instagram.com/tallence_ag/> // facebook <http://www.facebook.com/Tallence> Tallence AG // Sitz der Gesellschaft: Hamburg // Neue Gröningerstraße 13, 20457 Hamburg // Amtsgericht Hamburg HRB 142900 Vorstand: Frank Moll (Vorsitzender), Bernd Scherf // Aufsichtsrat: Wolf Ingomar Faecks (Vorsitzender) Die Speicherung und Verarbeitung personenbezogener Daten erfolgt entsprechend unserer Datenschutzhinweise. <https://www.tallence.com/datenschutzhinweise>

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"Connection reset by peer" errors with Outlook
by Steve Dondley 23 Jan '24

23 Jan '24

I have a mail server using dovecot that has been running without issue for quite a couple of years now. It serves email for about 30 individuals. But since Jan 14th, users have been reporting spurious errors in MS Outlook: 316 Jan 21 00:38:12 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=783) failed: Connection reset by peer, session=<yVd4Hm4Pst12wSuN> 317 Jan 21 00:38:12 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=598) failed: Connection reset by peer, session=<aKOAHm4PCOB2wSuN> 318 Jan 21 00:38:13 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=598) failed: Connection reset by peer, session=<9rWIHm4PtuF2wSuN> 319 Jan 21 00:38:13 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=677) failed: Connection reset by peer, session=<NsORHm4P9OJ2wSuN> 320 Jan 21 00:38:14 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=691) failed: Connection reset by peer, session=<AACaHm4PdOR2wSuN> 321 Jan 21 00:38:15 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=610) failed: Connection reset by peer, session=<G8umHm4P2OV2wSuN> 322 Jan 21 00:38:16 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=609) failed: Connection reset by peer, session=<qSy0Hm4PuOd2wSuN> 323 Jan 21 00:38:16 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=596) failed: Connection reset by peer, session=<W427Hm4PtOl2wSuN> 324 Jan 21 00:38:17 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=596) failed: Connection reset by peer, session=<mu/JHm4Ptup2wSuN> Some characteristics of the problem that may offer a clue: * happening with multiple users, not just the same one * happens from different IP addresses. * happens about 3 to 5 times per day and the errors come in batches like above * MS Outlook error is: reported error (0x80042109): ‘Outlook cannot conect to your outgoing SMTP email server. If you continue to receive this message….blah blah blah I googled the error code but didn’t find anything particularly helpful. I’m running Debian bullseye, version 11.8.

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Migrate Dovecot 2.0.16 (mbox) to Dovecot 2.3.16 (MaiDir) and preserve POP UIDs
by Barbara M. 21 Jan '24

21 Jan '24

Already done a first migration using imapsync Good result, but there is the POP3 UIDs problem. Searching online give a Tried to understand the instructions on: https://doc.dovecot.org/settings/plugin/pop3-migration-plugin/? with limited comprension results (the link in the page is to the old wiki). Searching online give more confusion ... I am obviouly interested to resync the INBOX with somethig that give to clients the old UIDs so they don't re-download all messages in the inbox as duplicates into their mailbox. I suppose I can do: doveadm -v expunge -u <username> mailbox INBOX all rm dovecot* in the Maildir folder doveadm force-resync -u <username> INBOX then use dsync to migrate the INBOX Here I need some hints to how setup it and wich syntax use. If useful I can copy or mount the /var/mail/ folder of the old server that contains the users INBOX to the new server. Thanks, B.

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Re: Migrate Dovecot 2.0.16 (mbox) to Dovecot 2.3.16 (MaiDir) and preserve POP UIDs
by Joseph Tam 21 Jan '24

21 Jan '24

From: "Barbara M." <barbara(a)rfx.it> > I am obviouly interested to resync the INBOX with somethig that give to > clients the old UIDs so they don't re-download all messages in the inbox > as duplicates into their mailbox. When I mitigated away from qpopper, I configured protocol pop3 { ... pop3_reuse_xuidl = yes } Maybe that's of use to you? Joseph Tam <jtam.home(a)gmail.com>

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Uncompress compressed messages in Maildir mailbox?
by achekalin＠lazurit.com 21 Jan '24

21 Jan '24

Some time ago I enabled compression on incoming messages, so LMTP delivered messages were compressed. Good idea in terms of disk space, but now I cannot uncompress any of these messages even when I need to! I was using this setting: plugins { zlib_save = lz4 } and now I can see this string at the beginning of each message file - "Dovecot-LZ4", so no other software can uncompress them for me. Please advise, how can I uncompress message file in Maildir mailbox when I need to access its contents directly?

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