December 2015 - dovecot

Debug Dovecot Plugin (shared library)
by David Becher 24 Dec '15

24 Dec '15

Hey! I was just wondering what would be the best way to debug a plugin I am currently writing for dovecot. The plugin basically registers a new IMAP capability and I want to set a breakpoint to the "cmd_handle_new_capability" function (thats just a function name for better explaining purposes). Right now I have opened a connection via openssl ('openssl s_client -connect example:143 -starttls imap') to be able to mess around with the my server. Then I am able to login into the server via 'a login "username" "password"' and feed the server with my self created IMAP capability command. I know that I can start gdb and attach to an already running process via its PID. But how do I know which process I have to attach to? Looking at the output of 'top' it seems to be an instance of the 'imap' command PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 13413 vmail 20 0 21004 1844 1524 S 0.0 0.0 0:00.00 Iman But its only started the exact moment I issue my IMAP command towards the server, so of course I am not fast enough to track down the PID before the function has returned, so the process handling the command seems to be up only for the short period of time to handle the command, there is no process before which I can attach to. My current workaround is that I put a tail onto /var/log/mail.log and from within my shared library function (cmd_handle_new_capability) I log the PID of the current process, then sleep(10) for 10 seconds, which gives me enough time to have a look at mail.log to get to know the PID which I then can attach to. But isn't there a better way to do this? Maybe attach to the process which originally creates the new process handling the IMAP command and then stepping into it? I hope someone can help me out :) All the best, David

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Dovecot 2.2.20 autoexpunge
by Robert Blayzor 23 Dec '15

23 Dec '15

I have configured autoexpunge on some folders: namespace inbox { inbox = yes location = mailbox Junk { auto = subscribe autoexpunge = 30 days special_use = \Junk } mailbox Trash { auto = subscribe autoexpunge = 2 weeks special_use = \Trash } prefix = separator = / } After adding these and restarting, logging in and out several times, I still see messages days/weeks past the autoexpunge setting. I checked the logs but never see any autoexpunge messages logged. Is there something else that needs to be set to trigger this? -- Robert inoc.net!rblayzor XMPP: rblayzor.AT.inoc.net PGP Key: 78BEDCE1 @ pgp.mit.edu

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dsync and namespaces
by Charlie Hothersall-Thomas 22 Dec '15

22 Dec '15

`doveconf -n' output: > # 2.2.10: /etc/dovecot/dovecot.conf > # OS: Linux 3.10.0-229.20.1.el7.x86_64 x86_64 CentOS Linux release 7.2.1511 (Core) > listen = * > mail_location = maildir:~/Maildir/ > namespace { > inbox = yes > location = > prefix = > separator = / > type = private > } > namespace { > location = maildir:/srv/mail/ > prefix = Public/ > separator = / > subscriptions = no > type = public > } > passdb { > driver = pam > } > ssl_cert = </etc/pki/dovecot/certs/dovecot.pem > ssl_key = </etc/pki/dovecot/private/dovecot.pem > userdb { > driver = passwd > } I have some public mailboxes in /srv/mail -- Public/Alpha and Public/Mike -- using configuration taken more or less verbatim from http://wiki2.dovecot.org/SharedMailboxes/Public. These are stored in Maildir format; here's a sample of how things look on disk at the moment: > /srv/mail/ > ├── .Alpha > │ ├── cur > │ │ └── 1450775948.M24820P23708.cht,S=8186,W=8360:2,S > │ ├── dovecot.index.cache > │ ├── dovecot.index.log > │ ├── dovecot-uidlist > │ ├── maildirfolder > │ ├── new > │ └── tmp > ├── cur > ├── dovecot.index.log > ├── dovecot-uidlist > ├── dovecot-uidvalidity > ├── dovecot-uidvalidity.5679158d > ├── maildirfolder > ├── .Mike > │ ├── cur > │ │ ├── 1450775948.M202327P23708.cht,S=8405,W=8576:2,S > │ │ ├── 1450775948.M257575P23708.cht,S=5590,W=5732:2,S > │ ├── dovecot.index.cache > │ ├── dovecot.index.log > │ ├── dovecot-uidlist > │ ├── maildirfolder > │ ├── new > │ └── tmp > ├── new > └── tmp I'm trying to convert these public mailboxes from Maildir to mdbox format. My end goal is a directory structure like the following. I obtained this example by emptying /srv/mail, changing `location = maildir:/srv/mail/' to use mdbox, and then delivering some messages into Public/Alpha and Public/Mike: > /srv/mail/ > ├── dovecot-uidvalidity > ├── dovecot-uidvalidity.567915fa > ├── mailboxes > │ ├── Alpha > │ │ └── dbox-Mails > │ │ ├── dovecot.index.cache > │ │ └── dovecot.index.log > │ ├── dbox-Mails > │ │ └── dovecot.index.log > │ └── Mike > │ └── dbox-Mails > │ ├── dovecot.index.cache > │ └── dovecot.index.log > └── storage > ├── dovecot.map.index.log > └── m.1 I know that dsync can be used to convert between mailbox formats, but is this possible in conjunction with namespaces? I can convert one of my mailboxes to an arbitrary mdbox location on disk using... > dsync -o mail_location=mdbox:/tmp/dbox/ mirror maildir:/srv/mail/.Mike/ ... although this puts the messages inside an INBOX mailbox: > /tmp/dbox/ > ├── mailboxes > │ └── INBOX > │ └── dbox-Mails > │ ├── dovecot.index.cache > │ └── dovecot.index.log > └── storage > ├── dovecot.map.index.log > └── m.1 I could run this once per public mailbox, writing each to a different mdbox location, but am unaware of a method to merge them such that they would work with my Public/ namespace. Is it possible to use dsync to convert my public Maildir mailboxes to mdbox, resulting in my desired directory structure above? I think I want to be able to tell dsync the location as a mailbox name, rather than a disk location, although this doesn't appear to be possible. If not, is there another solution? My best idea at the moment is to make the configuration change and then re-deliver all messages by mailbox name. Thanks in advance, and happy holidays, -- Charlie Hothersall-Thomas | w: https://charlie.ht | e: me(a)charlie.ht | pgp: 4096R/C3676E3E

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[bug][Pigeonhole 0.4.10] Missing msgid
by Alexander Moisseev 22 Dec '15

22 Dec '15

Pigeonhole 0.4.10 doesn't log msgid for some messages. Dec 16 09:57:57 mx dovecot: lmtp(user1(a)example.com): EbLlL2gLcVYCBgEAPZa6/Q: sieve: msgid=<20151216065756.BE1DF1FFD8(a)cp.bitrix24.com>: forwarded to <user3(a)example.com> Dec 16 09:57:57 mx dovecot: lmtp(user1(a)example.com): EbLlL2gLcVYCBgEAPZa6/Q: sieve: stored mail into mailbox 'INBOX' Dec 16 09:57:57 mx dovecot: lmtp(user2(a)example.com): FrLlL2gLcVYCBgEAPZa6/Q: sieve: msgid=<20151216065756.C77BB1FFD8(a)cp.bitrix24.com>: forwarded to <user3(a)example.com> Dec 16 09:57:57 mx dovecot: lmtp(user2(a)example.com): FrLlL2gLcVYCBgEAPZa6/Q: sieve: msgid=<20151216065756.C77BB1FFD8(a)cp.bitrix24.com>: stored mail into mailbox 'bitrix'

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Where exactly are these Junk]Trash etc folders stored?
by Robert Chalmers 22 Dec '15

22 Dec '15

These folders are stored somewhere .. but where? mailbox Trash { auto = no special_use = \Trash } mailbox Drafts { auto = no special_use = \Drafts } mailbox Sent { auto = subscribe # autocreate and autosubscribe the Sent mailbox special_use = \Sent } mailbox "Sent Messages" { auto = no special_use = \Sent } mailbox Spam { auto = create # autocreate Spam, but don't autosubscribe special_use = \Junk } mailbox virtual/All { # if you have a virtual "All messages" mailbox auto = no special_use = \All }

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Thanks again for Dovecot
by Steve Litt 21 Dec '15

21 Dec '15

Hi all, All email clients suck. IMHO Claws-Mail sucks less, but even on the Claws-Mail mailing list there are all sorts of problems discussed. Most of these problems are a moot point for me, because I use Claws-Mail only as a window into my locally hosted Dovecot IMAP server. Claws-Mail is like a little window into Dovecot. Meanwhile, all those "don't quite work right" functionalities normally done by an email client I do outside of Claws. For filtering, I use Procmail, which sorts messages into the correct (Dovecot) folders and sends trolls to /dev/null. If Claws-Mail ever becomes as lame as Kmail, I can just switch to another email client, because most of my setup is in Dovecot and the input to Dovecot. Email clients are interchangeable for me, and this REALLY makes my life less worrysome. And Dovecot does one thing and does it right. It never breaks. Thank you for this great tool! SteveT Steve Litt November 2015 featured book: Troubleshooting Techniques of the Successful Technologist http://www.troubleshooters.com/techniques

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questions for a unusual master/slave like mail-server setup
by Christoph Anton Mitterer 21 Dec '15

21 Dec '15

Hey folks. I was planning since a long time for some more advanced mail server setup (described below), which basically has some weird ;) master/slave ideas behind. It's probably a bit more complicated (and maybe also a bit more insane) than the usual mail server setup, so I'd be happy about any advice and some questions answered: There are two mailservers (dovecot, as you may have guessed ;) ): - IMAP shall be used; using POP3 is not planned. - A format in which each mail is stored in a separate file shall be used. That leaves for either maildir or sdbox, where I'd prefer maildir, as I like to be able to loose the indexes. - Each (per user) mailbox shall have many subfolders and will receive loads of mail (including from several high traffic mailing lists). - Mail filtering shall take place *at least* on the "online" server, probably either with sieve or maildrop. - One of the mailservers is always "online", directly connected to the internet (and globally available). - The other mailserver is "offline", not directly connected to the internet (and only locally available). The "online" mailserver: - Is in a not fully trusted location (i.e. at some ISP). - Has somewhat limited storage. - Makes the mails on it available to MUAs connecting from anywhere. - Receives mail from various sources, e.g. via postfix/LDA or something like fetchmail. - Has only a parts of *all* mails, that means for example: - *All* mail from some personal contacts. - Only the last 1 year for low volume mailing lists. - Only the last 4 months for high volume mailing lists. The "offline" mailserver: - Is in a trusted location (beneath my pillow ;) ). - Has enough storage for the purposes of mail. - Makes all mails available to MUAs connecting from the LAN. - Receives mails from the "online" mailserver, when manually "moved" to it via some MUA over IMAP. - Has *all* mails. Client's MUAs, may connect to both, but the "offline" server will only be available at home. As you can imagine, the idea is basically the following: I get large amounts of mails, from all kind of mailing lists as well as personal mail. All that is filtered to a tree hierarchy of folders. There's a not fully secure mailserver, where mail arrives and which I can use when I'm on the way. It contains either just recent mails (the amount depending on the traffic of the list) or for selected senders/lists everything, and I control basically on a per folder basis how much should be retained (all, last 10 years, last week, etc.). There's another server, where *all* mail should eventually end up, for archival and security reasons. This implies obviously, that some of the mail is on both servers, some only on the "offline" server, and that this may vary from folder to folder. Further, on both servers, I may want to add filters, which basically split up a folder, e.g. of high traffic lists, so that mail of previous years or months is moved to subfolder structures, e.g.: linux-kernel +--2014 \--2013 and so on. So far, all that wouldn't be too difficult,... but as you can imagine, I'd like to have a bit more, which actually makes things quite tricky. How the two mailservers shall synchronise: I don't want to "simply" rsync - the whole system needs to be a bit smarter: 1) It's okay to assume, that synchronisation happens only at discrete times and not continuously (the "offline" server doesn't run always). 2) It would be ok, if the synchronisation requires a downtime of the "online" mailserver (i.e. the LDA). Since btrfs is used, I could also easily do snapshots. 3) One can also assume that, when synchronisation happens, the "offline" server contains at least all those folders, that the "online" server has as well (and possibly more). 4) Obviously, only maildir's cur/ directories should be synced (stuff in tmp&new may be still arriving). 5) As mentioned previously, not all mail may stay on the "online" server, depending on the folder, it will either stay permanently, or only for some period. 6) However, on the "offline" server, all mail stays, unless I manually delete it. 7) One must assume, that mails on *both* servers: - change their IMAP status (as in (S)een, (A)nswered, (F)lagged, etc.) - are moved to other mail folders - may be deleted via MUAs (not clear yet where this can happen) - "Fresh" mail, however, only appears on the "online" server. 8) Mails, once on the "offline" server, shouldn't be rewritten, in the sense that the mail is deleted and recreated (hopefully with the same content), which could happen either wenn the status of the mail changes or when it's moved to another folder (on the other server). The reason is simply, that I wouldn't fully trust the online server, so once the mail is local, it should be immutable (except for the status and folder location). The last, two points make things pretty difficult, or at least I wouldn't see a straightforward solution. (4) would be quite easy, e.g. when rsync would be used, then I'd just rsync all the cur/ directory. The rsync would happen not using --delete, so that mail which is no longer on the "online" server, doesn't get deleted from the "offline" server. (5) one could do, by "simply", on a per folder basis, remove mails older than X on the "online" server, after it has been copied to the "offline" server. An already existing tool for doing that would be nice, though. (7) and (8) is IMHO the most difficult: The only idea I have so far assumes that each mail file has an ID, which is unique for the *whole* mailbox (not just for each folder, as the mails may be moved between folders). The idea would be roughly, the following: * When I synchronise, I either shut down the LDA or make a snapshot of the "online" server's mailbox and work with that. * Then, I make a list (ID, status and pathname) of *all* mails on the online server and another one of *all* mails of the offline server. * Then, I probably scan for duplicate IDs in each list... just to be safe. * Then I process the mail lists as follows: a) If an ID is on *both* servers with the same status and pathname, than that mail had been previously synced already and neither moved nor changed its status since then. Nothing to do. b) If an ID is on *both* servers but with different pathnames or status, then the mail has either been moved or it's status has changed. Consequently, I would move/rename the mail to match the new location and/or IMAP-status. I would move/rename that with the older ctime to match the one with the newer (ctime gets set at move or rename and thus at status change). Even if an attacker would have fiddled with the "online" server's time or somehow else my system times were bogus, the worst that would happen was, that status changes are lost or mail ends up in the wrong folder. c) If an ID is on the "offline" server but not the "online" server, it could be either a mail that has already been garbage collected on the "online" server (so nothing would needed to be done),... or it could be mail hat was removed (via a MUA) on the "online" server and that should as well be removed on the "offline" server, either automatically, or manually after checking. How to find out which of that applies!? d) If an ID is on the "online" server but not the "offline" server, it could be either fresh mail that would needed to be synced,... or it could be mail that was removed on the "offline" server and should as well deleted on the "online" server, either automatically, or manually after checking. (a) and (b) are again rather simple, (c) and (d) not so much... Possible solutions that I could think of: - Either simply don't sync the removal of mails from the "online" server to the "offline" server and vice-versa. It will anyway happen rather rarely. - Remember a list of all IDs, that have been garbage collected on the "online" server. - Remebmer a list of all IDs, that have been removed via MUAs. => not sure if that's easily doable, probably not, is there any dierct way one could do this with dovecot. - Something to find out which mail has been gone on both, the each, the "offline" and the "online" server, since the last synchronisation, via tricks using the snapshot features of btrfs. - Somehow using the date of now and the last synchronisation and the mtimes (which are here basically like creation times, as the mail file contents never change). But I guess that would only work for (d) and not for (c),... and I'd rather not depend on times too much. * In any case, I could give the user a list of mails that would be deleted, for double checking. I actually think this would scale, as I don't expect many mails to be manually deleted through the MUA *once they had been synced*. After that, I think the two servers should be in sync - in the sense described in the beginning. Some further parts of the idea: As said, snapshots and the refcopy feature of btrfs could be quite helpful. So I could basically keep: - the "online" mailserver's mailbox - as of the last sync - as of now - the "offline" mailserver's mailbox - as of the last sync - as of now at the disk of the "offline" server without much additional cost. They'd all share reflinks and wouldn't use (much) additional space (except for fs meta-data) and I could use the snapshots to find out which files were deleted on either of the two servers since last time. Actually copying new mail from the "online" server to the offline server's disk (in the "as of now" area), could then happen via rsync'ing every cur/ from the "online" server to the "offline" server, with --delete and --ignore-existing (as I don't trust the "online" server and mail file contents should be immutable). So... questions... :D 1) Obviously, does anyone know a better solution, or has some improvements, other ideas? Or are there any problems with the above, which I haven't realised, or would you think it would work? 2) Does dovecot *ever* change the contents (i.e. the file contents) of a maildir mail file? 3) As ID I'd have thought that the maildir mail filename might work, e.g. 1234567890.M20046P2137.mailserver,S=4542,W=4642:2,Sb I mean especially the first part: 1234567890.M20046P2137.mailserver Is that unique across *all* folders of a mailbox? AFAIU, that name would be determined by whatever delivers the mail, right? So can I somehow configure that to make it unique? 4) Does dovecot ever change anything from the maildir mail filenames, except anything after the ":" above? I.e. would it ever change: 1234567890.M20046P2137.mailserver,S=4542,W=4642 ? 5) Would dovecot every copy, truncate+copy or somehow else rewrite files, instead of just moving them (i.e. thus possibly changing inodes, reflinks or that like)? 6) AFAIU, when using maildir, dovecots index files can get completely lost,... and one can fully "recover" all mails and their status. The only "bad" thing that might happen is that MUAs re-load all mail, right? 7) How graceful does dovceot handle the situation when mail is added or removed to/from cur/ by not using dovecot's IMAP,... especially with respect to index files. In the above solution I'd do a lot adding/moving/deleting files in maildirs, which would be done purely at the (file) system level, so the index would quite often get invalidated. How does it recognise that (if at all)? And is this generally stable, or should I rather remove any indexes after syncing and have them rebuilt by that? 8) All the above doesn't handle yet the thing of having yearly/monthly/etc. archive subfolders as described above, like: linux-kernel +--2014 \--2013 possibly on *both* "online" and "offline" server and possibly even in a different layout. I'm not yet sure whether this would be easily doable with the above solution,... my basic idea would be simply consider any such "archive" subfolders as the same than the "base" folder during syncing... and afterwards do re-order the mails on the "offline" and "online" server's folders as necessary. For example, if the "online" server has: linux-kernel +--01 +--02 +--03 ... \--12 in other words, one archive folder for the each of the last 12 months. While the "offline" server has: linux-kernel +--2014 \--2013 The script would then e.g. move the files to their new folders. => does anyone know, whether such thing exists already, i.e. a tool that sorts the mails into maildir subfolders, based on years, months, etc? 9) As said before, I'd like to be able to loose any indexes, but AFAICS, my solution wouldn't anyway work with sdbox. But if there's an sdbox based solution that makes everything much easier, do not hesitate to tell me :) 10) In the long-term I hope to be able to do something that makes server-side search (i.e. through the big fat mail archive) much faster (or is that already supported in dovecot?). I haven't really looked at all into that topic (just know about notmuch[0]). Anyway, if anyone sees problems in my above solution, when that would be used with something that gives me better server side search (i.e. some indexing solution),... I'd be happy to hear about that as well. Thanks a lot so far, Chris. [0] https://notmuchmail.org/

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Possible bug about the SPECIAL-USE / CREATE-SPECIAL-USE extensions
by Jeff Stedfast 20 Dec '15

20 Dec '15

Hi all, I've locally got Dovecot 2.2.21 (5345f22) installed on my MacBook (via homebrew) that I've been using to test my IMAP library against. What is interesting is that even though Dovecot does not advertise CREATE-SPECIAL-USE, it supports creation of special-use folders via the "CREATE FolderName (USE (\Whatever))" syntax. According to rfc6154, a server is supposed to advertise the CREATE-SPECIAL-USE extension if it supports this: An IMAP server that supports this OPTIONAL feature will advertise the "CREATE-SPECIAL-USE" capability string. Clients MUST NOT use the "USE" parameter unless the server advertises the capability. Note that this capability string is different from the "SPECIAL-USE" string defined above, and a server that supports both functions MUST advertise both capability strings. Has this been fixed in a newer version, perhaps? Or could it be a misconfiguration on my part? Attached is my dovecot configuration (gotten via dovecot -n). Thanks, Jeff

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Multiple IPs and hostname
by Thilo Engelbracht 18 Dec '15

18 Dec '15

Hi, I'm running postfix as SMTP-server and dovecot as IMAP-server. The server has multiple IPs, and postfix is configured that every domain is using a separate IPv4-address. Examle: foo1.com --> 11.22.33.44 foo2.com --> 22.33.44.55 foo3.com --> 33.44.55.66 bar.org --> 66.77.88.99 The hostname of the server is: mail.bar.org Now I have a request from one of my customers, who is using 3 different domains: - foo1.com - foo2.com - foo3.com If he receives a mail to "user(a)foo1.com", the header of the mail looks like this: Return-Path: <somebody(a)web.de> Delivered-To: <user(a)foo1.com> (II) Received: from mail.bar.org by mail.bar.org (Dovecot) with LMTP id V[...]wAAvP/pag for <user(a)foo1.com>; Sun, 29 Nov 2015 13:45:37 +0100 (I) Received: from mout.web.de (mout.web.de [212.227.17.11]) (using TLSv1.2 with cipher ECDHE-[...]-SHA384 (256/256 bits)) (No client certificate requested) by mail.foo1.com (Postfix) with ESMTPS id A[...]9 for <user(a)foo1.com>; Sun, 29 Nov 2015 13:45:36 +0100 (CET) As you can see in (I), postfix receives the mail and added a header with the correct hostname: mail.foo1.com But dovecot adds an additional header (see II). Here, the hostname of the system is visible. This is correct, because dovecot -n | grep -i hostname returns: hostname = mail.bar.org But my customer asks me if it's possible that only his domain is visible in the header: So, if somebody sends a mail to "user(a)foo1.com", only the hostname "mail.foo1.com" should be visible in the mail header. And if somebody sends a mail to "user(a)foo2.com", only the hostname "mail.foo2.com" should be visible in the mail header. Is there a way to do this? Thank you in advance. Kind regards Thilo

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Merry Christmas
by IT Security Inc. 18 Dec '15

18 Dec '15

Merry Christmas from IT Security Inc. 12/18/2015 Visit us online Merry Christmas to you and your family from Hugh Haggerty, myself and everyone else at IT Security,Inc. Albert Whale Hugh Haggerty IT Security Inc. Merry Christmas! IT Security, Inc. 519 Nichols Road Pittsburgh, PA 15237 | in2contact.co/front/tracking.jsp?clientID=858&campaignID=188&userID=731&linkID=B710C911120204FA&emailID=689&sendID=307&triggerID= | in2contact.co/front/tracking.jsp?clientID=858&campaignID=188&userID=731&linkID=EB9D07803CDFE734&emailID=689&sendID=307&triggerID=

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