December 2020 - dovecot

ulimit -n vs client_limit vs process_limit
by Joseph Tam 19 Dec '20

19 Dec '20

As many of my users are accessing their mail remotely, I've seen service loads increase and came across this log messages which I haven't seen before imap-login: Error: socketpair() failed: Too many open files: user=<*>, ... I gather I have to increase file descriptor limits, which is currently set to match default_client_limit = 1000 What should I set "ulimit -n" relative to client_limit? Or perhaps I've roofed service imap-login { process_limit = 2 ... } and should adjust that? Joseph Tam <jtam.home(a)gmail.com>

3 3

Dovecot Replication Errors (only) when using tcps: as the mail_replica Protocol
by Reuben Farrelly 18 Dec '20

18 Dec '20

Hi, I've been seeing errors logged for some time with replication processes, whereby replication sessions seem to be timing out periodically. This is with dovecot version 2.3.10.1 (a3d0e1171) and both are Gentoo x86_64. After some investigation I've determined that these timeouts are only ever occurring with tcps as the replication connection type. These errors never occur if non-encrypted tcp is configured. I've been able to validate this by changing only the replica_type on both ends of the replication configuration to tcp, and with no other changes and after a few days of operation there is not a single error logged. mail_replica = tcps:lightning.reub.net:4813 <<< periodic timeouts mail_replica = tcp:lightning.reub.net:4814 <<< works perfectly Example of the error: Jun 12 15:45:44 thunderstorm.reub.net dovecot[21149]: dsync-local(kaylene)<zx+WKTAU416UMwAAzkCIew>: Error: dsync(lightning.reub.net): I/O has stalled, no activity for 600 seconds (last sent=mailbox_delete, last recv=handshake) Jun 12 15:45:44 thunderstorm.reub.net dovecot[21149]: dsync-local(kaylene)<zx+WKTAU416UMwAAzkCIew>: Error: Timeout during state=recv_mailbox_tree doveadm: Error: Timeout during state=slave_recv_mailbox: 6 Time(s) doveadm: Error: Timeout during state=sync_mails (send=mail_requests recv=attributes): 31 Time(s) doveadm: Error: dsync(thunderstorm.reub.net): I/O has stalled, no activity for 600 seconds (last sent=mail_change (EOL), last recv=mailbox): 31 Time(s) doveadm: Error: dsync(thunderstorm.reub.net): I/O has stalled, no activity for 600 seconds (last sent=mailbox_delete, last recv=mailbox_delete): 6 Time(s) It is seen on both sides of the replication setup. The replica is offsite but only a few ms of latency away and there is no packet loss. The replication is happening over IPv6, and the local firewall is logging that sessions are always permitted, and only ever finishing due to tcp-fin or tcp-rst-from-client . SSL appears to be correctly configured, and it seems that the replication itself is for the most part working. Clients are able to use imaps just fine so I don't think there's anything much wrong from an SSL perspective else I'd be seeing complete replication failure and/or client devices unable to connect. Can anyone suggest how we can further debug this problem? Thanks, Reuben

4 3

Outlook with Dovecot
by Elise 17 Dec '20

17 Dec '20

dovecot-2.3.11.3_1 Hi group, I have a problem with connecting Outlook 2019 client to my server (BSD 21.2). Running Postfix and Dovecot. [all.log] Dec 12 16:53:41 poseidon dovecot[36185]: imap-login: Disconnected (auth failed, 1 attempts in 2 secs): user=<elise(a)xxxxx.xx>, method=PLAIN, rip=82.x.x.x.x, lip=10.x.x.x, TLS: Connection closed, session=<U62faUa24N5SsH9H> Providing the correct email address and password. Strang thing is that with Thunderbird it all works fine; only Outlook is refused. tx, Elise [dovecot.conf] auth_mechanisms = plain login disable_plaintext_auth = no mail_location = mbox:/usr/home/%u:INBOX=/var/mail/%u mail_privileged_group = mail passdb { driver = pam } protocols = imap service auth { unix_listener auth-client { group = mail mode = 0660 user = postfix } unix_listener auth-master { mode = 0666 } user = root } service imap-login { inet_listener imap { address = 10.x.x.x } inet_listener imaps { address = 10.x.x.x } } #service pop3-login { # inet_listener pop3 { # address = 10.x.x.x # } # inet_listener pop3s { # address = 10.x.x.x # } #} ssl = yes ssl_ca = </usr/local/share/certs/ca-root-nss.crt ssl_cert = </usr/local/etc/dehydrated/certs/xxxx.xxx/fullchain.pem ssl_key = </usr/local/etc/dehydrated/certs/xxxx.xxx/privkey.pem ssl_cipher_list = HIGH:+TLSv1.2:+TLSv1.3 ssl_dh = </usr/local/etc/dovecot/dh.pem userdb { driver = passwd } protocol imap { imap_client_workarounds = "delay-newmail tb-extra-mailbox-sep " } #protocol pop3 { # pop3_client_workarounds = outlook-no-nuls oe-ns-eoh # pop3_uidl_format = %08Xu%08Xv #} protocol lda { postmaster_address = postmaster(a)xxxxx.xxxx sendmail_path = /usr/sbin/sendmail mail_plugins = sieve }

7 11

Special files under dovecot mail box
by hfh＠cndns.com 17 Dec '20

17 Dec '20

Hello, even if all the mails(messages) are deleted from my mail box (such as the sent box), the capacity of the following special files will not change, that is, these files will only increase and easily occupy the disk. Is there any other way besides using doveadm index manually? In addition, will these files be affected if they are deleted? -rw-------. 1 vmail vmail 3912 Dec 1 13:52 dovecot.index -rw-------. 1 vmail vmail 127008 Dec 17 17:21 dovecot.index.cache -rw-------. 1 vmail vmail 18800 Dec 17 17:21 dovecot.index.log -rw-------. 1 vmail vmail 1567 Jun 20 2019 dovecot.index.thread Dovecot version is 2.2.36.

1 0

Disallow acces via imap, but keep lmtp running
by Julian Kippels 16 Dec '20

16 Dec '20

Hi all, what is the best way to temporarily disable access to a mailbox via imap, but keep it possible to deliver to the mailbox via lmtp? I want to migrate some mailboxes around and would like to ensure that the users cannot access their mail while doing so. I would like to keep the users from logging in entirely rather than setting ACLs. Thanks in advance Julian

5 4

Re: Disallow acces via imap, but keep lmtp running
by Julian Kippels 16 Dec '20

16 Dec '20

I thought about that, but that would also kill their access to wifi and other services, because it all comes from the same LDAP. Julian Am Tue, 15 Dec 2020 23:37:58 +0100 schrieb Jos <jos(a)cloudzeeland.nl>: > You could change their password temporily and do the migration? > > — Verstuurd via een mobiele telefoon > > > Op 15 dec. 2020 om 23:22 heeft Julian Kippels <kippels(a)hhu.de> het > > volgende geschreven: > > > > Hi all, > > > > what is the best way to temporarily disable access to a mailbox via > > imap, but keep it possible to deliver to the mailbox via lmtp? > > I want to migrate some mailboxes around and would like to ensure > > that the users cannot access their mail while doing so. > > I would like to keep the users from logging in entirely rather than > > setting ACLs. > > > > Thanks in advance > > Julian

3 2

Dovecot Director scaling / performance
by tim＠linux-daus.de 15 Dec '20

15 Dec '20

Hi, currently i'm going to evaluate the Dovecot Director. Are there someone with experience how the Dovecot Director does scale? The last current information i could find was a post on this mailing list from 2012: 4 Directors are well known, >75 are too much. Are there any more up to date experience regarding how many user (current and new/s) a single Dovecot Director/proxy node could handle and how many director nodes in a ring are known to work (well)? Best regards, Tim

2 1

Putting UIDL value into X-UIDL: header
by Süleyman Düzdaban 15 Dec '20

15 Dec '20

Hi, Is there any way to put UIDL value into X-UIDL: header with Dovecot or Sieve? As stated in https://wiki2.dovecot.org/Migration page QPopper can do that. I'm asking this for preventing clients who are using POP to re-download messages and making future migrations easy. I can really benefit from inserting UIDL values even only for the new messages from now on, but if there is any way to put it into all messages in all mailboxes (Maildir) I would be grateful for that too. Dovecot version: 2.3.8 (9df20d2db) Thanks in advance.

3 4

How to reset / remove all replicator users
by Ralf Becker 14 Dec '20

14 Dec '20

After creating a new replication pair, it was started with an old sqlite userdb, we use for iteration / replication. The situation was quickly resolved by generating a new sqlite userdb, as it is done hourly anyway. Unfortunately I can not get ride of all access users from the replication: / # doveadm replicator status Queued 'sync' requests 0 Queued 'high' requests 0 Queued 'low' requests 0 Queued 'failed' requests 0 Queued 'full resync' requests 14 Waiting 'failed' requests 1 Total number of known users 724 / # doveadm user '*'|wc -l 507 The replication process creates again and again a lot (empty) mailboxes on both sides of the replication. I tried the obvious with no avail: / # doveadm replicator remove '*' Error: Replicator failed: User not found I also tried restarting the pair one after the other, but it seems the users to replicate are somewhere persisted. I'm also trying to delete the users from the newly created (empty) mailboxes, but the number of known users in "doveadm replicator status" is unchanged: root:/var/dovecot/imap# for domain in $(ls -1 |grep -v bb-trunk.egroupware.de|grep -v outdoor-training.de|grep -v rbz-); do for user in $domain/*; do echo "$(basename $user)@$domain"; doveadm replicator remove "$(basename $user)@$domain"; done; rm -rf $domain; done Any idea what else I can do, or where the replication stores it's users? Ralf -- Ralf Becker EGroupware GmbH [www.egroupware.org] Handelsregister HRB Kaiserslautern 3587 Geschäftsführer Birgit und Ralf Becker Leibnizstr. 17, 67663 Kaiserslautern, Germany Telefon +49 631 31657-0

2 1

How to setup Dovecot director in a NAT-like environment?
by Richard Mader 14 Dec '20

14 Dec '20

How can I setup Dovecot director in a NAT like environment? My mailservers are running within docker and one of them behind a router, so the IP that dovecot binds to does not match the IP that other mailservers have to use to connect to them. Since when running director the servers connect to each other, I'd guess I'd have to set the external IP of the servers in the "director_servers". If I do that I'm unable to start the director nodes since they cannnot find out which of the addresses is their own. I had a quick peek at the sourcecode and director detects its own address by trying to bind to all of the addresses. Since we're behind a NAT, that will of course fail for its external IP. When I set the local address or localhost in the "director_servers" directive, then the director nodes are able to start but they are denied when connecting to other nodes. When using the NAT-internal IP I've got the following error: > Error: Remote director thinks it's someone else (connected to > <other-directors-external-ip>:9090, remote says it's > <other-directors-internal-ip>:9090) When using localhost/127.0.0.1 then I get: > Info: Connecting to <other-directors-external-ip>:9090 (as 127.0.0.1): > Alone in director ring - trying to connect to others > Error: connect(<other-directors-external-ip>:9090) failed: Invalid > argument Is it somehow possible to tell director which of the addresses within "director_servers" is its own address, that it then advertises to other servers, instead of trying figuring that out itself by trying to bind to all ip-addresses on startup? Kafka e.g. has the "advertised.listeners" property to set a custom host to announce to clients and to other Kafka nodes. If there is not such a property or any other workaround, I might consider implementing this into director myself. Although I might need some help getting started since this is my first time contributing to a non Scala/Java or Typescript/NodeJS Project. So far I've discovered that Github seems to be the official repo and is not just a mirror and I was able to compile it on my machine. Now I've got questions such as, where can I find the binaries that I've just compiled and whats the best way to get them running locally and to test my changes, where are unit tests located, ...? Best Regards, Richard

2 1